1853.] OF THE ROYAL INSTITUTION. 239 
WEEKLY EVENING MEETING, 
Friday, Jan. 28. 
W. R. Grovs, Ese., M.A., F.R.S., Vice-President, 
in the Chair. 
PRoFEssor Wittramson, 
On Gerhardt’s discovery of Anhydrous Organic Acids. 
Tue discovery by M. Gerhardt of a number of anhydrous organic 
acids has thrown so much light on one of the most important 
questions of chemical philosophy, that it constitutes one of the 
most remarkable illustrations of the manner in which the rich 
materials of organic chemistry may be brought to bear on the 
explanation of the phenomena of chemical action and the laws 
of chemical combination. 
It is not unworthy of remark, that the’ bodies prepared by 
Gerhardt had for some years past been supposed to exist ready 
formed in combination with water and other bases, and that the 
chief objection to that supposition was founded on the circum- 
stance of their never having been separated from such combi- 
nation, and presented in an isolated form. In fact Gerhardt has 
supplied the very link in the chain, which was expected to constitute 
evidence for a familiar theory of the constitution of salts. But 
the process by which the result was attained is even more im- 
portant than the result itself, and has led to our drawing from that 
result a conclusion different from that which was generally ex- 
pected. Chemistry aims at discovering the nature of that action 
by which substances of Opposite properties undergo those re- 
markable changes which we call chemical combination ; and it 
naturally follows from this view of its objects, that chemical 
science is more advanced by the discovery of a new process than 
by the discovery of a new substance ; and its theories are more 
immediately affected by the nature of a process of change 
than by any physical fact, such as the existence of a peculiar body 
or class of bodies. Thus it is that the method of isolating the 
anhydrous organic acids, has afforded evidence of anew view of 
the constitution of acids and salts, 
A few words may serve to give an idea of the previous state 
of the question. 
Compounds of oxygen-acids were Supposed to consist of the 
anhydrous acid united with an oxide. Thus hydrated sulphuric 
acid was represented as containing the anhydrous group S O, 
plus an atom of water H,O; and in the saturation of this hydrated 
