Intelligence and Miscellaneous Articles. 413 
recognizes a closer connexion between nervous energy and the elec- 
trical power of certain fishes. This theory is strongly confirmed by 
the abundant supply of nerves furnished to the electric organ,—by 
the necessity of integrity in the nerve for producing the electric 
effect,—by the nervous exhaustion consequent on exercising the 
power,—by cessation of the animal functions during extraordinary 
developments of electricity,—and by the muscular effects consequent 
on passing electricity along the nerves of recently killed animals. 
Feb. 21.—Mr. Pollock communicated a series of experiments on 
electric phosphorescence, which led him to infer that this pheenome- 
non is due to induction, that it is the return of the induced particles 
to their normal condition, and that conduction, chemical change and 
colour operate against its production. 
Mr. Walker gave a short description of some drawings he had 
taken of the peculiar appearance presented by a Leyden jar fractured 
during a powerful discharge of the battery belonging to the Poly- 
technic Institution, of which this jar formed a part. 
Mr. Weekes proposes for the future to employ the condenser or 
the multiplier in cases of feeble atmospheric development of electri- 
city. 
LXVIII. Intelligence and Miscellaneous Articles. 
ON CERTAIN METALLIC ACIDS. 
M FREMY, in previous memoirs read to the Academy on ferric 
e and stannic acids, thinks he has proved in his researches 
on the'latter, that a metallic acid assumes electro-negative properties 
only when combined with water, and loses them when rendered an- 
hydrous, and that its capacity of saturation increases with the pro- 
portions of water which it contains; he thinks that the opinion is 
confirmed by the experiments which he has since performed. 
Aluminate of Potash.—It is well known that alumina readily dis- 
solves in potash and soda ; but no definite compound of alumina and 
alkali has hitherto been analysed; the analyses of such a compound 
appears to be important, asit would prove that alumina, in certain 
cases, acts as an acid; it is also well known that alumina is found 
in certain minerals in the state of an aluminate. M. Fremy has 
prepared perfectly crystallized aluminate of potash, and found it to 
be composed of one equivalent of each of its constituents; it is a 
hydrated salt, containing two equivalents of water; thus in neutral 
aluminates the oxygen of the acid is to that of the base as 3: 1. 
Zincate of Potash.—The examination of the compounds of oxide 
of zinc with the alkalies is attended with great difficulties, they are 
usually deliquescent and uncrystallizable, but by treating a solution 
of zincate of potash with a small quantity of alcohol, a salt is obtained 
in long needles, which M. Fremy considers to be a bizincate of 
potash. This salt is immediately decomposed by water into anhy- 
drous oxide of zinc and potash which remains in solution. 
Protoxide of Tin.—The action of the alkalies on this oxide exhi- 
bited some curious peculiarities. According to some chemists a so- 
