Substance Sentence Examples

The future system I foresee will not be different in substance, but only in degree.

The substance of thought is language, and language is the one thing to teach the deaf child and every other child.

The mode of heating varies with the substance to be distilled.

Two chlorides of copper are known, one a highly coloured substance, the other quite white.

He believes that the capsule contains a substance which swells very rapidly when brought into contact with water, and that in the undischarged condition the capsule has its.

Similarly the substance we call wine is undeniably variable in composition.

The difficulty is solved by the provision of a complete system of minute intercellular spaces which form a continuous series of delicate canals between the cells, extending throughout the whole substance of the plant.

Cedria, or cedar resin, is a substance similar to mastic, that flows from incisions in the tree; and cedar manna is a sweet exudation from its branches.

When the substance operated upon is of uncertain composition, as, for example, coal, wood, coal-tar, &c., the term destructive distillation is employed.

His most original contribution to the substance of Roman literature was that he first shaped into poetry the experience of his own heart, as it had been shaped by Alcaeus and Sappho in the early days of Greek poetry.

If we examine such a substance as sugar we find that it can be broken up into fine grains, and these again into finer, the finest particles still appearing to be of the same nature as sugar.

The fundamental substance or stroma is colorless and homogeneous.

Glycogen, a substance related to starch and sugar, is found in the Fungi and Cyanophyceae as a food reserve.

Henry's demands were more defensible in substance than might be supposed from the manner in which he pressed them on the bishops.

But, in attempting to make this conception quite clear and thinkable, we are forced to represent the connexion of things as a universal substance, the essence of which we conceive as a system of laws which underlies everything and in its own self connects everything, but imperceptible, and known to us merely through the impressions it produces on us, which we call things.

The central body seems to consist merely of a spongy mass of slightly stainable substance, more or less impregnated with chromatin, which divides by constriction.

According to Lecointe, the young wall consists partly of cellulose and partly of a substance which is not cellulose, the latter existing in the form of slight depressions, which mark the position of the future pores.

As the sieve plate grows these non-cellulose regions swell and gradually become converted into the same kind of mucous substance as that contained in the tube; the two cells are thus placed in open communication.

But whereas the crystalline form of a chemical substance is stable and fixed, the organized form of a living organism is unstable and subject to change.

The change which took place during the 19th century in the substance and style of geography may be well seen by comparing the eight volumes of Malte-Brun's Geographic universelle (Paris, 1812-1829) with the twenty-one volumes of Reclus's Geographic universelle (Paris, 1876-1895).

Plant life, utilizing solar light to combine the inorganic elements of water, soil and air into living substance, is the basis of all animal life.

In the sequel he prepared a new evolutionary signal-book, which was adopted by the royal navy, and still remains in substance the foundation of the existing system of tactical evolutions at sea.

Leber experimented with several chemical compounds to find what reaction they had on these cells; by using fine glass tubes sealed at the outer end and containing a chemical substance, and by introducing the open end into the blood vessels he found that the leucocytes were attracted - positive chemiotaxis - by the various compounds of mercury, copper, turpentin, and other substances.

On the whole this century shows, in form, language and substance, the signs of literary decay.

The word is derived from the general resemblance of the texture of plant substance to that of a textile fabric, and dates from a period when the fundamental constitution of plant substance from individual cells was not yet discovered.

Cells of this type are often called trumpet-hyphae (though they have no connection with the hyphae of Fungi), and in some genera of Laminariaceae those at the periphery of the medulla simulate the sieve-tubes of the higher plants in a striking degree, even (like these latter) developing the peculiar substance callose on or in the perforated cross-walls or sieve-plates.

The peculiar substance called callose, chemically allied to cellulose, is frequently formed over the surface of the perforated end-walls.

They have emphasized the statements of Von Mohl, Cohn, and other writers alluded to, that the protoplasm is here also the dominant factor of the body, and that all the peculiarities of the cell-wall can only be interpreted in the light of the needs of the living substance.

Those organisms which possess the latter are a little higher in the scale of life than those which remain unclothed by it, but a comparison of the behaviour of the two quickly enables us to say that the membrane is of but secondary importance, and that for those which possess it, it is nothing more than a protective covering for the living substance.

If we pass a little higher up the scale ot life we meet with forms consisting of two or more cells, each of which contains a similar minute mass of living substance, A study of them shows that each is practically independent of the others; in fact, the connection between them is so slight that they can separate and each becofne free without the slightest disadvantage to another.

The second prominent differentiation which presents itself takes the form of a provision to supply the living substance with water.

The apparently structureless substance is saturated with it; and if once a cell is completely dried, even at a low temperature, in the enormous majority of cases its life iS gone and the restoration of water fails to enable it to recover.

There can be no doubt that there is no fundamental difference between the living substance of animals and plants, for many forms exist which cannot be referred with certainty to either kingdom.

The interest with which we regard the latter no longer turns upon the details of the structuie of its trunk, limbs and roots, to which the living substance of the more superficial parts was subordinated.

We see herein the reason for the great subdivision of the body, with its finely cut twigs and their ultimate expansions, the leaves, and we recognize that this subdivision is only an expression of the need to place the living substance in direct relationship with the environment.

Nature of the Food of Planls.The recognition of the fundamental identity of the living substance in animals and plants has directed attention to the manner in which plants are nourished, and especially to the exact nature of their food.

The idea was till recently currently accepted, that anything which plants absorbed from without, and which went to build up their organic substance, or to supply them with energy, or to exert some beneficial influence upon their metabolism, coiistituted their food.

If we examine the seat of active growth in a young root or twig, we find that the cells in which the organic substance, the protoplasm, of the plant is being formed and increased, are not supplied with carbon dioxide and mineral matter, but with such elaborated material as sugar and proteid substances, or others closely allied to them.

Identity of the Food of Animals and Plants.rt is evidently to the actual seats of consumption of food, and of consequent nutrition and increase of living substance, that we should turn when we wish to inquire what are the nutritive materials of plants.

The general vegetable protoplasm has not the capacity of being nourished by inorganic substances which are denied to the living substance of the animal world.

A consideration of these facts emphasizes still more fully the view with which we set out, that all living substance is fundamentally, the same, though differentiated both anatomically and physiologically in many directions and in different degrees.

It consists essentially of a number of minute corpuscles or plastids, the protoplasmic substance of which is impregnated with a green coloring matter.

The way in which such food when manufactured is incorporated into, and enabled to build up, the living substance is again hidden in obscurity.

The first of these, which may be regarded as growth proper, is the manufacture of additional quantities of living substance.

The outermost, newly formed layer is composed of a more homogeneous, denser substance than the inner one, and can be distinguished in all starch-grains that are in process of development.

