Hardness Sentence Examples

The hardness came back into his eyes and he looked away.

You get used to knowing the different types of hardness and thickness.

The presence of the antimony in this alloy gives to it hardness, and the property of expanding on solidification, thus allowing a sharp cast of the letter to be taken.

The Dongola breed of horses is noted for its strength and hardness.

The problem is the extreme hardness of the ' cap ', thus the Kango.

The time required to make a herbal infusion depends on the hardness of the particular herb.

Its combination of permanent lubricity and high hardness enabled filters to be easily released and significantly extended the life of the molds.

Diamolith's 3000 Hv range and excellent lubricity will enable us to offer customers the optimum combination of hardness and low friction.

Alloying elements can be used to control the bulk microstructure of a steel and hence its hardness.

For this type of shading I use opacity 20% and hardness 0 %, with a brush size of between 8 and 15.

Some sensitivity coefficients can be calculated by taking partial derivatives of the equation defining the hardness value.

As a result of soil testing the STRI researched requirements for hardness, traction, ball rebound, sward height and grass cover.

Such properties in this case may include tensile strength, hardness, wear resistance and machinability among many others.

Smaller tools will include a hand lens, hardness tester, color char and magnet.

The chief crops of the farmer are wheat (which from its flinty hardness and full kernel is the specialty of the Canadian north-west), oats, barley and pease.

The hardness is 22 and the specific gravity 2.8.

The colour varies from yellowish or reddish to blackish-brown, and by transmitted light it is often blood-red; the streak is brownish-yellow; hardness, 5; specific gravity, 4.3.

If it contains a few parts of carbon per thousand, the annealing process, instead of softening the metal, gives it a "temper," meaning a higher degree of hardness and elasticity (see below).

The hardness (6-62) is the same as that of pyrites, and the specific gravity (4.8-4.9) as a rule rather less.

Aluminium oxide or alumina, Al 2 0 3, occurs in nature as the mineral corundum, notable for its hardness and abrasive power (see Emery), and in well-crystallized forms it constitutes, when coloured by various metallic oxides, the gem-stones, sapphire, oriental topaz, oriental amethyst and oriental emerald.

These movements, promoted by the councils of Constance and Basel, partook of the spirit of the time and were characterized by an extreme austerity of life and a certain hardness of spirit, and a sort of police regulation easily understandable at a time of reaction from grave abuses.

The results serve to show the great value of Australian timbers, and the comparisons made with the typical timbers of many other countries emphasize the fact that the Australian woods are equal to any in the world for hardness, strength and durability.

Be 100 percent sure of the hardness of your water so you don't spend too much getting one that won't soften the water efficiently or not spend enough so your water doesn't get softened.

The scientific name Cornus is Latin for 'horn', and is probably another reference to the hardness of the wood.

With a rating of 9 on the Mohs hardness scale, the only harder gem is the diamond.

Succinite has a hardness between 2 and 3,.

The substitution of steel for iron as the material for rails which made possible the axle loads and the speeds of Lto-day, and, by reducing the cost of maintenance, contributed enormously to the economic efficiency of railways, was one of the most important events in the history of railways, and a scarcely less important element of progressive economy has been the continued improvement of the steel rail in stiffness of section and in toughness and hardness of material.

It is an ironblack, opaque mineral, with metallic lustre; hardness about 6, sp. gr.

Marcianus, and the type is different from that of the Roman catacombs, the galleries being far larger (partly owing to the hardness of the limestone in which they are excavated), and having circular chambers at the points * of junction.

The wood used is generally that of the cherry-tree, sakura, which has a grain of peculiar evenness and hardness.

When not tarnished, the mineral has a silver-white colour with a tinge of red, and the lustre is metallic. Hardness 2-21; specific gravity 9-70-9.83.

