1835.] Pyroxylic Spirit and its Compounds. 379 



9. Formate of Carhydrogen, — This ether was prepared by 

 distilling a mixture of equal weights of sulphate of carby- 

 drogen and formate of soda. The product is distilled over 

 a new portion of formate of soda, and lastly, in a retort from 

 a water-bath. Its formula is C H + C^ H O^ + HO. The 

 density of its vapour is 2*4. 



10. Benzoate of Carhydrogen is formed by the distillation 

 oi 2 parts benzoic acid, 2 sulphuric acid, and 1 part py- 

 roxylic spirit, and precipitating the product by water. By re- 

 distilling the residue of the first operation with new portions 

 of pyroxylic spirit, more benzoate of carhydrogen passes over. 

 The product, after precipitation by water, should be agitated 

 with chloride of calcium, decanted and distilled over dry 

 massicot. It is then to be boiled till the temperature 

 remains fixed about 388°. It is oily, colourless. Sp. gr, 

 1*10. The density of the vapour is 4*717. It consists of 

 C H + Ci5 H6 03 + H O, or 1 atom of each of the 

 ingredients. 



11. Chloro-carhonate of Carhydrogen, When pyroxylic 

 spirit is admitted into a vessel containing chloro-carbonic 

 acid, muriatic acid and chloro-carbonate of carhydrogen are 

 formed. The latter separates in the form of a heavy oil. 

 Its precipitation is secured by the addition of water. It is 

 then decanted, rectified with a great excess of chloride of 

 calcium and massicot. It is a colourless liquid, very vola- 

 tile, with a penetrating odour. It burns with a green flame. 

 It consists of 1 atom of acid and 1 of base. 



12. Sulpho-carbydrogic Acid can be formed by the action 

 of sulphuric acid and pyroxylic spirit, but more readily by 

 dissolving the double sulphate of carhydrogen in water, 

 precipitating the barytes by sulphuric acid, and crystallizing 

 the liquid in a vacuum. The crystals are white needles. 

 It is strongly acid, and forms salts with all the bases. 



Sulpho-carhydrogate of Barytes is prepared by adding 

 gradually 1 part of pyroxylic spirit to 2 parts concentrated 

 sulphuric acid ; much heat is extricated. The liquid, after 

 the cessation of action, is diluted with water, and super- 

 saturated slightly with barytes. 



The liquid is then submitted to the action of carbonic acid, 

 and again filtered. Sulpho-carbydrogate of barytes remains 

 in a pure and neutral state. By careful evaporation it is 

 obtained in the form of beautiful square plates. The salt is 



