BY DR. HARE. 
207 
cannot be held that this faculty is the result of its previous 
conversion into an oxycarbionide of hydrogen. 
65. Chromic acid is admitted not to require water for 
isolation, and cannot, therefore, be considered as oxyehro- 
mionide of hydrogen. Yet the oil of bitter almonds, which 
consists of a compound radical, benzule, and an atom of 
hydrogen, and which is therefore constituted precisely as 
the salt radical doctrine requires for endowment with the 
attributes of an " hydracid," is utterly destitute of that acid 
reaction which hydrogen is represented as peculiarly com- 
petent to impart. It follows that we have, on the one hand, 
in chromic acid, a compound endowed with the attributes of 
acidity, without being a hydruret of any compound radi- 
cal; and, on the other, in oil of bitter almonds, a hydruret 
of a compound radical, without any of the attributes of 
acidity. 
66. The last argument in favor of the existence of salt 
radicals, which I have to answer, is that founded on certain 
results of the electrolysis of saline solutions.* 
67. On subjecting a solution of sulphate of soda to elec- 
trolysis, so as to be exposed to the current employed, simul- 
taneously with some water in a voltameter, Daniell alleges 
that, for each equivalent of the gaseous elements of water 
evolved in the voltameter, there was evolved at the cathode 
* It is well known that Faraday employed a very simple instrument 
to ascertain the quantity of the gaseous elements of water yielded in a 
given time, by a liquid subjected to the voltaic current. It consisted of 
a graduated tube, through the cavity of which the current was conveyed 
by wires, so terminating within it, as to have an interval between them 
through which the current, being conveyed by the electrolytic process, 
effected the decomposition of the intervening liquid, the resulting gas 
being caught and measured by the tube. This instrument has been 
called a volta electrometer, or voltameter. 
Faraday found that when various substances were electrolysed, a 
voltameter being at the same time in the circuit, that for every equiva- 
lent of water decomposed within the tube, neither more nor less than 
an equivalent of the other body could be decomposed. 
