How to use Calcium in a sentence
The product is dissolved in water, and the calcium haloid estimated in the usual way.
Ammonium carbonate is added to the filtrate; this precipitates calcium, strontium and barium.
Near the station, below the town, are factories of india-rubber and calcium carbide.
Coral reefs remove calcium from solution in the sea on a vast scale.
Beryllium and magnesium are permanent in dry air; calcium, strontium and barium, however, oxidize rapidly on exposure.Advertisement
If the acid has been swallowed, wash out the stomach and give chalk, the carbolate of calcium being insoluble.
All these animals have calcareous skeletons or shells of some form and they secrete the calcium from its solution as sulphate, converting it into carbonate.
The colloidal particles are electrically charged and become discharged by the ions of sodium, magnesium and calcium present in the sea-water.
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 source of the carbon of organic tissues is carbonic acid; that of the nitrogen in the proteids is the nitrates, nitrites and salts of ammonia dissolved in sea-water; the material of the shells or other skeletons is the silica, phosphate and calcium of the salts of sea-water (and, in rare cases, the salts of strontium).Advertisement
The water of the ocean is usually nearly saturated with calcium salts, which must continually be removed since they are always being added in the water brought down from the land.
The water in shallow seas, off the shores of islands or in lagoons, is saturated with calcium bicarbonate and if the amount of carbonic acid in solution be reduced by any means, normal carbonate must be precipitated.
Therefore a reduction in the partial pressure of the gas in the atmosphere, or a rise in the temperature of the water, or a violent agitation of the sea itself, will lead to precipitation of calcium carbonate.
It is a centre of the iron and steel industries, producing principally cast steel, cast iron, iron pipes, wire and wire ropes, and lamps, with tin and zinc works, coal-mining, factories for carpets, calcium carbide and paper-roofing, brickworks and breweries.
Of the calcium orthophosphates, the normal salt, Ca3(P04)2, is the most important.Advertisement
There are, therefore, a number of agencies, all of which operate in shoal waters on the lee side of islands, or in shallow lagoons in such regions as the Bahamas, and the result of all these is to throw down calcium carbonate from solution in sea-water as minute needle-shaped crystals or little balls of aragonite.
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.
Determinations have been made with calcium oxalate, CaC 2 04+H 2 0, which is easily decomposed by acids, oxalic acid and a soluble calcium salt being formed.
The acid employed may be hydrochloric, which gives the best results, or sulphuric, which is used in Germany; sulphuric acid is more readily separated from the product than hydrochloric, since the addition of powdered chalk precipitates it as calcium sulphate, which may be removed by a filter press.
The dissolved salts (potassium, sodium, ammonium, calcium, magnesium, &c.) of the latex are generally nearly entirely absent from the wellprepared rubber.Advertisement
In making up a charge, the ores and fluxes, whose chemical compositions have been determined, are mixed so as to form out of the components, not to be reduced to the metallic or sulphide state, typical slags (silicates of ferrous and calcium oxides, incidentally of aluminium oxide, which have been found to do successful work).
The word "pure" is emphasized because experience shows that the presence in a water of even small proportions of calcium bicarbonate or sulphate prevents its action on lead.
It forms crystallizable salts with potassium and calcium hydrates, and functions as a weak acid forming salts named plumbates.
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.
This solution is allowed to stand for some time (in order that any calcium sulphate and basic ferric sulphate may separate), and is then evaporated until ferrous sulphate crystallizes on cooling; it is then drawn off and evaporated until it attains a specific gravity of 1.40.Advertisement
When cryolite is used for the preparation of alum, it is mixed with calcium carbonate and heated.
It is manufactured by heating pitchblende with lime, treating the resulting calcium uranate with dilute sulphuric acid, and adding sodium carbonate in excess.
The distillate is purified by treatment with lime and calcium chloride, and subsequent distillation.
The potash and soda is then gradually replaced by calcium to.
Calcium or potassium sulphides and potassium hydrosulphides completely reduce nitroglycerin to glycerin, some of the sulphur being oxidized and some precipitated.
Calcium cyanamide has assumed importance in agriculture since the discovery of its economic production in the electric furnace, wherein calcium carbide takes up nitrogen from the atmosphere to form the cyanamide with the simultaneous liberation of carbon.
It appears that with soils which are not rich in humus or not deficient in lime, calcium cyanamide is almost as good, nitrogen for nitrogen, as ammonium sulphate or sodium nitrate; but it is of doubtful value with peaty soils or soils containing little lime, nor is it usefully available as a top-dressing or for storing.
The refractive indices of all glasses at present available lie between 1.46 and 1 90, whereas transparent minerals are known having refractive indices lying considerably outside these limits; at least one of these, fluorite (calcium fluoride), is actually used by opticians in the construction of certain lenses, so that probably progress is to be looked for in a considerable widening of the limits of available optical materials; possibly such progress may lie in the direction of the artificial production of large mineral crystals.
Silicon fluoride, SiF4, is formed when silicon is brought into contact with fluorine (Moissan); or by decomposing a mixture of acid potassium fluoride and silica, or of calcium fluoride and silica with concentrated sulphuric acid.
Many are found as minerals, the more important of such naturally occurring carbonates being cerussite (lead carbonate, PbC03), malachite and azurite (both basic copper carbonates), calamine (zinc carbonate, ZnCO 3), witherite (barium carbonate, BaCO 3), strontianite (strontium carbonate, SrC03), calcite (calcium carbonate, CaC03), dolomite (calcium magnesium carbonate, CaCO 3 MgCO 3), and sodium carbonate, Na 2 CO 3.
Water, at ordinary or slightly elevated temperatures, is decomposed more or less readily, with evolution of hydrogen gas and formation of a basic hydrate, by (I) potassium (formation of KHO), sodium (NaHO), lithium (LiOH), barium, strontium, calcium (BaH 2 O 2, &c.); (2) magnesium, zinc, manganese (MgO 2 H 2, &c.).
Somewhat less volatile than the last-named group are the chlorides (MC1 2) of barium, strontium and calcium.
Chalk consists, when quite pure, of calcium carbonate (CaC03), a white solid substance useful in small amounts as a plant foodmaterial, though in excess detrimental to growth.
It has been found by experiment that plants need for their nutritive process and their growth, certain chemical elements, namely, carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorus, potassium, magnesium, calcium and iron.
The sulphur exists in the soil chiefly in the form of sulphates of magnesium, calcium and other metals; the phosphorus mainly as phosphates of calcium, magnesium and iron; the potash, soda and other bases as silicates and nitrates; calcium and magnesium carbonates are also common constituents of many soils.
The material which chemists call calcium carbonate is met with in a comparatively pure state in chalk.
The resulting white product is termed calcium oxide lime, burnt lime, quicklime, cob lime, or caustic lime.
This substance absorbs and combines with water very greedily, at the same time becoming very hot, and falling into a fine dry powder,' calcium hydroxide or slaked lime, which when left in the open slowly combines with the carbon dioxide of the air and becomes calcium carbonate, from which we began.
Wall-saltpetre or lime saltpetre, calcium nitrate, Ca(N03)2, is found as an efflorescence on the walls of stables; it is now manufactured in large quantities by fixing atmospheric nitrogen, i.e.
