6 



REPORT — 1859. 



Potassium-salt „ [ O, Acid sulphate of potassium. 



S H O 3 1 

 Ether f 2 H 5 \ ®' Sulphovinic acid. 



SHO 3 ] 



Amide H J- N, Sulphamic acid. 



H J 

 Represented as a hydrate, it becomes „ O, 



ing series: — 



and enters into the follow- 



Chloride .... S CI O 2 , CI, Chlorosulphuric acid. 

 SCIO 2 



Hydrate 



Potassium-salt 



H 



O, Chlorohydrated sulphuric acid. 



S CI O 2 



tt [• O, Rose's sulphate of chloride of potassium. 



Ether. 



SCIO 2 

 C 2 H 5 



O, Chlorethylated sulphuric acid*. 



But the rational formula which Williamson gave for his compound was 

 neither of these, but a combination of them into one ; namely, 



Cl } 



so 2 ; 



This formula represents a substance at once a hydrate and a chloride, formed 



en 



IT f 



from the double type j, { the two atoms of which are held together by 



H 



O, 



the diatomic radicle S O 2 replacing one atom hydrogen in each. It is obvious 

 that a substance so constituted would react either as a chloride or as a hy- 

 drate, according to the nature of the substances with which it was brought 

 in contact. 



Until the discovery of chlorohydrated sulphuric acid, the idea of poly- 

 atomic radicles was confined to the replacement of two or more atoms of 

 hydrogen in one or more molecules of a single typical substance. The 

 notion of mixed types, of which this substance afforded the earliestf illustra- 

 tion, has been applied by KekuleJ, with remarkable ability, to explain the 

 constitution of a great number of highly complex substances. 



Every substance which can be represented by a formula deriving from a 

 mixed type may also be represented by two or more formulae, each deriving 

 from a simple type, but containing a comparatively complex radicle. In all 

 cases the choice is open between complex types with simple radicles, and 

 simple types with complex radicles §. 



* R. Williamson, Chem. Soc. Quart. Journ. x. 97. 



t Odling, in a paper already quoted (Chem. Soc. Quart. Journ. vii.), represented hyposul- 



\ S U2C ") 



phuric acid as SO 2 deriving from the type ,, 2 q >-, which, however, may be regarded 

 H /" J 



a mere variation of the type H2 n f • 



* Ann. Chem. Pharm. civ. 129. § Comp. Kopp, Jahresber. 1857, 271. 



as 



