.Testing for, and Estimation of, Sulphur.¡ª
A variety of methods have been proposed for detecting and estimating the amount of adidas copa mundial this element in organic substances. The subject is invested with a high degree of interest, in consequence of the sharp discussion which has lately taken place between Professors Liebigand Mulder,respecting the existence or non-existence of this principle in the so-called proteineof adidas f50 adizero trx fg the latter chemist. The following are the principal methods which have been published:¡ª
1. Rilling's Process*.¡ªThe finely pulverized substance is fused in a spacious silver dish, with about twelve times its weight of caustic potash, perfectly free from sulphuric acid; it is then mixed with pure nitre, in weight equal to about half the potash employed, and heated till the fused mass appears perfectly white. The whole is then supersaturated with hydrochloric acid, and a salt of baryta added : the formation of a white precipitate indicates sulphur. It consists of sulphate of baryta, and is collected, washed, dried, and ignited. Its weight furnishes the datum for calculating the amount of sulphur originally present in the substance.
2. Kemp's Process f.¡ªFine quartz
sand, which has been carefully tested for sulphuric acid, is mixed with chlorate of potash, in the proportion of adidas predator x fg twothirds of the former to one-third of the latter. The substance to be examined is intimately mixed with the above, introduced into a large platinum crucible, and exposed to a high temperature over a spirit lamp. The process is completed in a few seconds. The contents of the crucible are treated with boiling distilled water, the insoluble portion separated by filtration, and washed till no traces of sulphuric acid remain : the sulphates and phosphates, if any exist, may by this plan be estimated simultaneously by means of a salt of baryta. The object of the sand is to prevent the too rapid oxidation of the organic body, and the risk of a portion being thrown out of the crucible.
3. Weideniusch's Process*.¡ªThe substance is mixed with an excess of nitrate of baryta, and stirred in a beaker glass, with the most concentrated fuming nitric acid to a thin paste ; the beaker is covered and exposed to the temperature of the sand bath, replacing the evaporated nitric acid until the organic substance is entirely destroyed, which is perceptible from the circumstance that, on evaporating the nitric acid still present, the mass begins to thicken, but no longer ascends in large bubbles in the glass, and dries quietly without frothing. The decomposed mass is now carefully washed into a adidas football boots platinum dish, dried at 212¡ã, and then heated gradually until the saline mass is perfectly liquid. If the organic substance had not been completely destroyed by the nitric acid, it frequently happens that the mass takes fire, and a portion is projected from the slight deflagration. This must be avoided, as it occasions a loss of substance ; but, even though this were not the case, a smaller quantity of sulphate of baryta would probably be obtained, since it appears that the sulphur still contained in organic combination is not oxidized so readily by the deflagration of the mass as by the slow action of the nitric acid. The fused mass is carefully separated from the platinum dish, and treated in a beaker glass with dilute acetic acid, and heat applied as long as any evolution of gas is perceptible. The carbonate of baryta is decomposed, and the residue (if any) consists of pure sulphate, which is collected on a filter, washed, dried, heated to redness, again digested with acetic acid after ignition, and again heated to redness. After the second ignition it is perfectly pure, and the amount of sulphur may bo calculated from it.

Separation ofFluoridesfrom Phosphates.¡ª
The process of Berzeliusas modified by Regnault,which we have described above, for separating fluorides from silicates, may also be employed when phosphates also are present. In this case the solution filtered from the silicic acid will contain phosphate of soda in addition to fluoride of sodium and carbonate of soda. It is analyzed as follows : it is rendered ammoniacal, and mixed in a glass flask which can be closed air-tight with a solution of chloride of calcium; the precipitate which is produced consists of fluoride of calcium and phosphate of lime. It is washed with the proper precautions, dried, ignited, and weighed ; it is then treated in a platinum crucible with concentrated sulphuric acid, and heated until the whole of the hydrofluoric acid is expelled. The residue is treated with alcohol in which sulphate of lime is insoluble, and the phosphoric acid dissolved in the alcohol is precipitated and estimated as pyrophosphate of magnesia. The amount of fluorine originally present in the mixed precipitate of fluoride of calcium and phosphate of soda is learnt by the loss of weight sustained by the action of the sulphuric acid.
The quantitative determination of this acid is effected by precipitating its chlorine in the form of chloride of silver; for the composition of this salt, and for the precautions to be observed in its precipitation, the student is referred to p. 137-8. If hydrochloric acid alone is present in aqueous solution, it may be estimated in adidas adipure iii the form of sal ammoniac by adding ammonia in excess, evaporating the solution to dryness, and performing the exsiccation of the residue in the water bath.
Soluble chlorides are analyzed by first precipitating the chlorine by nitrate of silver, and then, after removing the excess of the silver salt from the filtrate by hydrochloric acid, estimating the amount of base or bases by the ordinary processes.
The analysis of the compounds of chlorine with tinand antimonyis performed in a somewhat different manner. If a solution of nitrate of silver were added to a solution of perchloride of tin, there would be precipitated, besides chloride of silver, a compound of peroxide of tin with oxide of silver, which adidas f50 adizero fg would vitiate the result. It is necessary, therefore, to remove the base from the solution before attempting to precipitate the electro-negative element ; this is done by passing through the solution, contained in a flask which can be corked, a stream of adidas f50 prime sulphuretted hydrogeu, and, when it is saturated, allowing it to repose for a considerable time; the sulphuret of tin is filtered off as soon as it is completely subsided, and the excess of sulphuretted hydrogen removed from the filtrate by mixing it with a solution of sulphate of copper ;¡ªthis is indispensable ; otherwise, on the addition of nitrate of silver, a precipitate both of chloride and of sulphuret of silver would take
place. The excess of sulphuretted hydrogen being removed, the solution is precipitated tiy nitrate of silver in the usual manner. In the case of chloride of adidas f50 adizero antimony, it is unnecessary to remove the base previous to determining the chlorine; but the precaution must be taken of mixing the solution with a sufficient quantity of tartaric acid to prevent the formation and precipitation of a basic salt.
Such chlorides as are insoluble, or only sparingly soluble, in water, but soluble in nitric acid, are dissolved in the latter menstruum, the solution diluted with water, anil precipitated by nitrate of silver in the usual manner.