Red clay is the deposit peculiar to the abysmal area; 70 carefully investigated samples collected by the " Challenger " came from an average depth of 2730 fathoms, 97 specimens collected by the " Tuscarora " came from an average depth of 2860 fathoms, and 26 samples obtained by the " Albatross " in the Central Pacific came from an average depth of 2620 fathoms. Red clay has not yet been found in depths less than 2200 fathoms. The main ingredient of the deposit is a stiff clay which is plastic when fresh, but dries to a stony hardness.

The characters of softness or hardness, dryness or moisture, &c., are taken account of in these classifications.

Such stones have been occasionally cut as lenses for microscopes, being recommended for such use by their high refractivity, weak dispersion and great hardness.

The ridges and intervening valleys, long parts of which have an approximately parallel trend from south-west to north-east, were formed by the erosion of folded sediments of varying hardness, the weak belts of rock being etched out to form valleys and the hard belts remaining as mountain ridges.

The metal produces an enormous number of useful alloys, some of which, containing only i or 2% of other metals, combine the lightness of aluminium itself with far greater hardness and strength.

Its hardness is about 6, and its specific gravity 4 9 to 5.2, being rather more than that of marcasite.

From copper-pyrites (chalcopyrite) iron-pyrites is distinguished by its superior hardness and by its paler colour.

But the invaluable and rather delicate art of tempering the hardened steel by a very careful and gentle reheating, which removes its extreme brittleness though leaving most of ifs precious hardness, needs such skilful handling that it can hardly have become known until very long after the art of hot-forging.

These include the austenitic or gamma non-magnetic manganese steel, already patented b y Robert Hadfield in 1883, the first important known substance which combined great malleableness with great hardness, and the martensitic or beta " high speed tool steel " of White and Taylor, which retains its hardness and cutting power even at a red heat.

Austenite may contain carbon in any proportion up to about 2.2 It is non-magnetic, and, when preserved in the cold either by quenching or by the presence of manganese, nickel, &c., it has a very remarkable combination of great malleability with very marked hardness, though it is less hard than common carbon steel is when hardened, and probably less hard than martensite.

The degree of hardening which the steel undergoes increases with its carbon-content, chiefly because, during sudden cooling, the presence of carbon acts like a brake to impede the transformations, and thus to increase the quantity of 0-iron caught in transit, but probably also in part because the hardness of this 0-iron increases with its carbon-content.

This brittleness has therefore in general to be mitigated or " tempered," unfortunately at the cost of losing part of the hardness proper, by reheating the hardened steel slightly,

But in most such cases, in spite of the annealing, this hardness is accompanied by a degree of brittleness too great for most purposes.

The general order of merit of a given variety or specimen of iron or steel may be measured by the degree to which it combines strength and hardness with ductility.

Nickel steel, which usually contains from 3 to 3.50% of nickel and about 0.25% of carbon, combines very great tensile strength and hardness, and a very high limit of elasticity, with great ductility.

But its great hardness is not materially affected by the rate of cooling.

It is used extensively for objects which require both hardness and ductility, such as rock-crushing machinery, railway crossings, mine-car wheels and safes.

Chrome steel, which usually contains about 2% of chromium and o 80 to 2% of carbon, owes its value to combining, when in the " hardened " or suddenly cooled state, intense hardness with a high elastic limit, so that it is neither deformed permanently nor cracked by extremely violent shocks.

The hardness of the hardened chrome steel resists the burglar's drill, and the ductility of the wrought iron the blows of his sledge.

Its specific gravity is 5.2, and its hardness 5.5 to 6.5.

Its specific gravity is 5.3 and its hardness 5.5 to 6.5.

Its streak is yellowish-black, its specific gravity 3.6 to 4.0, and its hardness 5 to 5.5.

Its specific gravity is 3.7 to 3.9, and its hardness 3.5 to 4.5.

Its specific gravity is 4.83 to 5.2, its hardness 6 to 6.5.

The impact face of these plates is given the intense hardness needed by being converted into high-carbon steel, and then hardened by sudden cooling.

