376 PRELIMINARY OBSERVATIONS. 



posulphuric acid it has hydrate of sulphuric acid attached to it. 



Sulphurous acid, -2; hydrated hyposulphuric acid, - 3_ 

 o D. a. H 



The neutral substance, benzile, C 14 H 5 O 2 , or C 28 H 10 O 4 , be- 

 comes benzilate of potash, by fixing the elements of hydrate of 



potash; thus benzile, ^ 4 ; benzilate of potash, ^^^^ 



C 28 L, 28 . tt.i^. 



When the potash is withdrawn from the latter by a stronger 



acid, hydrated benzilic acid is formed, ^(A-^-Q When 



O 28 . H.H 



neutralised with bases, this hydrate loses an atom of water and 

 acquires an atom of metallic oxide in its place. 



Chlorisatin^ a neutral substance, when dissolved in caustic 

 potash is converted into chlorisatinate of potash, in a similar 



TT (~1](~) "M" 



manner : Chlorisatin, ^ 3_ ; chlorisatinate of potash, 



^32 



H 4 C1O 3 N.O.O Deconiposed by a strong ac id, the latter salt 

 L 16 U.K. 



,,,.,.. ., H 4 C1O 3 N.O.O 

 gives hydrate of chlonsatimc acid, 4 



t/ l6 . H.H. 



Concentrated acids decompose this hydrate, assuming its 

 water, and reproduce the neutral chlorisatin. It is clear that 

 the anhydrous acids generally, such as SO 3 , PO 5 , &c., belong 

 to the class of sulphobenzide and chlorisatin, and owe their 

 power of combining with bases to the association with them of 

 an atom of water. 



Hydrate of sulphuric acid, 3 ' ; hydrates of phospho- 



*- -S ' 



We have other series of compounds of which the members 

 only differ from each other, in containing different proportions 

 of water or its elements attached to a common basis, as starch, 

 gum and starch sugar ; gum being starch plus 1 atom of water ; 

 and starch sugar, starch plus 2 atoms of water. It is at present 

 impossible, however, to assign a probable molecular formula to 

 the basis of the starch and many other series of compounds, from 

 our ignorance of the function of the hydrogen in their constitu- 

 tion, where the hydrogen has not been replaced by another 

 element more decidedly chlorous or basic in its character. 