Second in importance is the carbonate, calamine (q.v.) or zinc spar, which at one time was the principal ore; it almost invariably contains the carbonates of cadmium, iron, manganese, magnesium and calcium, and may be contaminated with clay, oxides of iron, galena and calcite; "white calamine" owes its colour to much clay; "red calamine" to admixed iron and manganese oxides.
Neither mechanical nor magnetic concentration can effect much in the way of separation when, as in many complex ores, carbonates of iron, calcium and magnesium replace the isomorphous zinc carbonate, when some iron sulphide containing less sulphur than pyrites replaces zinc sulphide, and when gold and silver are contained in the zinc ore itself.
There is a third class of operations, exemplified by the manufacture of calcium carbide, in which electricity is employed.
When prolonged heating is required at very high temperatures it is found necessary to line the furnace-cavity with alternate layers of magnesia and carbon, taking care that the lamina next to the lime is of magnesia; if this were not done the lime in contact with the carbon crucible would form calcium carbide and would slag down, but magnesia does not yield a carbide in this way.
The arc furnaces now widely used in the manufacture of calcium carbide on a large scale are chiefly developments of the Siemens furnace.
Calcium carbide, graphite, phosphorus and carborundum are now extensively manufactured by the operations outlined above.
Methods have also been discovered for the electrolytic manufacture of calcium, which have had the effect of converting a laboratory curiosity into a product of commercial importance.
The Alexandrians prepared oil of turpentine by distilling pine-resin; Zosimus of Panopolis, a voluminous writer of the 5th century A.D., speaks of the distillation of a "divine water" or "panacea" (probably from the complex mixture of calcium polysulphides, thiosulphate, &c., and free sulphur, which is obtained by boiling sulphur with lime and water) and advises "the efficient luting of the apparatus, for otherwise the valuable properties would be lost."
Dry distillation is extremely wasteful even when definite substances or mixtures, such as calcium acetate which yields acetone, are dealt with, valueless by-products being obtained and the condensate usually requiring much purification.
Strontium chloride, SrC1 2.6H 2 O, is obtained by dissolving the carbonate in hydrochloric acid, or by fusing the carbonate with calcium chloride and extracting the melt with water.
It resembles calcium carbide, decomposing rapidly with water, giving acetylene.
Hermite, which consisted in the production of bleach-liquors by the electrolysis (according to the 1st edition of the 1884 patent) of magnesium or calcium chloride between platinum anodes carried in wooden frames, and zinc cathodes.
The calcium salts distilled with calcium formate yield aldehydes r distilled with soda-lime, ketones result.
It is found in the form of its acid potassium salt in many plants, especially in wood-sorrel (Oxalis acetosella) and in varieties of Rumex; as ammonium salt in guano; as calcium salt in rhubarb root, in various lichens and in plant cells; as sodium salt in species of Salicornia and as free acid in varieties of Boletus.
In this process cellulose (in the form of sawdust) is made into a stiff paste with a mixture of strong caustic potash and soda solution and heated in flat iron pans to 20o-250 C. The somewhat dark-coloured mass is lixiviated with a small amount of warm water in order to remove excess of alkali, the residual alkaline oxalates converted into insoluble calcium oxalate by boiling with milk of lime, the lime salt separated, and decomposed by means of sulphuric acid.
Direct application into the widened wound of calcium hypochlorite, i.e.
Calcium chloride must not be used, since it forms a crystalline compound with alcohol.
At the same time any lead, calcium, barium and strontium present are precipitated as sulphates; it is therefore advantageous to remove these metals by the preliminary addition of sulphuric acid, which also serves to keep any basic iron salts in solution.
The main exports were asphalt and calcium carbide.
In a smaller degree these alkaline properties are shared by the less soluble hydrates of the "metals of the alkaline earths," calcium, barium and strontium, and by thallium hydrate.
Recent limestones are being produced in this way and also in some places by the precipitation of calcium carbonate by sodium or ammonium carbonate which has been carried into the sea or formed by organisms. The precipitated carbonate may agglomerate on mineral or organic grains which serve as nuclei, or it may form a sheet of hard deposit on the bottom as occurs in the Red Sea, off Florida, and round many coral islands in the Pacific. Only the sand and the finest-grained sediments of the shore zone are carried outwards over the continental shelf by the tides or by the reaction-currents along the bottom set up by on-shore winds.
The most abundant of the terrigenous materials are the finest particles of clay and calcium carbonate as well as fragments derived from land vegetation, of which twigs, leaves, &c., may form a perceptible proportion as far as 200 m.
The proportion of calcium carbonate varies greatly according to the amount of foraminifera and other calcareous organisms which it contains.
When the proportion of calcium carbonate in the blue mud is considerable there results a calcareous ooze, which when found on the continental slope and in enclosed seas is largely composed of remains of deep-sea corals and bottom-living foraminif era, pelagic organisms including pteropods being less frequently represented.
The bottom of the Black Sea is covered by a stiff blue mud in which Sir John Murray found much sulphide of iron,' grains or needles of pyrites making up nearly 50% of the deposit, and there are also grains of amorphous calcium carbonate evidently precipitated from the water.
In the Red Sea the " Pola " expedition discovered a calcareous .00ze similar to that of the Mediterranean, and the formation of a stony crust by precipitation of calcium and magnesium carbonates may be recognized as giving origin to a recent dolomite.
It is a remarkable geographical fact that on the rises and in the basins of moderate depth of the open ocean the organic oozes preponderate, but in the abysmal depressions below 2500 or 3000 fathoms, whether these lie in the middle or near the edges of the great ocean spaces, there is found only the red clay, with a minimum of calcium carbonate, though sometimes with a considerable admixture of the siliceous remains of radiolarians.
Murray and Renard define globigerina ooze as containing at least 30% of calcium carbonate, in which the remains of pelagic (not benthonic) foraminifera predominate and in which remains of pelagic mollusca such as pteropods and heteropods, ostracodes and also coccoliths (minute calcareous algae) may also occur.
A small proportion of organic matter including the fat globules of the plankton is mixed with the calcium carbonate, the amount according to Giimbel's analysis being about 1 part in 1000.
A very interesting feature is the small proportion of calcium carbonate, the amount present being usually less as the depth is greater; red clay from depths exceeding 3000 fathoms does not contain so much as 1% of calcareous matter.
It is, however, a curious question how, considering the increase of carbonic acid by the decomposition of organic bodies and possible submarine exhalations of volcanic origin, the water has not in some places become saturated and a precipitate of amorphous calcium carbonate formed in the deepest water.
The elements in addition to oxygen which exist in largest amount in sea salt are chlorine, bromine, sulphur, potassium, sodium, calcium and magnesium.
Magnesium sulphate amounts to 4.7% of the total salts of sea-water according to Dittmar, but to 23.6% of the salts of the Caspian according to Lebedinzeff; in the ocean magnesium chloride amounts to 10.9% of the total salts, in the Caspian only to 4.5%; on the other hand calcium sulphate in the ocean amounts to 3.6%, in the Caspian to 6.9 This disparity makes it extremely difficult to view ocean water as merely a watery extract of the salts existing in the rocks of the land.