Under these conditions the hardness, which is very extreme at the impact face, shades off toward the back, till at about quarter way from face to back all hardening ceases, and the rest of the plate is in a very strong, shock-resisting state.

For crushing certain kinds of rock, the hardness of which cast iron is capable really makes it more valuable, pound for pound, than steel.

Of these several qualities which cast iron may have, fluidity is given by keeping the sulphur-content low and phosphoruscontent high; and this latter element must be kept low if shock is to be resisted; but strength, hardness, endurance of shock, density and expansion in solidifying are controlled essentially by the distribution of the carbon between the states of graphite and cementite, and this in turn is controlled chiefly by the proportion of silicon, manganese and sulphur present, and in many cases by the rate of cooling.

Now how does it come about that the distribution of the carbon between these very unlike states determines the strength, hardness and many other valuable properties of the metal as a whole?

Above the diagram are given the names of the different classes of cast iron to which different stages in the change from graphite to cementite correspond, and above these the names of kinds of steel or cast iron to which at the corresponding stages the constitution of the matrix corresponds, while below the diagram are given the properties of the cast iron as a whole corresponding to these stages, and still lower the purposes for which these stages fit the cast iron, first because of its strength and shock-resisting power, and second because of its hardness.

Influence of the Constitution of Cast Iron on its Properties.- How should the hardness, strength and ductility, or rather shockresisting power, of the cast iron be affected by this progressive change from graphite into cementite ?

First, the hardness (VU) should increase progressively as the soft ferrite and graphite are replaced by the glass-hard cementite.

To sum this up, as graphite is replaced by carbon combined as cementite, the hardness, brittleness and density increase, and the expansion in solidification decreases, in both cases continuously, while the tensile strength increases till the combined carbon-content rises a little above I %, and then in turn decreases.

That strength is good and brittleness bad goes without saying; but here a word is needed about hardness.

The expense of cutting castings accurately to shape, cutting on them screw threads and what not, called " machining " in trade parlance, is often a very large part of their total cost; and it increases rapidly with the hardness of the metal.

The consummate hardness of the diamond, in spite of its high price, has made it most useful for purposes of grinding, polishing and drilling.

The majority of minerals are found commonly in masses which can with difficulty be recognized as aggregates of crystalline grains, and occur comparatively seldom as distinct crystals; but the diamond is almost always found in single crystals, which show no signs of previous attachment to any matrix; the stones were, until the discovery of the South African mines, almost entirely derived from sands or gravels, but owing to the hardness of the mineral it is rarely, if ever, water-worn, and the crystals are often very perfect.

It is the hardest known substance (though tantalum, or an alloy of tantalum now competes with it) and is chosen as io in the mineralogist's scale of hardness; but the difference in hardness between diamond (io) and corundum (9) is really greater than that between corundum (9) and talc (1); there is a difference in the hardness of the different faces; the Borneo stones are also said to be harder than those of Australia, and the Australian harder than the African, but this is by no means certain.

The specific gravity is 40, and the hardness 4.

Those are freely used.in the preparation of small tablets, compressed to such a condition of hardness as to resemble wood or stone, and commonly passed round as currency in certain districts of Russia.

It is rather softer and less dense than crystallized quartz, its hardness being about 6.5 and its specific gravity 2.6, the difference being probably due to the presence of a small amount of opaline silica between the fibres.

Formed mostly of horizontal strata of varying hardness, they present a series of terraces of minor plateaus, rising one above the other, and intersected by small ravines worn by the occasional rainstorms which burst in their neighborhood.

The hardness is 2 to 2.5 and the spec. gray.

But the dominant cause in the determination of the topographical prominences and depressions of the district has been the relative hardness and softness of the rocks.

The bands of massive grit and coarse greywacke, for example, break up into larger blocks and from their greater hardness are apt to project above the general surface of the other softer rocks.

Denudation has continued active ever since, and now, owing to greater hardness and consequent power of resistance, the glassy lava stands up as the prominent and picturesque ridge of the Scuir, while the basalts which formerly rose high above it have been worn down into terraced declivities that slope away from it to the sea.

