50 On the Phenomena produced by Electricity. 
The experiments detailed in these pages were made with the 
apparatus belonging to the Royal and London Institutions ; and 
I was assisted in many of them by Mr. Pepys, Mr. Allen, and 
Mr. Stodart, and in all of them by Mr. Faraday *. 
I am, my dear sir, 
Very sincerely yours, 
Lower Grosvenor-street, Nov. 12, 1820. Humpury Davy. 
of lightning passing through a box of knives, rendered most of them power- 
ful magnets. See Philosophical Transactions, No. 157, p. 520; and No. 
437, p. 97. 
* All the experiments detailed in this paper, except those mentioned 
p. 48, were made in the course of October 1820; the last arose in conse- 
quence of a conversation with Dr. Wollaston, and were made in the beginning 
of November. I find, by the Annales de Chimie et de Physique, for Septem- 
ber, which arrived in London November 24, that M. Arago has anticipated 
me in the discovery of the attractive and magnetizing powers of the wires 
in the Voltaic circuit ; but the phenomena presented by the action cf com- 
mon electricity (which I believe as yet have been observed by no other per- 
son), induce me still to submit my paper to the Council of the Royal Society. 
Before any notice arrived of the researches of the French philosophers, I 
had tried, with Messrs. Allen and Pepys, an experiment, which M. Arago 
likewise thought of,—whether the arc of flame of the Voltaic battery would 
be affected by the magnet ; but from the imperfection of our apparatus, the 
results were not decisive, I hope soon to be able to repeat it under new 
circumstances. 
I have made various experiments, with the hope of affecting electrified 
wires by the magnetism of the earth, and of producing chemical changes 
by magnetism; but without any successful results. 
Since I have perused M. Ampere’s elaborate treatise on the electro-mag- 
netic phenomena, I have passed the electrical shock along a spiral wire 
twisted round a glass tube containing a bar of steel, and I found that the 
bar was rendered powerfully magnetic by the process. 
Without meaning to offer any decided opinion on that gentleman's inge- 
nions views, I shall beg permission to mention two circumstances, which 
seem to me unfavourable to the idea of the identity of electricity and mag- 
netism; Ist, the great distance to which magnetism is communicated by 
common eleetricity (I found that a steel bar was made magnetic at fourteen 
inches distance from a wire transmitting an electric shock from about se- 
venty feet of charged surface); and, 2d, that the effect of magnetizing at a 
distance by electricity takes place with the same readiness through air and 
water, glass, mica, or metals ; i.e. through conductors and non-conductors. 
IX. True apparent Right Ascension of Dr. MASKELYNE’s 
36 Stars for every Day in the Year 1821. By the Rev. 
J. Groosy. 
{Continued from vol. lvii. p. 408.] 
Argu- 