Hackspill (Comptes Rendus, 5905, 141, p. 101) finds that metallic caesium can be obtained more readily by heating the chloride with metallic calcium.
Wohler first made calcium carbide, and found that water decomposed it into lime and acetylene.
Moissan in France that if lime and carbon be fused together at the temperature of the electric furnace, the lime is reduced to calcium, which unites with the excess of carbon present to form calcium carbide.
In the manufacture of calcium carbide in the electric furnace, lime and anthracite of the Manufac- highest possible degree of purity are employed.
The two principal processes utilized in making calcium carbide by electrical power are the ingot process and the tapping process.
Under the same conditions it becomes incandescent in the vapour of sulphur, yielding calcium sulphide and carbon disulphide; the vapour of phosphorus will also unite with it at a red heat.
Acted upon by water it is at once decomposed, yielding acetylene and calcium hydrate.
Pure crystalline calcium carbide yields 5.8 cubic feet of acetylene per pound at ordinary temperatures, but the carbide as sold commercially, being a mixture of the pure crystalline material with the crust which in the electric furnace surrounds the ingot, yields at the best 5 cubic feet of gas per pound under proper conditions of generation.
The formation of hydrogen is caused by small traces of metallic calcium occasionally found free in the carbide, and cases have been known where this was present in such quantities that the evolved gas contained nearly 20% of hydrogen.
This takes place when in the manufacture of the carbide the material is kept too long in contact with the arc, since this overheating causes the dissociation of some of the calcium carbide and the solution of metallic calcium in the remainder.
Phosphuretted hydrogen, one of the most important impurities, which has been blamed for the haze formed by the combustion of acetylene under certain conditions, is produced by the action of water upon traces of calcium phosphide found in carbide.
In the generation of acetylene from calcium carbide and water, all that has to be done is to bring these two compounds into contact, when they mutually react upon each other with the formation of lime and acetylene, while, if there be sufficient water present, the lime combines with it to form calcium hydrate.
It is found that the ingot of calcium carbide formed in the furnace, although itself consisting of pure crystalline calcium carbide, is nearly always surrounded by a crust which contains a certain proportion of imperfectly converted constituents, and therefore gives a lower yield of acetylene than the carbide itself.
Calcium carbide, as formed in the electric furnace, is a beautiful crystalline semi-metallic solid, having a density of 2.22, and showing a fracture which is often shot with iridescent "non-automatic."
Dr Wolff employs purifiers in which the gas is washed with water containing calcium chloride, and then passed through bleaching-powder solution or other oxidizing material.
Alcohol is produced by fermentation from vegetable substances containing starch or sugar, from fermentable sugars produced by the hydrolysis of cellulosic bodies, and synthetically from calcium carbide and from the ethylene contained in coal and coke-oven gases.
The distillate is treated with anhydrous calcium chloride, the crystalline compound formed with the alcohol being separated and decomposed by redistilling with water.
Its compound with calcium chloride has the formula CaC1 2.4CH 3.
In solar physics Huggins suggested a spectroscopic method for viewing the red prominences in daylight; and his experiments went far towards settling a much-disputed question regarding the solar distribution of calcium.
This circumstance appeared so anomalous that some astronomers doubted whether the surviving lines were really due to calcium; but Sir William and Lady Huggins (née Margaret Lindsay Murray, who, after their marriage in 1875, actively assisted her husband) successfully demonstrated in the laboratory that calcium vapour, if at a sufficiently low pressure, gives under the influence of the electric discharge precisely these lines and no others.
It may contain from 55 to 62% of calcium phosphate, with about 7% of magnesium phosphate.
In combination with calcium sulphate, it constitutes the mineral glauberite or brongniartite, Na2S04 CaS041 which assumes forms belonging to the monoclinic system and occurs in Spain and Austria.
There are wood-pulp factories (one worked by an English company employing over 1000 hands), factories for calcium carbide (used for manufacturing acetylene gas), paper and aluminium; and spinning and weaving mills.
The drug, along with gum, fatty oils, and malates of magnesium and calcium, contains also about 1% of cubebic acid, and about 6% of a resin.
Other constituents are cholesterol (0.461.32%), traces of calcium, magnesium, sodium, chlorine and bromine, and various aliphatic amines which are really secondary products, being formed by the decomposition of the cellular tissue.
Calcium oxide or lime has been known from a very remote period, and was for a long time considered to be an elementary or undecomposable earth.
His attempts at isolating this metal were not completely successful; in fact, metallic calcium remained a laboratory curiosity until the beginning of the 10th century.
Davy, inspired by his successful isolation of the metals sodium and potassium by the electrolysis of their hydrates, attempted to decompose a mixture of lime and mercuric oxide by the electric current; an amalgam of calcium was obtained, but the separation of the mercury was so difficult that even Davy himself was not sure as to whether he had obtained pure metallic calcium.
Electrolysis of lime or calcium chloride in contact with mercury gave similar results.
Henri Moissan obtained the metal of 99% purity by electrolysing calcium iodide at a low red heat, using a nickel cathode and a graphite anode; he also showed that a more convenient process consisted in heating the iodide with an excess of sodium, forming an amalgam of the product, and removing the sodium by means of absolute alcohol (which has but little action on calcium), and the mercury by distillation.
The electrolytic isolation of calcium has been carefully investigated, and this is the method followed for the commercial production of the metal.
These chemists electrolyse either pure calcium chloride, or a mixture of this salt with fluorspar, in a graphite vessel which servos as the anode.
On electrolysis a layer of metallic calcium is formed at the lower end of this rod on the surface of the electrolyte; the rod is gradually raised, the thickness of the layer increases, and ultimately a rod of metallic calcium, forming, as it were, a continuation of the iron cathode, is obtained.
This is the form in which calcium is put on the market.
An idea as to the advance made by this method is recorded in the variation in the price of calcium.
A freshly prepared surface of the metal closely resembles zinc in appearance, but on exposure to the air it rapidly tarnishes, becoming yellowish and ultimately grey or white in colour owing to the formation of a surface layer of calcium hydrate.
A faint smell of acetylene may be perceived during the oxidation in moist air; this is probably due to traces of calcium carbide.
It is rapidly acted on by water, especially if means are taken to remove the layer of calcium hydrate formed on the metal; alcohol acts very slowly.
Whereas calcium chloride, bromide, and iodide are deliquescent solids, the fluoride is practically insoluble in water; this is a parallelism to the soluble silver fluoride, and the insoluble chloride, bromide and iodide.
Calcium fluoride, CaF2, constitutes the mineral fluor-spar, and is prepared artificially as an insoluble white powder by precipitating a solution of calcium chloride with a soluble fluoride.
Calcium iodide and bromide are white deliquescent solids and closely resemble the chloride.
Calcium carbonate, CaCO 3, is of exceptionally wide distribution in both the mineral and animal kingdoms. It constitutes the bulk of the chalk deposits and limestone rocks; it forms over one-half of the mineral dolomite and the rock magnesium limestone; it occurs also as the dimorphous minerals aragonite (q.v.) and calcite (q.v.).
Calcium carbonate is obtained as a white precipitate, almost insoluble in water (1 part requiring Io,000 of water for soluticn), by mixing solutions of a carbonate and a calcium salt.
