CO 
’ ad . 
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British Association for the Advancement of Science. 119 
Dr. Clark read a paper on the limits within which the equivalent 
weights of elementary bodies have been ascertained. As the re- 
sult of various researches, Dr. C. stated the following equivalents : 
Lead, Least, 1292.65 Greatest, 1293.89 Mean, 1293.27 
A 
Sulphur, “ 199.45 “200.77 « 200.09 
Azote, «175.42 “177.20 “176.31 
Carbon, 75.28 «75.92 “ 75.60 
Dr. R. D. Thomson read an essay on the proofs of the eristence — 
of free muriatic acid in the stomach during digestion. He offered 
Various reasons for doubting the certainty of the conclusion that 
muriatic acid thus exists, but that as the experiments which he 
had instituted in regard to the subject were not completed, he 
brought them forward at this time chiefly to show the necessity 
of further investigation. 
Mr. Benson presented a paper on the theory of the formation of 
White Lead. He stated that white lead made from litharge, 
(protoxide of lead,) was rejected by painters. It is found that 
prepared in this way it is crystalline and partly transparent, 
whereas the ordinary white lead is amorphous and opake. It is 
found that in order to obtain the amorphous carbonate (or white 
lead) from litharge the latter must be supplied with a very minute 
-. portion of acetic acid. 
Prof. Schénbein of Basle proposed a new theory of the galvani- 
zation of metals. 'The discovery of the chemical power of the 
Voltaic pile, made at the beginning of the present century by 
British philosophers, drew the attention of the scientific world to 
the relations between chemical and electrical phenomena. In- 
deed, only a few years after this important fact had been ascer- 
tained, Davy and Berzelius did not hesitate to assert the theory, 
since generally adopted,—viz. that chemical and electrical forces 
are essentially the same. Prof. S. enumerates the results of sev- 
eral recent experiments which he considers as invalidating this 
theory. From these results he infers—1st. That neither common 
hor voltaic electricity is capable of changing the chemical bear- 
ings of any body, and that the principles of the electro-chemical 
theory, as laid down by Davy and Berzelius, are fallacious. 2d. 
e change which certain metallic bodies, when placed under 
the influence of a current, seem to undergo with regard to their 
chemical sia is due to the production of some substance or 