Aleurone.Aleurone is a proteid substance which occurs in seeds especially those containing oil, in the form of minute granules or large grains.

It may be in the form of an albumen crystal sometimes associated with a more or less spherical bodygloboid-composed of a combination of an organic substance with a double phosphate of magnesium and calcium.

The Structure of the Nucleus.In the living condition the resting nucleus appears to consist of a homogeneous ground substance containing a large number of small chromatin granules and one or more large spherical granulesnucleolithe whole being surrounded by a limiting membrane which separates it from the cytoplasm.

When fixed and stained this granular mass is resolved into a more or less distinct granular network which consists of a substance called Linin, only slightly stained by the ordinary nuclear stains, and, embedded in it, a more deeply stainable substance called Chromatin.

Nuclein is a complex albuminoid substance containing phosphorus and iron in organic combination (Macallum).

It is generally surrounded by a granular or radiating cytoplasmic substance.

The chromatin substance increases in amount; the thread stains moie deeply, and in most cases presents a homogeneous appearance.

In order to effect this the individual chromosomes must become associated in some way, for there is no diminution in the actual amount of nuclear substance, and this leads to certain modifications in the division which are not seen in the vegetative nuclei.

It has been suggested that synapsis may be connected with the early longitudinal splitting of the thread or with the pairing of the chromosomes, but it is possible that it may be connected with the transference of nucleolar substance to the nuclear thread.

In the Cyanophyceae the contents of the cell are differentiated into a central colorless region, and a peripheral layer containing the chlorophyll and other coloring matters together with granules of a reserve substance called cyanophycin.

Just as every crystallizable chemical substance assumes a definite and constant crystalline form which cannot be accounted for otherwise than by regarding it as one of the properties of the substance, so every living organism assumes a characteristic form which is the outcome of the properties of its protoplasm.

When that is done, colchicine may be found to exhibit a definite chemical interaction with this hitherto undiscovered substance.

The substance known as "milk of sulphur" (lac sulphuris) is very finely divided sulphur produced by the following, or some analogous, chemical process.

If the viscous variety be rapidly cooled, or the more highly heated mass be poured into water, an elastic substance is obtained, termed plastic sulphur.

This substance, however, on standing becomes brittle.

Muscular substance forming the root of the foot.

Shaving soaps, which must obviously be free from alkali or any substance which irritates the skin, are characterized by readily forming a permanent lather.

Regarding all substances as being composed of one primitive matter - the prima materia, and as owing their specific differences to the presence of different qualities imposed upon it, the alchemist hoped, by taking away these qualities, to obtain the prima materia itself, and then to get from it the particular substance he desired by the addition of the appropriate qualities.

Turning to the study of radioactivity, he noticed its association with the minerals which yield helium, and in support of the hypothesis that that gas is a disintegration-product of radium he proved in 1903 that it is continuously formed by the latter substance in quantities sufficiently great to be directly recognizable in the spectroscope.

Following the great spring production of plant substance there is, therefore, a summer outburst of animal life.

Our present day definition of a cell is a minute portion of living organized substance or protoplasm.

The mucinoid substance is contained in the fine meshes.

Oddi in 1894 isolated from the amyloid liver a substance which Schmiedeberg had previously obtained from cartilage and named " chondroitinic-sulphuric acid " (Chondroitinschwefelsaure).

According to Maxwell (Theory of Heat) " When a continuous alteration of form is produced only by a stress exceeding a certain value, the substance is called a solid, however soft and plastic it may be.

If the substance operated upon be practically pure to start with, or the product of distillation be nearly of constant composition, the operation is termed "purification by distillation" or "rectification"; the latter term is particularly used in the spirit industry.

Bismuth disulphide is a grey metallic substance, which is decomposed by hydrochloric acid with the separation of metallic bismuth and the formation of bismuth trichloride.

The first, De Sancta Trinitate, is addressed to Symmachus (Domino Patri Symmacho), and the result of the short discussion, which is of an abstract nature, and deals partly with the ten categories, is that unity is predicated absolutely, or, in regard to the substance of the Deity, trinity is predicated relatively.

The mysteries of theology are its best part - not alien to reason but of its substance, the " logos."

The central apologetic thesis is the uniqueness of the "only-begotten"; it is here that " the supernatural " passes into the substance of Christian faith.

Dubois (1886), who considers that the luminosity is due to the influence of an enzyme in the cells of the organ upon a special substance in the blood.

It is supposed that these beetles secrete a sweet substance on which the ants feed, but they have been seen to devour the ants' eggs and grubs.

A prudent ruler in his position would have sought to preserve the outward forms while changing the inner substance, but Peter was not at all prudent in that sense.

It was always patent that what he was chiefly concerned with was the substance and the life of Christian truth, and that his whole energies were employed in this inquiry because his whole heart was engaged in the truths and facts which were at stake.

More original, perhaps, is the argument in the immediately preceding work, The Destiny of Man, viewed in the Light of his Origin (1884), which is, in substance, that physical evolution is a demonstrated fact; that intellectual force is a later, higher and more potent thing than bodily strength; and that, finally, in most men and some "lower animals" there is developed a new idea of the advantageous, a moral and non-selfish line of thought and procedure, which in itself so transcends the physical that it cannot be identified with it or be measured by its standards, and may or must be enduring, or at its best immortal.

That the substance of the Physiologus was borrowed from commentaries on Scripture 4 is confirmed by many of the sections opening with a text, followed up by some such formula as "but the Physiologus says."

Since the intrinsic energy of a substance varies with the conditions under which the substance exists, it is necessary, before proceeding to the practical application of any of the laws mentioned above, accurately to specify the conditions of the initial and final systems, or at least to secure that they shall not vary in the operations considered.

For ordinary combustions compressed oxygen is used, so that the combustible substance burns almost instantaneously, the action being induced by means of some electrical device which can be controlled from without the calorimeter.

Like Berthelot, he writes the chemical equation of the reaction, but in addition he considers the chemical formula of each substance to express not only its material composition, but also the (unknown) value of its intrinsic energy.

The substance will indeed remain, but in another form, another glory, another power " (De diligendo Deo, c. 10).

The unit of knowledge is not an isolated impression but a judgment; and in such a judgment is contained, even initially, the reference both to a permanent subject and to a permanent world of thought, and, implied in these, such judgments, for example, as those of existence, substance, cause and effect.

In the substance of their answer to Hume, the two philosophers have therefore much in common.

He was chosen Fourth of July orator in Hanover, the college town, in 1800, and in his speech appears the substance of the political principles for the develop - ment of which he is chiefly famous.

The body he regards as forming part of the substance of the soul, which through this union is more perfect and complete.

The non-nitrogenous substance (the fat) in the increase in live weight of an animal is, at any rate in great part, if not entirely, derived from the non-nitrogenous constituents of the food.

