135 
Arr. XIII. PROGRESS OF FOREIGN SCIENCE. 
In Volume XIII. p. 144, we briefly animadverted on some re- 
searches of Professor Gmelin, of Tubingen, published in Dr. 
Brewster’s Journal, about two years ago, where the terms refute, 
and refutation were applied with more freedom, than propriety or 
decorum, to Sir. H. Davy’s fundamental experiments relative to 
the connexion of chemical affinity with electrical attractions, con- 
tained in his Bakerian Lecture of 1806. M. Becquerel read to the 
Academy of Sciences on the 7th June, 1823, an interesting paper 
on the electrical effects which are developed during different che 
mical actions, which perfectly accord with, and seem fully to con- 
firm, the conclusions of the English philosopher. After a candid 
retrospect of preceding inquiries on the subject, M. Becquerel thus 
states Sir H. Davy’s theory: “ Supposing two bodies, whose mo= 
lecules are in different states of electricity, and that these states 
are sufficiently exalted to give them an attractive force, superior to 
the power of aggregation, a combination will be formed. This is 
the key of the electro-chemical theory.” ‘ Although Sir H. 
Davy has advanced the opinion, that the substances which com+ 
bine are those which manifest on mutual contact, opposite elec- 
trical states, yet we perceive from his own experiments that it is by 
induction he extended this property to all the bodies which exert 
chemical actions on one another; for instance, he was not able to 
verify it on alkaline and acid substances, unless they were per 
fectly dry. In other cases, the results were null. He adduces, 
among others, pure potash, and sulphuric acid, which afford no 
appearance of electricity at the moment of their combination. In 
fact, this celebrated chemist could not recognise electricity in the 
contact of two substances which are just combining ; for, adopting 
the electro-chemical theory, as soon as the combination takes 
place, the two electricities that were developed, recombine, and 
probably form, by their union, caloric: whence, in making use of 
a condenser to collect one of the electricities which is disengaged, 
traces of this fluid ought to be found with difficulty, since the con- 
denser requires a certain time to charge itself, during which the 
two electricities may re-combine. But if a galvanometrical mul- 
tiplier be employed, such as that of M. Schweigger, which renders 
the electricities sensible at the very instant of their disengagement, 
and consequently at the instant when the combination takes place, 
currents will be obtained of greater or less force, according to the 
degree of conductibility of the substances put in action, and that 
of their reciprocal affinities; I say according to the degree of con- 
ductibility, because when one of these substances conducts the 
