1893-94.] 
Dr Walker on Hydrolysis, 
257 
in sodium hydrate solution. The hydrogen was then bubbled 
through a solution of lead acetate. Not the slightest blackening of 
the lead solution was observed after a swift current of hydrogen 
had been passed for four hours at 12°. At 40° blackening was 
noticeable in about an hour, at 60° in less than half an hour, and at 
80° the lead solution began to turn brown almost at once, a distinct 
black precipitate being deposited after a few minutes. 
We may conclude, then, that in fairly dilute solutions of sodium 
sulphide there is practically no free hydrogen sulphide at the 
ordinary temperature, whilst in similar solutions of sodium hydro- 
sulphide there is undoubtedly a partial hydrolysis into sodium 
hydroxide and sulphuretted hydrogen. 
The amount of hydrolysis in the hydrosulphide solution must, 
however, be very small, if we are to judge from its behaviour with 
regard to ethyl acetate. The action of the hydrosulphide on acetic 
ether is in itself of some interest, on account of the parallelism we 
might expect to exist between it and the corresponding hydroxide. 
We find, however, that in this case, as in so many others, the 
analogy between sulphur and oxygen is more formal than real : 
although water and sulphuretted hydrogen are analogous in consti- 
tution, their behaviour is as divergent as possible. 
Whilst water is one of the most chemically active substances we 
know, especially in the sense of endowing other substances with 
reactivity, hydrogen sulphide is not known to be active in this sense 
at all. The fact of the great activity of water may stand in con- 
nection with the circumstance that, according to the electrolytic 
dissociation hypothesis of Arrhenius, it is formed by the union of 
-f- 
the two active ions par excellence, namely, H and OH. To the 
former of these is attributed all acid functions, and to the latter all 
+ 
basic functions. To the ion H we have no analogue, but to the 
ion OH there corresponds the ion SH, which we might not 
unreasonably expect to be endowed with some of the basic character 
of OH. A dilute aqueous solution of a base acts on ethyl acetate 
in the sense of the following equation : — 
•OH + CH 3 -COO-C 2 H 5 = CiVCOO* C2H,0H, 
the corresponding equation for the ion being 
•SH -t- CH 3 -COOC 2 H 5 = CH~COO- -i- C 2 H 5 SH ; 
VOL. XX. 9/7/94 R 