Calcium nitrate, Ca(N0,)2.4H20, is a highly deliquescent salt, crystallizing in monoclinic prisms, and occurring in various natural waters, as an efflorescence in limestone caverns, and in the neighbourhood of decaying nitrogenous organic matter.
A basic nitrate, Ca(NO 3)2 Ca(OH) 2.3H 2 0, is obtained by dissolving calcium hydroxide in a solution of the normal nitrate.
Calcium phosphide, Ca 3 P 2, is obtained as a reddish substance by passing phosphorus vapour over strongly heated lime.
The mineral brushite, CaHPO 4.2H 2 0, which is isomorphous with the acid arsenate pharmacolite, CaHAs04.2H20, is an acid phosphate, and assumes monoclinic forms. The normal salt may be obtained artificially, as a white gelatinous precipitate which shrinks greatly on drying, by mixing solutions of sodium hydrogen phosphate, ammonia, and calcium chloride.
The artificial manure known as "superphosphate of lime" consists of this salt and calcium sulphate, and is obtained by treating ground bones, coprolites, &c., with sulphuric acid.
It is obtained as rhombic plates by mixing dilute solutions of calcium chloride and sodium phosphate, and passing carbon dioxide into the liquid.
Calcium monosulphide, CaS, a white amorphous powder, sparingly soluble in water, is formed by heating the sulphate with charcoal, or by heating lime in a current of sulphuretted hydrogen.
Calcium sulphite, CaSO 3, a white substance, soluble in water, is prepared by passing sulphur dioxide into milk of lime.
Calcium silicates are exceptionally abundant in the mineral kingdom.
Calcium metasilicate, CaSiO 3, occurs in nature as monoclinic crystals known as tabular spar or wollastonite; it may be prepared artificially from solutions of calcium chloride and sodium silicate.
Detection and Estimation.-Most calcium compounds, especially when moistened with hydrochloric acid, impart an orange-red colour to a Bunsen flame, which when viewed through green glass appears to be finch-green; this distinguishes it in the presence of strontium, whose crimson coloration is apt to mask the orange-red calcium flame (when viewed through green glass the strontium flame appears to be a very faint yellow).
In the spectroscope calcium exhibits two intense lines-an orange line (a), (X 6163), a green line (a), (X 4229), and a fainter indigo line.
Calcium is not precipitated by sulphuretted hydrogen, but falls as the carbonate when an alkaline carbonate is added to a solution.
Sulphuric acid gives a white precipitate of calcium sulphate with strong solutions; ammonium oxalate gives calcium oxalate, practically insoluble in water and dilute acetic acid, but readily soluble in nitric or hydrochloric acid.
Calcium is generally estimated by precipitation as oxalate which, after drying, is heated and weighed as carbonate or oxide, according to the degree and duration of the heating.
Ammonia gas has the power of combining with many substances, particularly with metallic halides; thus with calcium chloride it forms the compound CaCl 2.8NH 3, and consequently calcium chloride cannot be used for drying the gas.
Ammonium chlorate, NH 4 C10 3, is obtained by neutralizing chloric acid with either ammonia or ammonium carbonate, or by precipitating barium, strontium or calcium chlorates with ammonium carbonate.
The atomic weight of fluorine has been determined by the conversion of calcium, sodium and potassium fluorides into the corresponding sulphates.
Hydrated sulphates occur at several localities in the province of Madrid and in other provinces of Spain, and at Miihlingen in Aargau, and copious deposits of glauberite, the double sulphate of sodium and calcium, are met with in the salt-mines of Villarrubia in Spain, at Stassfurt, and in the province of Tarapaca, Chile, &c. A native nitrate of soda is obtained in great abundance in the district of Atacama and the province of Tarapaca, and is imported into Europe in enormous quantities as cubic nitre for the preparation of saltpetre.
It is a very impure form of carbon., containing on the average about 80% of calcium phosphate.
The remaining mud of calcium carbonate and hydrate is washed, by decantation, with small instalments of hot water to recover at least part of the alkali diffused throughout it, but this process must not be continued too long or else some of the lime passes into solution.
If the original solution contained the chlorides of magnesium or calcium or sulphate of potassium all impurities remain in the mother-liquor (the sulphur as KHS04), and can be removed by washing the precipitate with strong hydrochloric acid.
His next discovery, in 1781, was the composition of the mineral tungsten, since called scheelite (calcium tungstate), from which he obtained tungstic acid.
Stas recommends solution of the iodine in potassium iodide and subsequent precipitation by the addition of a large excess of water, the precipitate being washed, distilled in steam, and dried in vacuo over solid calcium nitrate, and then over solid caustic baryta.
The most commonly used salt is the iodide of potassium; the iodides of sodium and ammonium are almost as frequently employed, and those of calcium and strontium are in occasional use.
The soluble salts are removed by lixiviation, and the residue is boiled with lime to form the soluble calcium ferrocyanide, which is finally converted into the potassium salt by potassium chloride or carbonate.
The mixture of calcium and lead carbonates is filtered off and roasted at a low red heat in order to regenerate the calcium plumbate.
The calcium salt, when heated with the calcium salts of higher homologues, gives aldehydes.
This mature weathering, resulting in the relatively complete separation of the quartz from the kaolin, and both from the calcium carbonate and other basic materials, implies conditions of rock decay comparable to those of the present time.
In Florida the system contains Y calcium phosphate of commercial value.
Moissan (Comptes rendus, 1893, 116, p. 349; 1894, 119, p. 185) reduces the sesquioxide with carbon, in an electric furnace; the product so obtained (which contains carbon) is then strongly heated with lime, whereby most of the carbon is removed as calcium carbide, and the remainder by heating the purified product in a crucible lined with the double oxide of calcium and chromium.
It is evident that by the use of a spectroheliograph of sufficiently high dispersion, photographs may be taken of vapours in the sun represented by lines narrower than those of calcium and hydrogen.
The spectra of magnesium, calcium, zinc, cadmium and mercury, give the two branch series, and each series is repeated three times with constant difference of frequency.
When we compare together electric discharges the intensity of which is altered by varying, the capacity, we are unable to form an opinion as to whether the effects observed are due to changes in the density of the luminous material or changes of temperature, but the experiments of Sir William and Lady Huggins 1 with the spectrum of calcium are significant in suggesting that it is really the density which is also the determining factor in cases where different concentrations and different spark discharges produce a change in the relative intensities of different lines.
It is found that the lines of the same element do not all show the same shift, thus the calcium line at 4223 is displaced by 0.4 A by ioo atmospheres pressure, while the H and K lines are only displaced through about half that amount.
C. Marignac has prepared it by the action of calcium carbonate on magnesium chloride.
A still more potent absorption is afforded by calcium prepared in situ by heating a mixture of magnesium dust with thoroughly dehydrated quick-lime.
From the manner of its preparation it was clear at an early stage that argon would not combine with magnesium or calcium at a red heat, nor under the influence of the electric discharge with oxygen, hydrogen or nitrogen.
Calcium oxalate is a very common substance, especially in crustaceous lichens; fatty oil in the form of drops or as an infiltration in the membrane is also common; it sometimes occurs in special cells and in extreme cases may represent 90% of the dry substance as in Verrucaria calciseda, Biatora immersa.