Hence it is that the amount of food consumed to produce a given amount of increase in live weight, as well as that required for the sustentation of a given live weight for a given time, should - provided the food be not abnormally deficient in nitrogenous substance - be characteristically dependent on its supplies of digestible and available non-nitrogenous constituents.

The whole of this surface appears to be active in the secretion of a mucous-like substance.

The lectures he delivered as professor form the substance of his two most important works, viz.

Many of the doctrinal portions may in substance well be still older, and date from the time of the Sassanids.

The platy minerals have also a perfect cleavage parallel to their flat surfaces, while the fibrous species often have two or more cleavages following their long axes; hence a schistose rock may split not only by separation of the mineral plates from one another but also by cleavage of the parallel minerals through their substance.

The cuticle is a dead substance, and is composed in large part of chitin.

Essential or inhering (formae inhaerentes) in the objects themselves are only substance, quantity, quality and relation in the stricter sense of that term.

It is clear from the treatise of Radbertus Paschasius already quoted that the word "substance" was used for reality as distinguished from outward appearance, and that the word "species" meant outward appearance as opposed to reality.

The definition of the Council of Trent was intended both to enforce the accepted Catholic position and to exclude the teaching of Luther, who, whilst not professing to be certain whether the "substance" of the Bread and Wine could or could not be said to remain, exclaimed against the intolerance of the Roman Catholic Church in defining the question.6 For a full and recent exposition of the Catholic teaching on Transubstantiation the reader may consult De ecclesiae sacra mentis, auctore Ludovico Billot, S.J.

He concluded that it was not common air, but the substance, "in much greater perfection," that rendered common air respirable and a supporter of combustion.

As men of substance increased among the ranks of the spinners, the Manchester cotton dealers found it impossible to retard a movement set on foot by the prospects of such appreciable advantages.

The substance of Caesar's account is as follows.

In 1853 and 1854 patents for the preparation of this substance from petroleum were obtained by Warren de la Rue, and the process was applied to the " Rangoon oil " brought to Great Britain from Yenangyaung in Upper Burma.

Although our information respecting the chemical composition of petroleum has been almost entirely gained since the middle of the 18th century, a considerable amount of empirical knowledge of the substance was possessed by chemists at an earlier date, and there was much speculation as to its origin.

In his Sylva sylvarum (1627), Francis Bacon states that " the original concretion of bitumen is a mixture of a fiery and watery substance," and observes that flame " attracts " the naphtha of Babylon " afar off."

In the latter we find the young Nemertines crawling about after a period of from six to eight weeks, and probably feeding upon a portion of this gelatinous substance, which is found to diminish in bulk.

Geoffroy in 1741 pointed out that the fat or oil recovered from a soap solution by neutralization with a mineral acid differs from the original fatty substance by dissolving readily in alcohol, which is not the case with ordinary fats and oils.

In preparing lead plaster by boiling olive oil with oxide of lead and a little water - a process palpably analogous to that of the soap-boilerhe obtained a sweet substance which, called by himself " Olsiiss " (" principium dulce oleorum "), is now known as " glycerin."

Almost any fatty substance can be employed in soap-making; but the choice is naturally restricted by the price of the fat and also the quality of the soap desired.

Yellow Soap consists of a mixture of any hard fatty soap with a variable proportion - up to 40% or more - of resin soap. That substance by itself has a tenacious gluey consistence, and its intermixture in excess renders the resulting compound soft and greasy.

It is here stirred till it becomes ropy, and the perfume, colour or any other substance desired in the soap is added.

It is readily understood why men imbued with the authority of tradition should prosecute the search for a substance which would confer unlimited wealth upon the fortunate discoverer.

At the same time he clarified the conception of elements and compounds, rejecting the older notions, the four elements of the " vulgar Peripateticks " and the three principles of the " vulgar Stagyrists," and defining an element as a substance incapable of decomposition, and a compound as composed of two or more elements.

On the one hand, it had been held that when a substance was burned or calcined, it combined with an " air "; on the other hand, the operation was supposed to be attended by the destruc tion or loss of the igneous principle.

He regarded the chemical properties of a substance as due to (1) the chemical atoms composing it, and (2) the structure, and he asserted that while different compounds might have the same components (isomerism), yet only one compound could have a particular structure.

A molecule may be defined as the smallest part of a substance which can exist alone; an atom as the smallest part of a substance which can exist in combination.

An alkali or base is a substance which neutralizes an acid with the production of salts but with no evolution of hydrogen.

In all cases of chemical change energy in the form of heat is either developed or absorbed, and the amount of heat developed or absorbed in a given reaction is as definite as are the weights of the substance engaged in the reaction.

Thus, chlorine enters into reaction with hydrogen, and removes hydrogen from hydrogenized bodies, far more readily than bromine; and hydrochloric acid is a far more stable substance than hydrobromic acid, hydriodic acid being greatly inferior even to hydrobromic acid in stability.

The second discovery, associated with the Curies, is that of the peculiar properties exhibited by the impure substance, and due to a constituent named radium.

The chemical analogy of this substance to chlorine was quickly perceived, especially after its investigation by Davy and Gay Lussac. Cyanogen, a compound which in combination behaved very similarly to chlorine and iodine, was isolated in 1815 by Gay Lussac. This discovery of the first of the then-styled " compound radicals " exerted great influence on the prevailing views of chemical composition.

In 1841 Mosander, having in 1839 discovered a new element lanthanum in the mineral cerite, isolated this element and also a hitherto unrecognized substance, didymia, from crude yttria, and two years later he announced the determination of two fresh constituents of the same earth, naming them erbia and terbia.

But the belief died hard; the synthesis of urea remained isolated for many years; and many explanations were attempted by the vitalists (as, for instance, that urea was halfway between the inorganic and organic kingdoms, or that the carbon, from which it was obtained, retained the essentials of this hypothetical vital force), but only to succumb at a later date to the indubitable fact that the same laws of chemical combination prevail in both the animate and inanimate kingdoms, and that the artificial or laboratory synthesis of any substance, either inorganic or organic, is but a question of time, once its constitution is determined.'.

We derived this substance from ethane by introducing a meth y l group; hence it may be termed " methylethane."

These three acids yield on heating phenol, identical with the substance started with, and since in the three oxybenzoic acids the hydroxyl groups must occupy positions other than I, it follows that four hydrogen atoms are equal in value.

This substance readily yields ortho-oxybenzoic acid or salicylic acid, which on nitration yields two mononitro-oxybenzoic acids.

Carius showed that potassium chlorate and sulphuric acid oxidized benzene to trichlorphenomalic acid, a substance afterwards investigated by Kekule and 0.

