rc el 
GLY AFI E LE ee ee ae 
= 
TRANSACTIONS OF TILE SECTIONS. 85 
some method which would afford a discriminating test between the free 
and combined acid. The usual mode, viz. by boiling with carbonate 
of lead, and concluding, if any insoluble sulphate of lead was formed, 
that the acid existed in a free state, was found to be totally fallacious, 
because carbonate of lead decomposes sulphate of soda, contrary to the 
opinion stated in works of medical jurisprudence. Besides, it was 
shown that many of the usually so-called neutral sulphates exhibit in 
reality an acid reaction upon test-paper, as in the instances generally 
of sulphates of potash, iron, soda, barytes, and also in the case of 
alum, &e.; and hence the excess of acid attached to these salts, would 
be apt to act as free acid upon the barytes test. The author, there- 
fore, concludes that the only demonstrative proof which chemistry 
affords, is a quantitative analysis. Thus he found the entire hat to 
contain °356 per cent. of sulphuric acid, probably in the state of alum 
or copperas, and the injured hat, 1°379 per cent., or in other words, 
the hat had received by the injury 1-023 per cent. of free sulphuric 
acid. Here then was afforded clear evidence of the nature of the 
agent employed to effect the injurious object, which could not have 
been conclusive if the matter examined had only amounted to a drop 
or stain. 
The author directed attention to a point connected with sulphuric 
acid in a medico-legal point of view, viz. that the oil of vitriol of 
commerce always contains in this country nitric acid, in addition to 
various other impurities. Barruel has stated that sulphuric acid is 
capable of dissolving platinum. The author has not been able to 
satisfy himself that it dissolves any sensible quantity of gold leaf. 
Barruel attributes the property which he states it to possess, of dis- 
solving platinum, to the sulphuric acid, assuming the function of 
muriatic acid. But the author is not aware of any experiment which 
would authorize this conclusion. He is rather inclined to attribute the 
action, if such an occurrence takes place, to the muriatic acid which is 
present in all the oil of vitriol prepared from sulphur that he has 
examined. It is given out in sensible quantities, when a solid oil, such 
as cocoa-nut oil, is acted on by sulphuric acid. This he ascertained 
several years ago, when examining some Indian oils; and Dr. Kane 
has since corroborated the fact of the existence of muriatic acid in oil 
of vitriol. Although the author has not been able to observe the 
solution of any sensible quantity of gold leaf by the action of oil of 
vitriol, per se, yet if a few drops of muriatic acid be added, the aciion 
becomes very powerful; and by the administration of heat, platinum 
also is dissolved. . These facts, therefore, prove that wherever we have 
oil of vitriol, we may expect also nitric acid. The author added that he 
knew of no certain mode of detecting the presence of nitric acid, save 
by the property which it possessed of dissolving gold and platinum, 
on the addition of muriatic acid. Pure morphia has no action upon 
nitric acid; it is the resin which generally accompanies that alkaloid 
which produces the characteristic yellow colour. But the author found 
that preparations of opium, in which the resin was excluded, afforded 
no colour when nitric acid was added. From an examination 