The blocks are often not quite rectangular, and the courses sometimes change; but the general tendency is horizontal and the walls are not of remote antiquity, the irregularities in them being rather due to the hardness of the material employed, the rock of the hill itself.

It can seldom be obtained in large portions, and has the disadvantage of being apt to warp; its great hardness, however, renders it valuable for the manufacture of various articles, such as the cogs of mill-wheels, flails and mallets, and handles of hammers.

The great fluidity of bronze when melted, the slightness of its contraction on solidifying, together with its density and hardness, make it especially suitable for casting, and allow of its taking the impress of the mould with extreme sharpness and delicacy.

With repeated hammering, drawing out and annealing, it gains much in strength and toughness, and the addition of a very minute quantity of carbon converts it into steel, less tough, but of the keenest hardness.

Copper in its pure state may be worked by the same methods as bronze, but it is inferior to it in hardness, strength and beauty of surface.

The colour is iron-black and the lustre metallic; hardness 6, specific gravity 5.2.

It is rivalled in hardness by the kdyu tembesu.

The thread spun by the jenny could not, however, be used except as weft, being destitute of the firmness or hardness required in the longitudinal threads or warp. Arkwright supplied this deficiency by the invention of the spinning-frame, which spins a vast number of threads of any degree of fineness and hardness.

The bearing of the pivot is called a step or footstep. Pivots require great hardness, and are usually made of steel.

A thing is no longer, as Plato once thought, hot or hard or bright by partaking in abstract heat or hardness or brightness, but by containing within its own substance the material of these qualities, conceived as air-currents in various degrees of tension.

Fluor-spar has a hardness of 4, so that it is scratched by a knife, though not so readily as calcite.

The hardness of the crystallized haematite is about 6, and the specific gravity 5.2.

In hardness it is superior to gold, but inferior to copper.

Thus arsenic, antimony, bismuth, tin or zinc render the metal brittle, so that it fractures under a die or rolling mill; copper, on the other hand, increases its hardness, makes it tougher and more readily fusible.

The remarkable ovoid involucre of Coix, which becomes of stony hardness, white and polished (then known as " Job's tears," q.v.), is also a modified bract or leaf-sheath.

It is infusible before the gas blowpipe, but in the oxyhydrogen flame fuses to a clear colourless glass, which has a hardness of 5 and specific gravity 2.2.

At the base of the Chalk is the Chalk Marl, above this is the Totternhoe Stone, which, on account of its great hardness, usually stands out as a well-marked feature.

There is a hardness about the younger Horace which might have been, but is not made, imposing, and Sabine's effect on the action is quite out of proportion to the space she occupies.

Its hardness is greater than that of steel, so that a knife blade leaves a grey metallic streak when drawn across its surface.

Its great hardness also enables it to resist attrition.

The steel bronze of Colonel Franz Uchatius (1811-1881) consisted of copper alloyed with 8% of tin, the tenacity and hardness being increased by cold-rolling.

The bronze used for the British and French copper coinage consists of 95% copper, 4% tin and 1% zinc. Many copper-tin alloys employed for machinery-bearings contain a small proportion of zinc, which gives increased hardness.

The hardness is 3.5 and the specific gravity 5'63-5'73.

Seebeck found that the metals could be arranged in a Thermoelectric Series, in the order of their power when combined with any one metal, such that the power of any thermocouple p, composed of the metals A and B, was equal to the algebraic difference (p'-p") of their powers when combined with the standard metal C. The order of the metals in this series was found to be different from that in the corresponding Volta series, and to be considerably affected by variations in purity, hardness and other physical conditions.

Up to this period the age of the horse is clearly shown by the condition of dentition, and for some time longer indications can be obtained from the wear of the incisors, though this depends to a certain extent upon the hardness of the food or other circumstances.

The hardness is 31 and the specific gravity 3.7.