Potassium chlorate and hydrochloric acid oxidize phenol, salicylic acid (o-oxybenzoic acid), and gallic acid ([2.3.4] trioxybenzoic acid) to tri chlorpyroracemic acid (isotrichlorglyceric acid), CC13 C(OH)2 C02H, a substance also obtained from trichloracetonitrile, CC1 3 CO CN, by hydrolysis.

This substance is transformed into hexachlor-R-pentene oxycarboxylic acid (3) when digested with water; and chromic acid oxidizes this substance to hexachlor-R-pentene (4).

Bromine water oxidizes this substance to oxalic acid and tetrabromdichloracetone (5).

The former pointed out that the supposed isomerism was not due to an arrangement of atoms, but to the disposition of a valency, and therefore it was doubtful whether such a subtle condition could exert any influence on the properties of the substance.

The formation of this substance readily follows from Kekule's formula, while considerable difficulties are met with when one attempts an explanation based on Ladenburg's representation.

Thus benzene, (CH) gives thiophene, (CH) S, from which it is difficultly distinguished; pyridine, (CH) N, gives thiazole, (CH) N S, which is a very similar substance; naphthalene gives thionaphthen, C 11 S, with which it shows great analogies, especially in the derivatives.

This is comparable with the reduction of the benzene nucleus into hexamethylene, a substance of an aliphatic character.

In his earlier experiments he burned the substance in a known volume of oxygen, and by measuring the residual gas determined the carbon and hydrogen.

It must be mentioned here that the reactions of any particular substance are given under its own heading, and in this article we shall only collate the various operations and outline the general procedure.

Note whether any moisture condenses on the cooler parts of the tube, a gas is evolved, a sublimate formed, or the substance changes colour.

Heat the substance on a piece of charcoal in the reducing flame of the blowpipe.

Hold a small portion of the substance moistened with hydrochloric acid on a clean platinum wire in the fusion zone' of the Bunsen burner, and note any colour imparted to the flame.

It is first necessary to get the substance into solution.

If, however, phosphoric acid is present in the original substance,we may here obtain a precipitate of the phosphates of the remaining metals, together with aluminium, chromium and ferric hydrates.

Sometimes it is necessary to allow the solution to stand for a considerable time either in the warm or cold or in the light or dark; to work with cold solutions and then boil; or to use boiling solutions of both the substance and reagent.

If the substance to be weighed changes in composition on strong heating, it is necessary to employ a tared filter, i.e.

We know the amount present in the precipitate, and since the same amount is present in the quantity of substance experimented with, we have only to work out a sum in proportion.

In general analytical work the standard solution contains the equivalent weight of the substance in grammes dissolved in a litre of water.

Standard solutions are prepared by weighing out the exact amount of the pure substance and dissolving it in water, or by forming a solution of approximate normality, determining its exact strength by gravimetric or other means, and then correcting it for any divergence.

The general procedure is to make a series of standard solutions containing definite quantities of the substance which it is desired to estimate; such a series will exhibit tints which deepen as the quantity of the substance is increased.

A known weight of the test substance is dissolved and a portion of the solution is placed in a tube similar to those containing the standard solutions.

Carbon is detected by the formation of carbon dioxide, which turns lime-water milky, and hydrogen by the formation of water, which condenses on the tube, when the substance is heated with copper oxide.

Nitrogen may be detected by the evolution of ammonia when the substance is heated with soda-lime.

The substance is heated with metallic sodium or potassium (in excess if sulphur be present) to redness, the residue treated with water, filtered, and ferrous sulphate, ferric chloride and hydrochloric acid added.

Beilstein determines their presence by heating the substance with pure copper oxide on a platinum wire in the Bunsen flame; a green coloration is observed if halogens be present.

Sulphur is detected by heating the substance with sodium, dissolving the product in water, and adding sodium nitroprusside; a bluish-violet coloration indicates sulphur.

Horbaczewski's method, which consists in boiling the substance with strong potash, saturating the cold solution` with chlorine, adding hydrochloric acid, and boiling till no more chlorine is liberated, and then testing for sulphuric acid with barium chloride.

Phosphorus is obtained as a soluble phosphate (which can be examined in the usual way) by lixiviating the product obtained when the substance is ignited with potassium nitrate and carbonate.

Carbon and hydrogen are generally estimated by the combustion process, which consists in oxidizing the substance and absorbing the products of combustion in suitable apparatus.

The space a must allow for the inclusion of a copper spiral if the substance contains nitrogen, and a silver spiral if halogens be present, for otherwise nitrogen oxides and the halogens may be condensed in the absorption apparatus; b contains copper oxide; c is a space for the insertion of a porcelain or platinum boat containing a weighed quantity of the substance; d is a copper spiral.

After having previously roasted the tube and copper oxide, and reduced the copper spiral a, the weighed calcium chloride tube and potash bulbs are put in position, the boat containing the substance is inserted (in the case of a difficultly combustible substance it is desirable to mix it with cupric oxide or lead chromate), the copper spiral (d) replaced, and the air and oxygen supply connected up. The apparatus is then tested for leaks.

The success of the operation depends upon the slow burning of the substance.

In 1855 C. Brunner described a method for oxidizing the carbon to carbon dioxide, which could be estimated by the usual methods, by heating the substance with potassium bichromate and sulphuric acid.

Methods depending upon oxidation in the presence of a contact substance have come into favour during recent years.

Dennstedt, which was first proposed in 1902, the substance is vaporized in a tube containing at one end platinum foil, platinized quartz, or platinized asbestos.

Nitrogen is estimated by (I) Dumas' method, which consists in heating the substance with copper oxide and measuring the volume Nitrogen.

This artifice is specially valuable when the substance decomposes or volatilizes in a warm current of carbon dioxide.

In the first method the substance, mixed with quicklime free from chlorine, is heated in a tube closed at one end in a combustion furnace.

Eliminating a and b between these relations, we derive P k V k /Tk= 8R, a relation which should hold between the critical constants of any substance.

Kopp, begun in 1842, on the molecular volumes, the volume occupied by one gramme molecular weight of a substance, of liquids measured at their boiling-point under atmospheric pressure, brought to light a series of additive relations which, in the case of carbon compounds, render it possible to predict, in some measure, the cornposition of the substance.

In practice it is generally more convenient to determine the density, the molecular volume being then obtained by dividing the molecular weight of the substance by the density.

Van der Waal's equation (p-I- a/v 2) (v - b) = RT contains two constants a and b determined by each particular substance.

It is to be noted that although the correlation of melting-point with constitution has not been developed to such an extent as the chemical significance of other physical properties, the melting-point is the most valuable test of the purity of a substance, a circumstance due in considerable measure to the fact that impurities always tend to lower the melting-point.