The substances used as tests in these reactions are caustic potash and calcium hypochlorite; the former being the substance dissolved in an equal weight of water and the latter a saturated extract of bleaching powder in water.
Slayter went in a coastal motor boat to place a calcium flare in its old position.
Kaolin or China clay is essentially a pure disilicate (Al 2 O 3.2SiO 2.2H 2 O), occurring in large beds almost throughout the world, and containing in its anhydrous state 2 4.4% of the metal, which, however, in common clays is more or less replaced by calcium, magnesium, and the alkalis, the proportion of silica sometimes reaching 70%.
It was also necessary to give the fine charcoal a thin coating of calcium oxide by soaking it in lime-water, for the temperature was so high that unless it was thus protected it was gradually converted into graphite, losing its insulating power and diffusing the current through the lining and walls of the furnace.
As the only light permitted to reach the plate is that of the calcium line, the resulting image will represent the distribution of calcium vapour in the sun's atmosphere.
The calcium clouds or ilocculi thus recorded are invisible to the eye, and are not shown on direct solar photographs taken in the ordinary way.
The calcium flocculi, on account of the brilliant reversals of the H and K lines to which they give rise, and the protection to the plate afforded by the diffuse dark bands in which these bright lines occur, are easily photographed with a spectroheliograph of low dispersion.
A spectroheliograph which gives excellent results with the lines of calcium, hydrogen and iron is shown in the figure.
Photographs of the solar disk, taken with the H or K line, show extensive luminous clouds (flocculi) of calcium vapour, vastly greater in area than the sun-spots.
By setting the camera slit so as to admit to the photographic plate the light of the denser calcium vapour, which lies at low levels, or that of the rarer vapour at high levels, the phenomena of various superposed regions of the atmosphere can be recorded.
These reveal dark hydrogen flocculi, which appear to lie at a level above that of the bright calcium flocculi.
Neither the forms nor the motions of the calcium flocculi revealed the existence of such b
As in other cell-walls, so here the older membranes may be altered by deposits of various substances, such as resin, calcium oxalate, colouring matters; or more profoundly altered throughout, or in definite layers, by lignification, suberization (Trametes, Daedalea), or swelling to a gelatinous mucilage (Tremella, Gymnosporangium), while cutinization of the outer layers is common.
Among those directly visible to the microscope are oil drops, often coloured (Uredineae) crystals of calcium oxalate (Phallus, Russula), proteid crystals (Mucor, Pilobolus, &c.) and resin (Polyporei).
The desulphurizing effect of this transfer of the sulphur from union with iron to union with calcium is due to the fact that, whereas iron sulphide dissolves readily in the molten metallic iron, calcium;sulphide, in the presence of a slag rich in lime, does not, but by preference enters the slag, which may thus absorb even as much as 3% of sulphur.
In the former case there is no later chance to remove sulphur, a minute quantity of which does great harm by leading to the formation of cementite instead of graphite and ferrite, and thus making the cast-iron castings too hard to be cut to exact shape with steel tools; in the latter case the converting or purifying processes, which are essentially oxidizing ones, though they remove the other impurities, carbon, silicon, phosphorus and manganese, are not well adapted to desulphurizing, which needs rather deoxidizing conditions, so as to cause the formation of calcium sulphide, than oxidizing ones.
Further, the more sulphur there is to remove, the greater must be the quantity of slag needed to dissolve it as calcium sulphide.
Consequently, when we deoxidize calcium in the iron blastfurnace, it greedily absorbs the sulphur which has been dissolved in the iron as iron sulphide, and the sulphide of calcium thus formed separates from the iron.
Beside this their chief and easy work of oxidizing carbon, silicon and phosphorus, the conversion processes have the harder task of removing sulphur, chiefly by converting it into calcium sulphide, CaS, or manganous sulphide, MnS, which rise to the top of the molten metal and there enter the overlying slag, from which the sulphur may escape by oxidizing to the gaseous compound, sulphurous acid, S02.
The thorough removal of the sulphur is thus brought about by the deoxidation of the calcium.
It is by forming calcium sulphide that sulphur is removed in the manufacture of pig iron in the iron blast furnace, in the crucible of which, as in the electric furnaces, the conditions are strongly deoxidizing But in the Bessemer and open-hearth processes this means of removing sulphur cannot be used, because in each of them there is always enough oxygen in the atmosphere to re-oxidize any calcium as fast as it is deoxidized.
But if we rely on this means we have difficulty in reducing the sulphur content of the metal to 0.03% and very great difficulty in reducing it to 0.02%, whereas with the calcium sulphide of the electric furnaces we can readily reduce it to less than 0.01%.
As we have seen, the removal of sulphur can be made complete only by deoxidizing calcium, and this cannot be done if much oxygen is present.
We still use the old familiar purifying agents, iron oxide, lime and nascent calcium.
Now, whether a real, though undetected, change occurs is a question to be determined from case to case; it is certain, however, that a substance like aragonite (a mineral form of calcium carbonate) has sensibly persisted in geological periods, though the polymorphous calcite is the more stable form.
There are cement factories in the town, and calcium carbide is an important article .of export.
In his researches on the bleaching compounds of chlorine he was the first to advance the view that bleaching-powder is a double compound of calcium chloride and hypochlorite; and he devoted much time to the problem of economically obtaining soda and potash from seawater, though here his efforts were nullified by the discovery of the much richer sources of supply afforded by the Stassfurt deposits.
It is ordinarily prepared by the fermentation of sugar or starch, brought about by the addition of putrefying cheese, calcium carbonate being added to neutralize the acids formed in the process.
It is easily soluble in water and alcohol, and is thrown out of its aqueous solution by the addition of calcium chloride.
The calcium salt, Ca(C4H702)2 H20, is less soluble in hot water than in cold.
This silt consists largely o alumina (about 48%) and calcium carbonate (18%) with smalle quantities of silica, oxide of iron and carbon.
Primarily but a slight deposit is formed (none until the concentration arrives at specific gravity 1.0509), this deposit consisting for the most part of calcium carbonate and ferric oxide.
This goes on till a density of 1.1315 is attained, when hydrated calcium sulphate begins to deposit, and continues till specific gravity 1.2646 is reached.
The supply of materials containing naturally suitable proportions of calcium carbonate and clay being limited, attempts were made to produce artificial mixtures which would serve a similar end.
Thus when hard limestone is the form of calcium carbonate locally available, it is ground dry and mixed with the correct proportion of clay also dried and ground.
Nothing is added during or after grinding save a small amount (I to 2%) of calcium sulphate in the form either of gypsum or of plaster of Paris, which is sometimes needed to make the cement slower-setting.
Hydrated monoCalcium calcium silicate.
It has a remarkable retarding effect on the hydration of the calcium aluminate, and consequently on the setting of the cement; thus it is that a little gypsum is often added to convert a naturally quick-setting cement into one which sets slowly.
It will be observed that in the hydration of tricalcium silicate, the main constituent of Portland cement, a large portion of the lime appears as calcium hydroxide, i.e.
This limestone consists of calcium carbonate most intimately intermixed with very finely divided silica.
Under this term are comprehended all cements whose setting properties primarily depend on the hydration of calcium sulphate.