These families, however, do not appear to have had anything like their present importance in the temperate flora, though, as they are mainly herbaceous plants with fruits of moderate hardness, they may have decayed and left no trace.

The sources exhibit a very wide range of spectral hardness, with interstellar absorption identified as a major influence.

Sapphires are a precious form of the mineral corundum - second only to diamond in hardness.

Engineer units can increase the hardness of the battle command asset by constructing field fortifications.

The extra hardness caused the droplets to form spherical globules.

All who would be loyal to our Lord must expect to endure hardness for Him.

The difference in the shear modulus has been suggested as the main factor in determining the hardness of the multilayer system.

Unusually, it combines this hardness with a degree of toughness, so the deposit can stand up to high stress contact.

The " permanent hardness " given by sulfate, chloride or nitrate salts cannot be removed by boiling.

There is no maximum value for total hardness of water supplies.

Rockwell hardness The Vickers hardness scale is not the only scale used to measure hardness in metals.

Recently, with the introduction of instrumented indentation hardness, it has become possible to measure the indent under the applied force.

If the carbonate hardness is low, a small amount of new acid will make a large change to the body's pH.

In a tiled pool the calcium hardness should be kept above 200 parts per million.

Unexpectedly, the radiation hardness has been found to be worse than silicon under charged hadron irradiation.

The fatigue resistance can also be related to the surface hardness of the gear.

These effects of water hardness are not harmful to health.

The specially heat-treated cutting chamber has an increased hardness of 750 Vickers.

The real world thus arising consists only of diverse combinations of atoms, having the properties of magnitude, figure, weight and hardness, all other qualities being relative only to the sentient organism.

Thus an organized individual (tout organise) " is a composite body consisting of the original, or elementary, parts and of the matters which have been associated with them by the aid of nutrition "; so that, if these matters could be extracted from the individual (tout), it would, so to speak, become concentrated in a point, and would thus be restored to its primitive condition of a germ; " just as, by extracting from a bone the calcareous substance which is the source of its hardness, it is reduced to its primitive state of gristle or membrane."2 " Evolution " and " development " are, for Bonnet, synonymous terms; and since by " evolution " he means simply the expansion of that which was invisible into visibility, he was naturally led to the conclusion, at which Leibnitz had arrived by a different line of reasoning, that no such thing as generation, in the proper sense of the word exists in nature.

Yet it is in this stratum, and in this alone, that the catacombs are constructed; their engineers avoiding with equal care the solid stone of the tufa litoide and the friable pozzolana, and selecting the stratum of medium hardness, which enabled them to form the vertical walls of their galleries, and to excavate the loculi and cubicula without severe labour and also without fear of their falling in.

Hardness and Chemical Stability.-These properties contribute to the durability of lenses, and are specially desirable in the outer members of lens combinations which are likely to be subjected to frequent handling or are exposed to the weather.

Tourmaline has a hardness of 7.5 on the Moh's scale and is found in Africa, Madagascar, Brazil, United States of America, Mexico, Myanmar and Sri Lanka.

Although the hardness is a 6 or 7, they will break easily if struck with force.

Color and hardness can both be affected by the blends karat measurements represent.

These blended waxes combine the ease of use of soy wax with the hardness and versatility of paraffin wax, and can be used in any type of candle.

Its hardness and durability make its care similar to diamonds, such as storing it away from other gems to prevent accidental scratches and avoiding harsh cleaning chemicals.

Though the stones are laboratory-created, they are of exceedingly high quality, often ranking at the same level or higher than natural gems in terms of hardness, sparkle, and durability.

Both natural and lab-created stones have the same hardness, specific gravity, refractive index and dispersion factor."

Because of their hardness, ruby rings should be stored separately from other jewelry so they do not inadvertently scratch or nick other pieces.

Colored diamonds have exactly the same features as white diamonds, which means they are of the same hardness and strength.