It is there shown that every substance, transparent to light, has a definite refractive index, which is the ratio of the velocity of light in vacuo to its velocity in the medium to which the refractive index refers.

He introduced the idea of comparing the refractivity of equimolecular quantities of different substances by multiplying the function (n-1)/d by the molecular weight (M) of the substance, and investigated the relations of chemical grouping to refractivity.

Although establishing certain general relations between atomic and molecular refractions, the results were somewhat vitiated by the inadequacy of the empirical function which he employed, since it was by no means a constant which depended only on the actual composition of the substance and was independent of its physical condition.

Quinone, which is light yellow in colour, is the simplest coloured substance on this theory.

This theory explains the fluorescence of anthranilic acid (o-aminobenzoic acid), by regarding the aniline residue as the luminophore, and the carboxyl group as the fluorogen, since, apparently, the introduction of the latter into the non-fluorescent aniline molecule involves the production of a fluorescent substance.

Obviously equimolecular surfaces are given by (Mv) 3, where M is the molecular weight of the substance, for equimolecular volumes are Mv, and corresponding surfaces the two-thirds power of this.

Now the value of K, -y being measured in dynes and M being the molecular weight of the substance as a gas, is in general 2.121; this value is never exceeded, but in many cases it is less.

Isomorphism may be defined as the existence of two or more different substances in the same crystal form and structure, polymorphism as the existence of the same substance in two or more crystal modifications, and morphotropy (after P. von Groth) as the change in crystal form due to alterations in the molecule of closely (chemically) related substances.

When precipitated from solutions it forms red tetragonal crystals, which, on careful heating, give a yellow rhombic form, also obtained by crystallization from the fused substance, or by sublimation.

The physical conditions under which polymorphous modifications are prepared control the form which the substance assumes.

From supersaturated solutions the form unstable at the temperature of the experiment is, as a rule, separated, especially on the introduction of a crystal of the unstable form; and, in some cases, similar inoculation of the fused substance is attended by the same result.

If a substance deposits itself on the faces of a crystal of another substance of similar crystal form, the substances are probably isomorphous.

In 1798 he presented to the Royal Society his "Enquiry concerning the Source of Heat which is excited by Friction," in which he combated the current view that heat was a material substance, and regarded it as a mode of motion.

Wordsworth's theories of poetry - the objects best suited for poetic treatment, the characteristics of such treatment and the choice of diction suitable for the purpose - may be said to have grown out of the soil and substance of the lakes and mountains, and out of the homely lives of the people, of Cumberland and Westmoreland.

This substance easily splits out alcohol, and the ring compound then formed yields pyrrolidine on reduction by sodium in amyl alcohol solution.

Another view is that the colour is due to some comparatively simple substance suspended in a colourless medium.

It results from this that the horn has the appearance of a mass of agglutinated hairs, which, in the newly growing part at the base, readily fray out on destruction of the softer intermediate substance; but the fibres differ from true hairs in growing from a free papilla of the derm, and not within a follicular involution of the same.

This first Sephirah, this spiritual substance which existed in the En Soph from all eternity, contained nine other intelligences or Sephiroth.

Its ten Sephiroth, being still farther removed from the Primordial Source, are of a less refined substance.

Its ten Sephiroth are made up of the grosser elements of the former three worlds; they consist of material substance limited by space and perceptible to the senses in a multiplicity of forms. This world is subject to constant changes and corruption, and is the dwelling of the evil spirits.

The project of the Code Napoleon, however - the code itself not being available in Louisiana, though promulgated in France in 1804 - was used by the compilers in the arrangement and substance of their work; and the French traditions of the colony, thus illustrated, were naturally introduced more and more into the organic commentaries and developments that grew up around the Code Napoleon.

On reduction it gives a strongly reducing substance, probably hydrazine.

If it was due to Livius that the forms of Latin literature were, from the first, moulded on those of Greek literature, it was due to Naevius that much of its spirit and substance was of native growth.

Cleve, Lecoq de Boisbaudran and others into erbia, holmia, thulia and dysprosia, but it is still doubtful whether any one of these four splitting products is a single substance.

These facts of distribution are due to certain conditions that govern the production of organic substance in the oceans.

Now dead animal substance and the excreta of animals decompose in the long run into carbonic acid, water and mineral salts, and so there is a continual destruction of animal substance both on the land and in the sea.

Clearly, however, the vast quantity of living substance in the ocean is built up from materials that are present in the sea-water as an exceedingly dilute solution, and the solution is dilute just because organisms are incessantly utilizing it.

It follows, too, that when there is a number of substances, all essential for the elaboration of living material, and when one of these is present in minimal proportion, that one substance rules the production, just as the effective strength of a chain depends on the weakest link.

In the end much inorganic nitrogen salts must be added to the sea both in the above way and as the result of the putrefaction of the dead substance of terrestrial animals and plants.

Fibrin, produced from fibrinogen by a ferment, is a jelly-like substance, coagulable by heat, alcohol, &c. The muscle-albumins include " myosin " or paramyosinogen, a globulin, which by coagulation induces rigor mortis, and the closely related " myosinogen " or myogen; myoglobulin and myoalbumin are also found in muscles.

By the rennet ferment caseinogen is converted into casein, a substance resembling caseinogen in being soluble in water, but differing in having an insoluble calcium salt.

An important nucleo-proteid is haemoglobulin or haemoglobin, the colouring matter of the red blood corpuscles of vertebrates; a related substance, haemocyanin, in which the iron of haemoglobin is replaced by copper, occurs in the blood of cephalopods and crayfish.

Haemoglobin is composed of a basic albumin and an acid substance haematin; it combines readily with oxygen, carbon dioxide and carbon monoxide to form loose compounds.

This last substance may be reduced to mesoporphyrin, C34H3804N4, which by further reduction gives haemopyrrol, C 8 11 13 N, possibly methyl-propyl-pyrrol or butyl-pyrrol.

Gelatin occurs also in the cornea and the sclerotic coat of the eye; and in fish scales, the latter containing 80% of collagen, and 20% of ichthylepidin, a substance differing from gelatin in giving a wellmarked Millon's reaction.

Related to this substance are " neuro-keratin," found in the medullary sheath of nerves, and " gorgonin," the matrix of the axial skeleton of the coral Gorgonia Cavolinii.

The substance known as moldavite, often regarded as an obsidian, and the so-called obsidian bombs, or obsidianites, are described under MOLDAVITE.

When the passage of an electric current through a substance is accompanied by definite chemical changes which are independent of the heating effects of the current, the process is known as electrolysis, and the substance is called an electrolyte.

The electrochemical equivalent of any other substance, whether element or compound, may be found by multiplying its chemical equivalent by I 036X Io-5.