In a few minutes the surplus hydrated calcium sulphate is deposited from the solution, and the water is capable again of dissolving 2CaS04 H 2 O, which in turn is fully hydrated and deposited as CaS04.2H20.
The principles which govern the preparation and setting of the other class of calcium sulphate cements, that is, cements of the Keene class, are not fully understood, but there is a fair amount of knowledge on the subject, both empirical and scientific. The essential difference between the setting of Keene's cement and that of plaster of Paris is that the former takes place much more slowly, occupying hours instead of minutes, and the considerable heating and expansion which characterize the setting of plaster of Paris are much less marked.
The quantity of these materials is so small that analyses of Keene's cement show it to be almost pure anhydrous calcium sulphate, and make it difficult to explain what, if any, influence these minute amounts of alum and the like can exert on the setting of the cement.
The setting of Keene's cement takes place by the same sort of process which has been described for the setting of plaster of Paris, the chief differences being that the substance dissolved is anhydrous calcium sulphate and that the operation takes a longer time.
All cements having calcium sulphate as their base are suitable only for indoor work because of the solubility of this substance.
It is made commercially by boiling benzotrichloride (obtained from toluene) with milk of lime, the calcium benzoate so obtained being then decomposed by hydrochloric acid 2C 6 H 5 CC1 3 +4Ca(OH) 2 = (C6H6000)2Ca-1-3CaC12+4H20.
Distillation of its calcium salt gives benzophenone with small quantities of other substances, but if the calcium salt be mixed with calcium formate and the mixture distilled, benzaldehyde is produced.
Manganese is found widely distributed in nature, being generally found to a greater or less extent associated with the carbonates and silicates of iron, calcium and magnesium, and also as the minerals braunite, hausmannite, psilomelane, manganite, manganese spar and hauerite.
Manganese Carbide, Mn 3 C, is prepared by heating manganous oxide with sugar charcoal in an electric furnace, or by fusing manganese chloride and calcium carbide.
The sodium sulphate is afterwards fluxed with calcium carbonate and coal, and a mixture is thus obtained from which sodium carbonate can be extracted by exhausting it with water.
The sulphuric acid present is mostly precipitated as calcium sulphate.
The mud thus formed is settled out, and the clear liquor, which is now quite neutral and contains both manganese and calcium chlorides, is mixed with cream of lime and treated by a strong current of air, produced by a blowing-engine.
The first action of the lime is to convert the manganese chloride into manganous hydrate (Mn(OH) 2) and calcium chloride; then more lime is added which greatly promotes and hastens the oxidizing process.
The object of the latter is to convert the manganous hydroxide by the atmospheric oxygen into manganese dioxide, but this would take place much too slowly if there was not an excess of lime present ready to combine with the manganese dioxide to form a calcium manganite.
Only so much lime is used that an acid manganite is formed corresponding to one molecule of calcium oxide to two of manganous oxide.
There are also other advantages of this process which explain its wide extension, in spite of the fact that only from 30 to 35 parts of the hydrochloric acid employed is converted into chlorine, the remainder ultimately leaving the factory in the shape of a harmless but useless solution of calcium chloride.
Its composition approaches the formula CaOC1 2, and it is regarded as a double salt of calcium chloride and hypochlorite, which by the action of water splits up into a mixture of these salts.
On adding to this solution, after settling out the mud, a quantity of potassium chloride equivalent to the calcium chlorate, the reaction Ca(C10 3) 2 +2KC1=CaC1 2 +2KC10 3 is produced, the ultimate proportions thus being theoretically 2KC10 3 to 6CaCl2, though in reality there is rather more calcium chloride present.
A number of secondary reactions, however, occur, owing partly to the excess of calcium carbonate and coal and partly to the impurities present, so that the solid product of the process, which is called " black-ash," has a somewhat complicated composition.
Its principal constituents are always sodium carbonate and calcium sulphide, which are separated by the action of water, the former being soluble and the latter insoluble.
The lixiviation of the blackash requires great care, as the calcium sulphide is liable to be changed into soluble calcium compounds, which immediately react with sodium carbonate and destroy a corresponding quantity of the latter, rendering the soda weaker and impure.
This change of the calcium sulphide may be brought about either by the oxidizing action of the air or by " hydrolysis," produced by prolonged contact with hot water, the use of which, on the other hand, cannot be avoided in order to extract the sodium carbonate itself.
The calcium carbonate, being insoluble, is easily separated from the caustic liquor by filtration.
The washed-out calcium carbonate, which always contains much calcium hydrate and 2 or 3% of soda in various forms, usually goes back to the black-ash furnaces, but it cannot be always used up in this way, and what remains is thrown upon a heap outside the works.
This " alkali-waste," also called tank-waste or vatwaste, was thrown into heaps where the calcium sulphide was gradually acted upon by the moisture and the oxygen of the air.
The wet alkali-waste as it comes from the lixiviating vats, is transferred into upright iron cylinders in which it is systematically treated with lime-kiln gases until the whole of the calcium sulphide has been converted into calcium carbonate, the carbon dioxide of the lime-kiln gases being entirely exhausted.
All endeavours to obtain either hydrochloric acid or free chlorine in the ammoniasoda process have proved commercial failures, all the chlorine of the sodium chloride being ultimately lost in the shape of worthless calcium chloride.
The solution of calcium chloride is run to waste, the ammonia is re-introduced into the process.
The reversible character of the principal reaction has the consequence that a considerable portion of the sodium chloride (up to 33%) is lost, being contained in the waste calcium chloride solution which issues from the ammonia stills.
The melt is dissolved in water and the dyestuff is liberated from the sodium salt by hydrochloric or sulphuric acid, or is converted into the calcium salt by digestion with hot milk of lime, then filtered and the calcium salt decomposed by acid.
The " Procyon " or calcium stars form a transition between Type I.
When the former is used it is roasted with calcium sulphate or alkali waste to form a matte which is then blown in a Bessemer converter or heated in a reverberatory furnace with a siliceous flux with the object of forming a rich nickel sulphide.
It may be synthetically obtained by distilling oxindole (C 8 H 8 NO) with zinc dust; by heating orthonitrocinnamic acid with potash and iron filings; by the reduction of indigo blue; by the action of sodium ethylate on orthoaminochlorstyrene; by boiling aniline with dichloracetaldehyde; by the dry distillation of ortho-tolyloxamic acid; by heating aniline with dichioracetal; by distilling a mixture of calcium formate and calcium anilidoacetate; and by heating pyruvic acid phenyl hydrazone with anhydrous zinc chloride.
Precipitated calcium carbonate may be used in place of the mercuric oxide, or a hypochlorite may be decomposed by a dilute mineral acid and the resulting solution distilled.
The electroscope is provided with a charging rod C. In a dry atmosphere sulphur or amber is an early perfect insulator, and hence if the air in the interior of the box is kept dry by calcium chloride, the electroscope will hold its charge for a long time.
The waters are tasteless and inodorous, and contain calcium and magnesium bicarbonates, combinations of hydrogen and silicon, and of iodides, bromides and lithium.
It is usually obtained by the distillation of amber, or by the fermentation of calcium malate or ammonium tartrate.
The production of aluminium in Switzerland and Scotland, carborundum and calcium carbide in the United States, and soda by the Castner-Kellner process, began to be conducted on an immense scale.