Diamonds are gauged for hardness based on the Mohs hardness scale of one to ten with ten being the hardest substance, and Herkimer diamonds rate higher than standard quartz, though they are softer than genuine diamonds.

Colored diamonds have exactly the same features as white diamonds, this means that they are of the same hardness and strength.

The hardness should not vary much based on the color of the gold.

Brown colored stones have the same hardness as white and are rated based on the color intensity.

This is necessary to achieve the proper balance of alkalinity, pH, chlorine and the calcium hardness of the pool water.

Granite is one of the hardest kitchen countertop materials and it ranks as a seven out of 10 on the Moh's hardness scale.

You may have chosen granite because of its hardness and durability, but this material is more porous than marble.

Instead of harmful chemicals, we use protein for strength, calcium for hardness, and ProVitamin B5 for flexibility.

But this " critical value " of the force is found to depend in an unexpected manner upon the hardness of the steel; the critical value diminishes as the hardness becomes greater up to a certain point, corresponding to a yellow temper, after which it increases and with the hardest steel becomes very high.

Hence the changes of volume undergone by a given sample of wrought iron under increasing magnetization must depend largely upon the state of the metal as regards hardness; there may be always contraction, or always expansion, or first one and then the other.

For building and miscellaneous purposes, in addition to the rare woods above named, there are cedars (used in great quantities for cigar boxes); the pine, found only in the W., where it gives its name to the Isle of Pines and the province of Pinar del Rio; various palms; oaks of varying hardness and colour, &c. The number of alimentary plants is extremely great.

Semitransparency, brilliancy and hardness are, however, also essentials.

It is certain that the structure existing in the alloy is closely connected with the mechanical properties, such as hardness, toughness, rigidity, and so on, that make particular alloys valuable in the arts, and many efforts have been made to trace this connexion.

The difference between softness and hardness in ordinary steel is due to the permanence of a solid solution of carbon in iron if the steel has been chilled or very rapidly cooled, while if the steel is slowly cooled this solid solution breaks up into a minute complex of two substances which is called pearlite.

The maximum hardness is from 2.5 to 3 in anthracite and hard bituminous coals, but considerably less in lignites, which are nearly as soft as rotten wood.

The hardness is 51-6, and the specific gravity 5.9-6.2.

An important character, and one by which the mineral may always be recognized, is the perfect cubical cleavage, on which the lustre is brilliant and metallic. The colour of the mineral and of its streak is lead-grey; it is opaque; the hardness is 2 2 and the specific gravity 7.5.

Its hardness is rather above 5, and its specific gravity varies from 3.5 to 4.

They have the property of entering into chemical combination with the lime, forming a hard setting compound, and increasing the hardness of the resulting concrete.

When quite pure it is somewhat harder than tin, and its hardness is considerably increased by rolling.

Then the boy returned to one of the upper rooms, and in spite of the hardness of the glass bench was soon deep in slumberland.

The heat of his bare chest beneath her hands and the hardness of his arousal against her belly made need roar to life within her.

The iron-bark of the eastern coast uplands is well known (Eucalyptus sideroxylon), and is so called from the hardness of the wood, the bark not being remarkable except for its rugged and blackened aspect.

The I heart-wood ceases to be of any use to the tree except as a support, but owing to its dryness and hardness it alone is of much use for industrial purposes.

The great hardness of teak is due to the silica deposited in the heart-wood, and the special coloring matters of various woods, such as satinwood, ebony, &c., are confined to the heart-wood.

When the waters evaporate in the summer they leave a clay bed of remarkable hardness, which is sometimes encrusted with saline matter of a snowy whiteness and dazzles the eyes of the traveller.

The hardness is 2, and the specific gravity 2 I.

Hauran southward forms the main watershed of the peninsula is covered in places by deep beds of lava, which from their hardness have preserved the underlying sandstones from degradation, and now stand up consider ably above the general level.

A greater hardness is due to the presence of earthy impurities.

Notwithstanding its hardness it has been sometimes engraved as a gem.