When the ions are set free at the electrodes, they may unite with the substance of the electrode or with some constituent of the solution to form secondary products.

Thus, if the molecule of a substance in solution is represented by AB, Grotthus considered a chain of AB molecules to exist from one electrode to the other.

The chemical activity of a substance is a quantity which may be measured by different methods.

The number of undissociated molecules is then I - a, so that if V be the volume of the solution containing I gramme-molecule of the dissolved substance, we get q= and p= (I - a)/V, hence x(I - a) V =yd/V2, and constant = k.

We can calculate the heat of formation from its ions for any substance dissolved in a given liquid, from a knowledge of the temperature coefficient of ionization, by means of an application of the well-known thermodynamical process, which also gives the latent heat of evaporation of a liquid when the temperature coefficient of its vapour pressure is known.

In ordinary cells the difference is secured by using two dissimilar metals, but an electromotive force exists if two plates of the same metal are placed in solutions of different substances, or of the same substance at different concentrations.

Silver chloride is a very insoluble substance, and here the amount in solution is still further reduced by the presence of excess of chlorine ions of the potassium salt.

According to the molecular theory, diffusion is due to the motion of the molecules of the dissolved substance through the liquid.

The difference of potential between two solutions of a substance at different concentrations can be calculated from the equations used to give the diffusion constants.

On the analogy between this case and that of the interface between two solutions, Nernst has arrived at similar logarithmic expressions for the difference of potential, which becomes proportional to log (P 1 /P 2) where P2 is taken to mean the osmotic pressure of the cations in the solution, and P i the osmotic pressure of the cations in the substance of the metal itself.

It has been compared with that of milk and of blood, which depend essentially on the coagulation or separation in curds of a proteid or albuminous substance, such as takes place when white of egg is warmed.

Rubber is chiefly composed of the soft, solid, elastic substance known as caoutchouc. It is usually assumed that this substance is present as such in the latex.

The globules in the latex, however, consist more probably of a distinct liquid substance which readily changes into the solid caoutchouc. The coagulation of the latex often originates with the " curding " of the proteids present, and this alteration in the proteid leads to the solidification of the globules into caoutchouc. The latter, however, is probably a distinct effect.

It is already certain that some commercial rubbers contain a variable proportion of a substance of the nature of caoutchouc, but having different properties.

True caoutchouc, the principal constituent of all rubbers, is probably essentially one and the same substance, from whatever botanical source it may have been derived.

When this volatile liquid hydrocarbon (isoprene) is allowed ro stand for some time in a closed bottle, it gradually passes into a substance having the principal properties of natural caoutchouc. The same change of isoprene into caoutchouc may also be effected by the action of certain chemical agents.

Rubber slowly absorbs oxygen when exposed to air and light, the absorption of oxygen being accompanied by a gradual change in the characteristic properties of rubber, and ultimately to the production of a hard, inelastic, brittle substance containing oxygen.

Most of the rubber now manufactured is not combined with sulphur when in the form of sheets, but is mechanically incorporated with about one-tenth of its weight of that substance by means of the mixing rollers - any required pigment or other matter, such as whiting or barium sulphate, being added.

These often have the form of prisms of calcite surrounded by a cuti cular meshwork; the whole is nourished and kept alive by processes, which in Crania are branched; these perforate the shell and permit the access of the coelomic fluid throughout its substance.

In regard to the ancients' knowledge of lead compounds, we may state that the substance described by Dioscorides as, uoXv,3Saiva was undoubtedly litharge, that Pliny uses the word minium in its present sense of red lead, ana that white lead was well known to Geber in the 8th century.

The Kassner process for the manufacture of oxygen depends upon the formation of calcium plumbate, Ca2Pb04, by heating a mixture of lime and litharge in a current of air, decomposing this substance into calcium carbonate and lead dioxide by heating in a current of carbon dioxide, and then decomposing these compounds with the evolution of carbon dioxide and oxygen by raising the temperature.

Thus caught between two fires the casuists developed a highly ingenious method, not unlike that of the Roman Stoics, for eviscerating the substance of a rule while leaving its shadow carefully intact.

When the magnetic induction flows through a piece of iron or other magnetizable substance placed near the magnet, a south pole is developed where the flux enters and a north pole where it leaves the substance.

According to this theory the molecules of any magnetizable substance are little permanent magnets the axes of which are, under ordinary conditions, disposed in all possible directions indifferently.

On the other hand, the magnetic properties of a substance are affected by such causes as mechanical stress and changes of temperature.

The ratio I/H is called the susceptibility of the magnetized substance, and is denoted by «.

From the equation K=(µ - I)/47r, it follows that the magnetic susceptibility of a vacuum (where µ = I) is o, that of a diamagnetic substance (where, u I) is positive.

No substance has yet been discovered having a negative susceptibility sufficiently great to render the permeability (= I +471K) negative.

The body (or each element of it) will tend to set itself with its axis of greatest susceptibility parallel to the lines of force, while, if the field is not uniform, each volume-element will also tend to move towards places of greater or smaller force (according as the substance is paramagnetic or diamagnetic), the tendency being a maximum when the axis of greatest susceptibility is parallel to the field, and a minimum when it is perpendicular to it.

The intensity of a field may be measured by the rotation of the plane of polarization of light passing in the direction of the magnetic force through a transparent substance.

If the field is uniform, H=O/wd, where 0 is the rotation, d the thickness of the substance arranged as a plate at right angles to the direction of the field, and w Verdet's constant for the substance.

Ordinary magnetizable iron is in many respects an essentially different substance from the non-magnetizable metal into which it is transformed when its temperature is raised above a certain point.

If, however, this non-magnetic substance is cooled to a temperature a few degrees below freezing-point, it becomes as strongly magnetic as average cast-iron (µ = 62 for H = 40), and retains its magnetic properties indefinitely at ordinary temperatures.

A sample of Hadfield's manufacture, containing 1 2.36% of manganese, differed hardly at all from a non-magnetic substance, its permeability being only 1.27.

The strength of the induced current is - HScosO/L, where 0 is the inclination of the axis of the circuit to the direction of the field, and L the coefficient of self-induction; the resolved part of the magnetic moment in the direction of the field is equal to - HS 2 cos 2 6/L, and if there are n molecules in a unit of volume, their axes being distributed indifferently in all directions, the magnetization of the substance will be-3nHS 2 /L, and its susceptibility - 3S 2 /L (Maxwell, Electricity and Magnetism, § 838).

If the structure of the molecule is so perfectly symmetrical that, in the absence of any external field, the resultant magnetic moment of the circulating electrons is zero, then the application of a field, by accelerating the right-handed (negative) revolutions, and retarding those which are left-handed, will induce in the substance a resultant magnetization opposite in direction to the field itself; a body composed of such symmetrical molecules is therefore diamagnetic. If however the structure of the molecule is such that the electrons revolving around its atoms do not exactly cancel one another's effects, the molecule constitutes a little magnet, which under the influence of an external field will tend to set itself with its axis parallel to the field.

