Knoxdedge of Conjugate Compomids. 173 



solution in large rhombic tables, which effloresce upon expo- 

 sure to the air. The crystals contain one atom of water ; the 

 effloresced salt is free from water, and is composed of KO + 

 C2 CI3, S2 O5. This decomposition is thus explained — 



2C CI.2 SO^XKO + C2 CI3, S2 O5 



2KO JK CI. 



The hydrous hyposulphate of chloride of carbon, which is 

 obtained by precipitation of the baryta salt with sulphuric 

 acid, crystallizes upon evaporation in small prisms, not per- 

 manent in the air, which may be heated to 150° without de- 

 composition. They are not oxidized by boiling with nitric, 

 nitromuriatic or chromic acids ; nitric and hydrochloric acid 

 may be distilled off from them widiout any change. The salts 

 of hyposulphate of chloride of carbon are soluble in water and 

 in alcohol, and easily crystallizable. They are decomposed 

 by heat into sulphurous acid, chloro-carbonic oxide gas, and 

 the metallic chloride, which last remains free from sulphuric 

 acid, and is colourless. The barytic salt is formed like the 

 alkaline salt, by solution of the sulphurous perchloride of 

 carbon in baryta water; it crystallizes upon evaporation in 

 large four-sided tables; at 100° C. it is composed of BaO + 

 Cg CI3, 83 O5 + aq. The remaining salts are formed by neu- 

 tralising the free acid with a basic carbonate. The ammo- 

 niacal salt crystallizes most readily in fine large prisms. 



Hyposulphate of chloride of formyle, HO+ Cg HClg, SgO^, 

 is the second in this class of coupled acids. It is formed by 

 the substitution of one equivalent of hydrogen for one equiva- 

 lent of chlorine of the hyposulphate of chloride of carbon, 

 when zinc is dissolved by hyposulphate of chloride of carbon, 

 which takes place without the evolution of hydrogen, but with 

 the formation of hydrochloric acid, 



HO + C2 CI3, S2 O5I ZnO + C2 HCI2, S2 O5 

 2Zn JZnCl. 



The potash salt, KO + C^ HClg, 83 O5, is also obtained by 

 boiling caustic potash with sulphite of chloride of carbon, 

 which combines with one atom of water, 

 2C CI SO2I 



KO ^KO + C2,HCl2, S2O5. 

 HO J 

 This salt is easily soluble in water and hot alcohol, difficultly 

 soluble in cold alcohol ; crystallizes from a hot, saturated al- 

 coholic solution in small, shining nacreous leaves ; dried at 

 100° it is anhydrous, and is resolved at 250° C. into hydro- 

 chloric acid, sulphurous acid, carbonic acid and oxide of 

 carbon ; chloride of potassium slightly coloured by charcoal 

 remains behind. The free acid may be obtained by precipi- 



