London Electrical Society. 87 



ment, when the pencil is moved, one of the images remains sta- 

 tionary, the other proceeding alone to coalesce with it. 



From similar experiments, and some physiological considerations, 

 the Doctor infers that one eye may be regarded as a master eye 

 wholly occupied with vision, the other being nearly or wholly pas- 

 sive. This tract will repay perusal. 



The author concludes it with the following problem, which had 

 been treated already by Wollaston, viz. " When a picture looks at 

 you in one part of a room it will look at you in another." The 

 author's solution seems simple and satisfactory. 



XVI. Proceedings of Learned Societies. 



LONDON ELECTRICAL SOCIETY. 



June 15th. — A Letter was read from Martyn Roberts, Esq., Mem. 

 Elec. Soc, describing " Some Experiments which show that Radia- 

 tion, a property of Heat, is not a property of Electricity." The ex- 

 periments were those in which a Bennet's electrometer is exposed to 

 the influence of a charged conductor, and the leaves, which by induc- 

 tion had diverged, collapse the instant the charge is removed from 

 the conductor. This would not be the case if electricity radiated as 

 heat does : it would then pass through the interstices of the air and 

 produce a permanent effect upon the instrument. The author in 

 conclusion said, that " the establishment of facts such as these would 

 throw much light upon the nature of electricity ; and its dissimilarity 

 from, or the analogy it bears to heat, will be one great means of 

 penetrating more deeply into these mysterious agencies." 



A translation was read of a paper entitled " On the Remarks of M. 

 Becquerel relative to the comparative measure of the action of two 

 voltaic pairs, one Copper and Zinc, the other Platinum and Zinc, 

 by M. Jacobi." M. Becquerel had attributed the superior power of 

 the nitric acid battery to the reaction between the nitric acid and 

 the acidulated water. M. Jacobi considers this reaction by no means 

 sufficient to produce the astonishing results obtained from a Grove's 

 battery ; and he alludes to some experiments by which M. Fechner 

 had proved that of the whole power obtained from a battery, whose 

 two exciting liquids were nitric acid and alkali, only ^th part was 

 due to this species of reaction ; and hence M. Jacobi inferred that 

 when acidulated water was substituted for alkali, the amount due to 

 this reaction would be in proportion still less. The author here gave 

 a series of propositions deduced from our present knowledge of vol- 

 taic phenomena ; and concluded with some further experiments in 

 illustration of the actual superiority possessed by the platinum over 

 the copper battery. 



We must refer our readers to the Proceedings of the Society for 

 the other papers which were read : viz. — 



" Descriptive Memoir of an Atmospheric Electrical Apparatus, and 

 its appendages, comprehending an insulated line of wire, extending 