Ordinarily a substance composed of asymmetrical molecules is paramagnetic, but if the elementary magnets are so conditioned by their strength and concentration that mutual action between them is possible, then the substance is ferromagnetic. In all cases however it is the diamagnetic condition that is initially set up - even iron is diamagnetic - though the diamagnetism may be completely masked by the superposed paramagnetic or ferromagnetic condition.

A magnetizable substance was supposed to consist of an indefinite number of spherical particles, each containing equivalent quantities of the two fluids, which could move freely within a particle, but could never pass from one particle to another.

Gray; but Dumeril and Bibron in their great work,' and Dr Gunther in his Catalogue, in substance, adopted Brongniart's arrangement, the Batrachia being simply one of the four orders of the class Reptilia.

One of the first of these attacks was made by Berengarius of Tours (999-1088) upon the doctrine of transubstantiation; he denied the possibility of a change of substance in the bread and wine without some corresponding change in the accidents.

From the scanty and ill-natured notices of his opponents (Anselm and Abelard), we gather that he refused to recognize the reality of anything but the individual; he treated " the universal substance," says Anselm, as no more than " flatum vocis," a verbal breathing or sound; and in a similar strain he denied any reality to the parts of which a whole, such as a house, is commonly said to be composed.

It is a Realism of the most uncompromising type, which by its reduction of individuals to accidents of one identical substance seems to tremble on the very verge of Spinozism.

He taught, says Abelard, that the same thing or substance was present in its entirety and essence in each individual, and that individuals differed no whit in their essence but only in the variety of their accidents.

Thus " Socratitus " is merely an accident of the substance "humanitas," or, as it is put by the author of the treatise De generibus et speciebus, 1 " Man is a species, a thing essentially one (res una essentialiter), which receives certain forms which make it Socrates.

What exists as a substance and the basis of qualities or forms (quod est) may be said substare; the forms on the other hand by which such an individual substance exists qualitatively (quo est) subsistent, though it cannot be said that they substant.

The intellect collects the universal, which exists but not as a substance (est sed non substat), from the particular things which not merely are (sunt) but also, as subjects of accidents, have substantial existence (substant), by considering only their substantial similarity or conformity.

Abelard also perceived that Realism, by separating the universal substance from the forms which individualize it, makes the universal indifferent to these forms, and leads directly to the doctrine of the identity of all beings in one universal substance or matter - a pantheism which might take either an Averroistic or a Spinozistic form.

For that system still seems to recognize a generic substance as the core of the individual, whereas, according to Cousin's rendering of Abelard's doctrine, " only individuals exist, and in the individual nothing but the individual."

Holding fast then on the one hand to the individual as the only true substance, and on the other to the traditional definition of the genus as that which is predicated of a number of individuals (quod praedicatur de pluribus), Abelard declared that this definition of itself condemns the Realistic theory; only a name, not a thing, can be so predicated - not the name, however, as a flatus vocis or a collection of letters, but the name as used in discourse, the name as a sign, as having a meaning - in a word, not vox but sermo.

What Abelard combats is the substantiation of these resembling qualities, which leads to their being regarded as identical in all the separate individuals, and thus paves the way for the gradual undermining of the individual, the only true and indivisible substance.

Richard Chevenix (1774-1830), a chemist, having bought some of the substance, decided after experiment that it was not a simple body as claimed, but an alloy of mercury with platinum, and in 1803 presented a paper to the Royal Society setting forth this view.

But having failed, he allowed the paper, and also a second by Chevenix of the same tenor in 1805, to be read without avowing that it was he himself who had originally detected the metal, although he had an excellent opportunity of stating the fact in 1804 when he discussed the substance in the paper which announced the discovery of rhodium.

In taking this course Joseph made the capital mistake of neglecting the Machiavellian maxim that in changing the substance of cherished institutions the prince should be careful to preserve the semblance.

Weismann has also ingeniously argued from the structure of the egg-cell and sperm-cell, and from the way in which, and the period at which, they are derived in the course of the growth of the embryo from the egg - from the fertilized egg-cell - that it is impossible (it would be better to say highly improbable) that an alteration in parental structure could produce any exactly representative change in the substance of the germ or sperm-cells.

If, as in common flint-glass spectroscopes, there is only one dispersing substance, f Sy ds = Sµ.s, where s is simply the thickness traversed by the ray.

He declared that he had preserved the thing in its substance, if he had not actually used the word; and this view of the matter was always officially maintained in the colonial office (which, significantly enough, dealt with Transvaal affairs) whatever the political party in power.

Thus an individual living body is not only constantly changing its substance, but its size and form are undergoing continual modifications, the end of which is the death and decay of that individual; the continuation of the kind being secured by the detachment of portions which tend to run through the same cycle of forms as the parent.

And it remains to be seen, how far the death of any form of living matter, at a given temperature, depends on the destruction of its fundamental substance at that heat, and how far death is brought about by the coagulation of merely accessory compounds.

The broad distinctions which, as a matter of fact, exist between every known form of living substance and every other component of the material world, justify the separation of the biological sciences from all others.

Stannous bromide, SnBr 2, is a light yellow substance formed from tin and hydrobromic acid.

Beginning with the earliest versions of the Bible, which seem to date from the 2nd century A.D., the series comprises a great mass of translations from Greek originals - theological, philosophical, legendary, historical and scientific. In a fair number of cases the Syriac version has preserved to us the substance of a lost original text.

This colouring power is due to the presence of polychlorite, a substance whose chemical formula appears to be C4 8 1-160018, and which may be obtained by treating saffron with ether, and afterwards exhausting with water.

He drew up schemes for departmental normal schools, for primary schools (reviving in substance the Projet) and central schools.

The idea is that any traces of acid not washed away by the washing process or produced later by a slow decomposition of the substance will be thereby neutralized and rendered harmless.

It is questionable if the substance in question is mucoid.

If, for instance, we find that instead of the natural number of Malpighian bodies in the kidney there are only half that number, then we are entitled to say that this defect represents disease of structure; and if we find that the organ is excreting a new substance, such as albumen, we can affirm logically that its function is abnormal.

The fatty matter, however, it must be borne in mind, is the expression of dissimilation of the actual substance of the proteids of the tissues, not of the splitting up of proteids or other carbonaceous nourishment supplied to them.

Some organs are subject to enlargement from deposition within them of a foreign substance (amyloid, fat, &c.).

Assuming, with Sedgwick and others, this amassed and bound condition of the tissues to be true, it would be necessary to reject the cell-doctrine in pathology altogether, and to regard the living basis of the organism as a continuous substance whose parts are incapable of living independently of the whole.