The substance is best prepared by drying ethyl acetate over calcium chloride and treating it with sodium wire, which is best introduced in one operation; the liquid boils and is then heated on a water bath for some hours, until the sodium all dissolves.
The ore is first treated with dilute sulphuric acid, and then ferrous or calcium chloride added, thus forming copper chlorides.
If calcium chloride be used the precipitated calcium sulphate must be removed by filtration.
Hot air is blown into the filtrate, which contains ferrous or calcium chlorides, to expel the excess of sulphur dioxide, and the liquid can then be used again.
To facilitate the communication of the charge to the needle, the quartz fibre and its attachments are rendered conductive by a thin film of solution of hygroscopic salt such as calcium chloride.
Dextro-tartaric acid occurs in the free state or as the potassium or calcium salt in grape juice and in various unripe fruits.
For the preparation of the acid the crude argol is boiled with hydrochloric acid and afterwards precipitated as calcium tartrate by boiling with milk of lime, the calcium salt being afterwards decomposed by sulphuric acid.
Calcium chloride gives a white precipitate of calcium tartrate in neutral solutions, the precipitate being soluble in cold solutions of caustic potash but re-precipitated on boiling.
It is incompatible with potassium, calcium, mercury and vegetable astringents.
Barium chloride, BaCl 2.2H 2 O, can be obtained by dissolving witherite in dilute hydrochloric acid, and also from heavy spar by ignition in a reverberatory furnace with a mixture of coal, limestone and calcium chloride, the barium chloride being extracted from the fused mass by water, leaving a residue of insoluble calcium sulphide.
Barium carbide, BaC2, is prepared by a method similar to that in use for the preparation of calcium carbide (see Acetylene).
In solution, barium salts may be detected by the immediate precipitate they give on the addition of calcium sulphate (this serves to distinguish barium salts from calcium salts), and by the yellow precipitate of barium chromate formed on the addition of potassium chromate.
Simple alkaline waters containing carbonates, chiefly of sodium along with some magnesium and calcium, are drunk for their utility in gastric and intestinal disorders as well as in rheumatism and gout.
Borax is also prepared from the naturally occurring calcium borate, which is mixed in a finely divided condition with the requisite quantity of soda ash; the mixture is fused, extracted with water and concentrated until the solution commences to crystallize.
More recently, the extensive deposits of borates (chiefly, however, of calcium; see Colemanite) in the Mohave desert on the borders of California and Nevada, and in the Atacama desert in South America, have been the chief commercial sources of boron compounds.
The crystals belong to the monoclinic system, and it is a curious fact that in habit and angles they closely resemble pyroxene (a silicate of calcium, magnesium and iron).
It combines with chlorides of the alkali metals to form double salts, and also with barium, calcium, strontium, and magnesium chlorides.
When calcium sulphate is present, the nascent methane induces the formation of calcium carbonate, sulphuretted hydrogen and water.
If the SH 2 runs short they oxidize the sulphur again to sulphuric acid, which combines with any calcium carbonate present and forms sulphate again.
From the seeds have been obtained starch (about 14%), gum, mucilage, a non-drying oil, phosphoric acid, salts of calcium, saponin, by boiling which with dilute hydrochloric or sulphuric acid aesculic acid is obtained, quercitrin, present also in the fully developed leaves, aescigenin, C12H2n02, and aesculetin, C 9 H 6 O 4, which is procurable also, but in small quantity only, from the bark.
It may be prepared by distilling calcium benzoate; by condensing benzene with benzoyl chloride in the presence of anhydrous aluminium chloride; by the action of mercury diphenyl on benzoyl chloride, or by oxidizing diphenylmethane with chromic acid.
The salts of iron, copper, &c., are then dissolved in water and filtered from the insoluble silica, lead sulphate, and calcium sulphate, which are washed with dilute sulphuric acid.
On the large scale it is prepared by the dry distillation of calcium acetate (CH3C02)2Ca= CaCO3 +CH3COCH3.
The use of sodium hyposulphite as solvent, and sodium sulphide as precipitant, was proposed in 1846 by Hauch and in 1850 by Percy, and put into practice in 1858 by Patera (Patera process); calcium hyposulphite with calcium polysulphide was first used by Kiss in 1860 (Kiss process, now obsolete); sodium hyposulphite with calcium polysulphide was adopted about 1880 by 0.
At some works the silver is precipitated with sodium sulphide, and the liquor, after having been separated from the silver sulphide, is treated with calcium polysulphide, that by the precipitation of calcium sulphate the accumulation of sodium sulphate may be prevented.
The characteristic companion-cells of Angiosperms are represented by phloem-parenchyma cells with albuminous contents; other parenchymatous elements of the bast contain starch or crystals of calcium oxalate.
One of the bestknown anatomical characteristics of the genus is the occurrence of numerous spindle-shaped or branched fibres with enormouslythickened walls studded with crystals of calcium oxalate.
The substitution of potassium chlorate for pyrolusite is recommended when calcium chloride is present in the bittern.
The distillate was further purified by digestion with milk of lime, precipitation with water, and further digestion with calcium bromide and barium oxide, and was finally redistilled.
It occurs in the urine, blood, tissues, and bones of animals, calcium phosphate forming about 58% of bones, which owe their rigidity to its presence.
This method was generally adopted until 1775, when Scheele prepared it from bones, which had been shown by Gahn in 1769 to contain calcium phosphate.
Scheele treated bone ash with nitric acid, precipitated the calcium as sulphate, filtered, evaporated and distilled the residue with charcoal.
Calcium phosphate, mixed with sand and carbon, is fed into an electric furnace, provided with a closely fitting cover with an outlet leading to a condenser.
At the temperature of the furnace the silica (sand) attacks the calcium phosphate, forming silicate, and setting free phosphorus pentoxide, which is attacked by the carbon, forming phosphorus and carbon monoxide.
The calcium silicate remains in the furnace in the form of a liquid slag, which may be run off, so that the action is practically continuous.
By passing the products of the decomposition of calcium phosphide with water over granular calcium chloride, the P 2 H 4 gives a new hydride, P1.2H6 and phosphine, the former being an odourless, canary-yellow, amorphous powder.
Solid Phosphoretted Hydrogen, P 4 H 2, first obtained by Le Verrier (loc. cit.), is formed by the action of phosphorus trichloride on gaseous phosphine (Besson, Comptes rendus, 111, p. 972); by the action of water on phosphorus di-iodide and by the decomposition of calcium phosphide with hot concentrated hydrochloric acid.
The phosphorus used in the British pharma copoeia is obtained from calcium phosphate, and is a waxlike non-metallic substance soluble in oils and luminous in the dark.
The strongest lines are those due to calcium, iron, hydrogen, sodium, nickel, in the order named.
These bands Julius calls dispersion bands, and then, assuming that a species of tubular structure prevails within a large part of the sun (such as the filaments of the corona suggest for that region), he applies the weakening of the light to explain, for instance, the broad dark H and K calcium lines, and the sun-spots, besides many remoter applications.
In calcium, for instance, the g line shows in the laboratory much stronger anomalous dispersion than H and K; but in the solar spectrum H and K are broad out of all comparison to g.
