CHEMISTRY. 



83 



Arienitrt. 



along with charcoal powder, they are decomposed, 

 and arsenic sublimes. 



Sp. 1. Arseniate of Potash. This salt does not 

 crystallize. It deliquesces, and changes vegetable 

 blues to green. The superarseniate of potash is a 

 transparent white salt, which crystallizes in four-sided 

 prisms, terminated by four-sided pyramids. It is so- 

 luble in water, and gives a red colour to vegetable 

 blues. 



Sp. 2. Arseniale of Soda. This gait crystallizes in 

 lix-sided prisms. The smperarseniate does not cry- 

 stallize. 



Sp. 3. Arseniate of Ammonia. This salt crystal- 

 lizes in rhomboidal prisms. With an excess of acid 

 it crystallizes in needles. 



Sp. 4. Arseniate of Magnesia. This salt does 

 ot crystallize, but may be obtained in a solid gummy 

 mass. 



Sp. 5. Arseniate of Lime. This salt crystallizes, 

 and is soluble in water. 



Sp. 6. Arseniate of Barytet. This salt is insolu- 

 ble in water, and cannot be crystallized. 



Sp. 7. Arseniate of Alumina. This salt is a white 

 powder insoluble in water. 



Sp. 8. Arseniate of Ytiria. This salt is likewise a 

 white powder, which does not crystallize. 



GENUS XIII. Arsenites. 



The term arsenite has been applied to the combi- 

 nations of white oxide of arsenic with the salifi-ible 

 bases. The alkaline arsenites are yellow-coloured 

 masses with a nauseous odour, not crystallizable, for- 

 merly called livers nf arsenic. The earthy arsenitei 

 are white powders nearly insoluble in water. 



GENUS XIV. Molyldatet. 



If into a solution of a molyhdate a cylinder of tin 

 with some muriatic acid be put, the liquid gradually 

 assumes a deep blue colour. 



Sp. 1. Molifbdate of Potash. This salt crystalli- 

 zes in sirall rhombouial plates. It is bright, and hag 

 a metallic taste. It is soluble in hot water. 



Sp. 2. M'ltybdate of Soda. This salt crystallizes, 

 and is very so'uhle in water. 



Sp. 3. Malt/Mate of Ammonia. Thit salt is solu- 

 ble in water, and does not crystallize. 



Sp. 4. Molybdale of Mtignetia. This salt also is 

 soluble in water, and dor- not crystallize. 



Sp. 5. Moltfbdate of Lime. This is a white inso- 

 luble powder. 



GENUS XV. Tungslatet. 



Tungttattt. These salts are combinations of yellow oxide of 

 tungsten with the salifialile bases. 



Sp. 1. Tungstate of Potash. This salt is soluble 

 in water, deliquesces, and does not crystallize. Its 

 taste is metallic and caustic. 



Sp. 2. Tungstate of Sodft. This salt crystallizes 

 in elongated hexahedral plates. Taste acrid and 

 caustic. Soluble in four parts of cold and two parts 

 of boiling water. 



Sp. 3. Tungttateof Ammonia, This salt crystal- 



Elements 

 of 



Chemistry- 



Molyb- 

 dates. 



lizes in needles or small plates. Its taste is metallic. 

 It is soluble in water, and does not deliquesce. 



Sp. 4. Tungstate of Magnesia. This salt crystal- 

 lizes in small brilliant scales. It is soluble in water, * "~ Y ~ 

 and not altered by exposure to the air. 



Sp. 5. Tungstate of Lime, This salt is found native. 

 It is usually crystallized. The crystals are octahe- 

 drons. Colour yellowish grey, semi-transparent. It 

 is insoluble in water, and not altered by exposure to 

 the air. 



Sp. 6 and 7. The tungstates of barytes and of alu- 

 mina, are white insoluble powders scarcely examined. 



GENUS XVI. Chromates. 



This genus of salts has been but imperfectly exa- Chromates. 

 mined. The salts have usually a yellow colour. The 

 alkaline chromates and chromate of lime are soluble 

 in water, and crystallize. Chromate of barytes ap- 

 pears to be insoluble. 



GENUS XVII. Columbatet. 



This genus of salts has been very imperfectly exa- Colum. 

 mined. We know only the columbate of potash, bate*, 

 which crystallizes in scales. Its taste ia acrid and 

 disagreeable. 



ORDER II. 



Combustible Salts. 

 GENUS I. Acetates. 



THE acetates are all soluble in water. Heat de- combut- 

 composes them, driving off and destroying the acid, tiblc Salts. 

 When mixed with sulphuric acid and distilled, acetic Acetates, 

 acid comes over, easily distinguished by its smell. 



Sp. 1. Acetate of Potash. This salt is usually 

 obtained in plates, but it crystallizes regularly in 

 prisms. It lias a sharp warm taste. It deliquesces 

 in moist air, but in dry air undergoes but little alter- 

 ation. It is soluble also in alcohol. When heated 

 it melts, and in a high temperature is decomposed. 



Sp. 2. Acetate of Soila. This salt crystallizes in 

 striated prism-, nut unlike those of sulphate of soda. 

 It has a sharp taste, inclining to bitter. It dissolves 

 in rather less than three times its weight of cold wa- 

 ter. It is not affected by exposure to the air. When 

 heated it lot>es its water of crystallization, and is de- 

 composed. 



Sp. 3. Acetate of Ammonia. This salt, called for- 

 merly spirit of Mtndererus, cannot easily be crystal- 

 lized by evaporation, but it may be obtained in needles 

 by slow sublimation. Its taste is similar to that of a 

 mixture of sugar and nitre. It is very deliquescent. 

 It melts at 170, and sublimes at about 250. 



Sp. 4. Acetate of Magnesia. This salt does not 

 crystallize. It has a sweetish taste. It is very solu- 

 ble both in water and alcohol. It deliquesces in the 

 air. 



Sp. 5. Acetate of Lime. This salt crystallizes in 

 needles, and has a glonsy appearance like satin. Iti 