The cell body, or cytoplasm, is apparently composed of a fine reticulum or network, containing within the meshes a soft viscid, transparent substance, the cell-sap, or hyaloplasm, which is probably a nutrient material to the living cell.

It was also found that a weak solution may have a marked positive attraction whilst a strong solution of the same substance will have the opposite effect.

It is from these cells that the fine fibrillar substance is formed, and from this stage onwards - eight to fifteen days - there is a steady increase in the new fibrils, giving more density to the new tissue.

They supposed that it was accompanied by a peculiar hyaline thickening of the arterial wall, usually of the tunica intima, and hence they termed the supposed diseased state " arterio-capillary fibrosis," and gave the fibrous substance the name " hyaline-fibroid."

The fact that it is possible to propagate these cells of one animal for years in other animals of the same species, without any loss of their vegetative vitality, suggests that this continued growth is kept up by a growth-stimulating substance present in the proper species of animal; this substance, however, has not the power of transforming the normal tissue into a cancerous one.

By mucoid is understood a soft gelatinous substance containing mucin, or pseudomucin, which is normally secreted by the epithelial cells of both the mucous membranes and glands.

The desquamated cells containing this jelly-like substance become disorganized and blend with the secretion.

This term is usually applied to a semi-solid substance of homogeneous and gelatinous consistence, which results partly from excretion and partly from degeneration of cellular structures, more particularly of the epithelial type.

These cells become swollen by this translucent substance and are thrown off into the space where they become fused together, forming colloid masses.

This substance differs from the mucins by being precipitated by tannic acid but not by acetic acid, and being endowed with a higher proportion of sulphur.

This pigment is usually intracellular, but may be found lying free in the intercellular substance, and is generally in the form of fine granules of a yellowish-brown or brown-black colour.

This pigment is of a light yellow colour, and contains a fatty substance that reacts to the fat-staining reagents.

The substance is very resistant to the action of chemical reagents, to digestion, and possibly belongs to the glyco-proteids.

The wax-like or amyloid substance has a certain resemblance to the colloid, mucoid and hyaline.

Oddi does not regard it as the essential constituent of amyloid, chiefly because the colour reactions are forthcoming in the residuum after the substance has been removed, while the substance itself does not give these reactions.

This amyloid substance is slowly and imperfectly digested by pepsin - digestion being more complete with trypsin and by autolytic enzymes.

Thus Krawkow and Nowak, employing the frequent subcutaneous injection of the usual organisms of suppuration, have induced in the fowl the deposition within the tissues of a homogeneous substance giving the colour reactions of true amyloid.

If a healthy spinal cord be hung up in spirit for a matter of six months or more, a glassy substance develops within it quite like true amyloid.

The influence of the chemical substance is either that of attraction or repulsion, the one being known as positive, the other as negative chemiotaxis.

No other substance, at least, with which he experimented had a like effect, and it is possible that in the archegonium which contains the ovum malic acid is present.

Melanine particles formed in the spleen in malaria, which pass along with the blood through the liver, are appropriated by the endothelial cells of the hepatic capillaries, and are found embedded within their substance.

They surround individual bacteria, absorb them into their substance, and ultimately destroy them by digestion.

The liquid when soaked into a porous combustible substance like blotting-paper burns rapidly and quietly, and when struck with a hammer on a hard surface violently detonates; when a little of the liquid is spread on an anvil and struck, the portion immediately under the hammer only will, as a rule, detonate, the remainder being scattered.

Some solutions of nitroglycerin (in ether, acetone, &c.) burn quietly, and the same is the case when it is held in solution or suspension in a colloid substance, as gelatinized guncotton, &c.

When the solution in the strong acid is allowed to stand, some nitric acid is first evolved, and as the temperature rises this is followed by a general decomposition of the substance, though not necessarily an explosive one.

The cornmercial product (which is known in Germany as "Kalkstickstof") contains from 14 to 22% of nitrogen, which is liberated as ammonia when the substance is treated with water; to this decomposition it owes its agricultural value.

A similar glass, if its cooling is greatly retarded, produces throughout its substance minute crystals of metallic copper, and closely resembles the mineral called avanturine.

Oxidation may be effected by the addition to the glass mixture of a substance which gives up oxygen at a high temperature, such as manganese dioxide or arsenic trioxide.

The leg is either pulled out from the substance of the base of the bowl, or from a small lump of glass added to the base.

This smooth surface is then brilliantly polished by the aid of friction with a rubbing tool covered with a soft substance like leather or felt and fed with a polishing material, such as rouge.

The story that Phoenician merchants found a glass-like substance under their cooking pots, which had been supported on blocks of natron, need not be discarded as pure fiction.

The peculiar merits of the Venetian manufacture are the elegance of form and the surprising lightness and thinness of the substance of the vessels produced.

Numerous methods have been given for the preparation of magnesium silicide, Mg 2 Si, in a more or less pure state, but the pure substance appears to have been obtained by P. Lebeau (Cornptes rendus, 1908, 146, p. 282) in the following manner.

Triethyl silicol, (C2H5),Si OH, is a true alcohol, obtained by condensing zinc ethyl with silicic ester, the resulting substance of composition, (C2H5)3 SiOC2H51 with acetyl chloride yielding a chloro-compound (C2H5)3SiC1, which with aqueous ammonia yields the alcohol.

All substance in nature falls into one of the two classes, solid and fluid; a solid substance, the land, for instance, as contrasted with a fluid, like water, being a substance which does not flow of itself.

A fluid, as the name implies, is a substance which flows, or is capable of flowing; water and air are the two fluids distributed most universally over the surface of the earth.

By a change of temperature and pressure combined, a substance can in general be made to pass from one state into another; thus by gradually increasing the temperature a solid piece of ice can be melted into the liquid state of water, and the water again can be boiled off into the gaseous state as steam.

Conversely, a combination of increased pressure and lowering of temperature will, if carried far enough, reduce a gas to a liquid, and afterwards to the solid state; and nearly every gaseous substance has now undergone this operation.

Every solid substance is found to be plastic more or less, as exemplified by punching, shearing and cutting; but the plastic solid is distinguished from the viscous fluid in that a plastic solid requires a certain magnitude of stress to be exceeded to make it flow, whereas the viscous liquid will yield to the slightest stress, but requires a certain length of time for the effect to be appreciable.

But when the smallest stress, if only continued long enough, will cause a perceptible and increasing change of form, the substance must be regarded as a viscous fluid, however hard it may be."

A fluid is a substance which yields continually to the slightest tangential stress in its interior; that is, it can be divided very easily along any plane (given plenty of time if the fluid is viscous).