Solution of calcium bicarbonate becomes with gallic acid, on exposure to the air, of a dark blue colour.
They are deep, of fine texture, easily worked and contain abundant plant food in the form of soluble compounds of calcium, sodium and potassium.
It is not found in nature in the free state to any extent, and although enormous quantities of its salts, especially calcium and barium sulphate, are found in many localities, the free acid is never prepared from these salts, as it is more easily obtainable in another way, viz.
As a general class, the sulphates are soluble in water, and exhibit well crystallized forms. Of the most insoluble we may notice the salts of the metals of the alkaline earths, barium, strontium and calcium, barium sulphate being practically insoluble, and calcium sulphate sparingly but quite appreciably soluble.
Cyclo-hexanone, C 6 H 10 0, is obtained by the distillation of calcium pimelate, and by the electrolytic reduction of phenol, using an alternating current.
Some of these cells produced muscles and connective tissue; others absorbed and removed waste products, iron salts, calcium carbonate and the like, and so were ready to be utilized for the deposition of pigment or of skeletal substance.
This operation was necessitated by the fact that carbon dioxide has the power of breaking up the sulphur compounds formed by the lime, so that until all carbon dioxide is absorbed with the formation of calcium carbonate, the withdrawal of sulphuretted hydrogen cannot proceed, whilst since it is calcium sulphide formed by the absorption of sulphuretted hydrogen by the slaked lime that absorbs the vapour of carbon disulphide, purification from the latter can only be accomplished after the necessary calcium sulphide has been formed.
On entering the first purifier, which contains calcium thiocarbonate and other combinations of calcium and sulphur in small quantity, the sulphuretted hydrogen and disulphide vapour have practically no action upon the material, but the carbon dioxide immediately attacks the calcium thiocarbonate, forming calcium carbonate with the production of carbon disulphide vapour, which is carried over with the gas into the second box.
In the second box the formation of calcium thiocarbonate takes place by the action of carbon disulphide upon the calcium sulphide with the liberation of sulphuretted hydrogen, which is carried over to the third purifier.
The contents of the third box, being mostly composed of slaked lime, take up sulphuretted hydrogen forming calcium sulphide, and practically remove the remaining impurities, the outlet gas showing 20 grains of sulphuretted hydrogen and 8 grains of carbon disulphide per Ioo cub.
It will be noticed that in the earlier stages the quantity of sulphur impurities is actually increased between the purifiers - in fact, the greater amount of sulphiding procures the ready removal of the carbon disulphide, - but it is the carbon dioxide in the gas that is the disturbing element, inasmuch as it decomposes the combinations of sulphur and calcium; consequently it is a paramount object in this system to prevent this latter impurity finding its way through the first box of the series.
Calcium ferrite, magnesium ferrite and zinc ferrite, ROFe203(R=Ca, Mg, Zn), are obtained by intensely heating mixtures of the oxides; magnesium ferrite occurs in nature as the mineral magnoferrite, and zinc ferrite as franklinite, both forming black octahedra.
The essential oil is rectified by redistillation with water and alkaline carbonates, and the water which the oil carries over with it is removed by a further distillation over calcium chloride.
Among them, iron, sodium, magnesium, calcium and hydrogen are conspicuous; but it would be rash to assert that any of the seventy forms of matter provisionally enumerated in text-books are wholly absent from his composition.
The pictures were taken, in both cases, with only one quality of light, the violet ray of calcium, the remaining superfluous beams being eliminated by the agency of a double slit.
Iron, calcium and hydrogen may be especially mentioned as three familiar chemical elements which enter largely into the constitution of all the matter of the heavens.
Strontium is sometimes partly replaced by an equivalent amount of calcium.
After the calcium sulphate has settled, the potassium chromate solution is converted into bichromate by the action of sulphuric acid, and the salt is allowed to crystallize.
Similar sodium, ammonium, lithium, magnesium, calcium, barium and zinc salts have been obtained.
To the chloride of calcium is due the smooth and oily feeling of the water, and to the chloride of magnesia its disagreeable taste.
The chemical bodies which have played the most important part as agents of petrifaction are silicic acid and calcium carbonate, though other substances, such as magnesium carbonate, calcium sulphate and ferric oxide have also been concerned, either as the chief constituents of petrifac tions, or mixed with other bodies.
Frankincense burns with a bright white flame, leaving an ash consisting mainly of calcium carbonate, the remainder being calcium phosphate, and the sulphate,.
Calcium salts form insoluble soaps with fats, and combine with albumen in a manner which makes them soothing and astringent rather than irritating.
Calcium and magnesium have actions somewhat similar to that of potassium.
Some of them contain much iron (yellow, blue and red clays); others contain abundant calcium carbonate (calcareous clays and marls).
Berthelot, by digesting with chalk and cheese, obtained from it 12% of its weight of alcohol, along with calcium lactate, but no appreciable quantity of sugar.
Gum arabic may be regarded as a potassium and calcium salt of gummic or arabic acid.
The insoluble part of the gum is a calcium salt of bassorin (C12H20010), which is devoid of taste and smell, forms a gelatinoid mass with water, but by continued boiling is rendered soluble.
The formulation includes vitamin D to promote calcium absorption in the gut.
It is also required for calcium and phosphorus absorption and utilization.
Calcium sources that simply reduce stomach acidity are next to useless.
In some people not being able to make the urine acid called renal tubular acidosis makes calcium phosphate stones more likely.
A CT scan of the abdomen showed both adrenals were enlarged and contained specks of calcium (3C, arrows ).
In this activity, students immobilize the lactase in calcium alginate beads held within a small column, over which the milk is passed.
In 1907 calcium arsenate was introduced for use primarily on cotton crops and in cotton mills.
For them switching to the salt form (sodium ascorbate, calcium ascorbate, magnesium ascorbate, etc.) often permits far higher tolerance.
Nutrobal is a high potency calcium balancer and multivitamin supplement to help bone growth in snakes, lizards and tortoises.
Baryte contains the chemical element barium, which is heavier than the calcium, in gypsum.
It's caused by the presence of calcium bicarbonate in the water.
It is a type of medication called a calcium channel blocker.
Eg captopril, losartan - Calcium channel blockers or alpha blockers, which help widen your blood vessels.
However, the bioavailability of calcium from other plant foods is good, e.g. broccoli (see section 9 ).
Calcium and phosphorus in milk serve to feed nanobacteria, causing calcification and cancer.
Animal protein is high in sulfur which can leach calcium from the bones and form painful kidney stones.
Acid water, which seeps through the limestone layers, dissolves the calcium, which is forming the stalactites.
Long-term use of ascorbic acid at high intake levels may deplete calcium, magnesium and potassium.
Studies have shown that taking 800 to 1,000 mg of supplemental calcium per day can reduce the rate of bone loss in postmenopausal women.
What's more, it also has the most elemental calcium (40% of the total molecule ).
The sunlight when outside in the open also helps the rabbit to absorb dietary calcium.
But coral calcium contains high levels of alkaline minerals which help to promote a more alkaline state.
Bran, an insoluble fiber, reduces the absorption of calcium enough to cause urinary calcium to fall.
Studies in salamanders and mice show that low extracellular calcium increases calcium signaling between neurons in the eye as well as in the nose.