There are certain instances in his life which, taken by themselves, show a hardness in treating individuals who would not obey; but as a rule, he tempered his authority to the capacity of those with whom he had to deal.

The experiments were not sufficiently numerous to indicate whether, as is possible, there is a critical degree of hardness for which the height of the elongation curve is a maximum.

In the alluvial deposits the associated minerals are chiefly those of great density and hardness, such as platinum, osmiridium and other metals of the platinum group, tinstone, chromic, magnetic and brown iron ores, diamond, ruby and sapphire, zircon, topaz, garnet, &c. which represent the more durable original constituents of the rocks whose distintegration has furnished the detritus.

According to lapidaries the hardness of sapphire slightly exceeds that of ruby, and it is also rather denser.

Although it contains a higher percentage of metal (5 2.9%) than any other natural compound, it is not at present employed as an ore, not only because it is so hard as to be crushed with difficulty, but also because its very hardness makes it valuable as an abrasive.

The territories of the Gran Chaco, however, are covered with a characteristic tropical vegetation, in which the palm predominates, but intermingled south of the Bermejo with heavy growths of algarrobo, quebracho-colorado, urunday (Astronium fraxinifolium), lapacho (Tecoma curialis) and palosanto (Guayacum officinalis), all esteemed for hardness and fineness of grain.

During the three years he held this position he carried out researches on the contact of elastic solids, hardness, evaporation and the electric discharge in gases, the last earning him the special commendation of Helmholtz.

There is still controversy as to what degree of hardness, or (which is nearly the same thing) what percentage of carbon, can be permitted with safety in steel for structures.

His warm hands covered hers and she could feel the hardness of his chest muscles on her back as he guided her arms in a smooth swing.

Boron dissolves in molten aluminium, and on cooling, transparent, almost colourless crystals are obtained, possessing a lustre, hardness and refractivity near that of the diamond.

The hardness ranges from about I to 2, and the sp.gr.

Carbon is the important element in controlling hardness, and the amount present is in general higher in the United States than in Great Britain.

A high silica-content tends towards both hardness and chemical stability, and this can be further increased by the addition of small proportions of boric acid; in larger quantities, however, the latter constituent produces the opposite effect.

The shape of the hills and ridges is necessarily influenced by the inclination of the strata, by the relative hardness of different rock-beds, and by the presence of folds and fissures and other lines of weakness.

The hardness is 2 -3; smooth cleavage surfaces can be just scratched with the finger-nail.

Some experiments were next undertaken with the view of ascertaining how far magnetic changes of length in iron were dependent upon the hardness of the metal, and the unexpected result was arrived at that softening produces the same effect as tensile stress; it depresses the elongation curve, diminishing the maximum extension, and reducing the " critical value " of the magnetizing force.

Such an alloy can be cast like ordinary bronze, but excels the latter in hardness, elasticity, toughness and tensile strength.

Considerations of growth determine to a great extent the hardness or softness, and strength or weakness, of the fibre, and thus, indirectly, whether the cotton is suitable for warp or weft.

For example, the physicist determines the density, elasticity, hardness, electrical and thermal conductivity, thermal expansion, &c.; the chemist, on the other hand, investigates changes in composition, such as may be effected by an electric current, by heat, or when two or more substances are mixed.

They were certainly originally stone-quarries, and the hardness of the rock has made the construction practicable of wide, lofty of corridors and spacious halls, very unlike the narrow galleries and contracted chambers in the Roman cemeteries.

Then her attention was called to the hardness of the one ball and the softness of the other, and she learned SOFT and HARD.

They are full of both grace and individuality; the features show excellent draughtsmanship; and the flesh-painting is firm and sound in method, though frequently tending a little to hardness and opacity.

Most natural waters contain it dissolved in carbonic acid; this confers "temporary hardness" on the water.

By the "hardness" of a metal we mean the resistance which it offers to the file or engraver's tool Taking it in this sense, it does not necessarily measure, e.g.