*? : 
48 Proceedings of the American Philosophical Society. 
In the experiments of De la Rive and Marcet, in which the entering — 
air being made to impinge upon the bulb of a thermometer, was pro- — 
Pp ductive of a fall in the thermometric column, it might be inferred, he ; 
~ éonceived, that the bulb interfered with the access of caloric from the 
space. It was in fact the bulk upon which the air acted previously to its 
distribution in the space where it could have encountered the due propor- 
tion’of caloric. ol 
Prof. Bache, from the committee on magnetic observations, ‘read an 
extract from a letter of Major Sabine, V. P. of the Royal Society of Lon- 
don, stating that the Council of the Society had, on the recommendation 
of the Committee of Physics, expressed their opinion of the importance 
to the plan of combined magnetic observations now in progress, that ob- 
servatories should be established in'the United States, and had instructed 
their President to bring this expression of opinion to the knowledge of 
the government of this country. 
Prof. Bache stated that the resolution just referred to had been adopt 
with a view to aid the efforts of this Society in procuring the erection of 
observatories, as recommended in their memorial to the Secretary of War, © 
which had been referred by that officer to Congress. 
He also read an extract from a subsequent letter from Major Sabine, in 
reference to the progress of the combined magnetic observations, stating 
that the Emperor of Russia had ordered the erection of nine magnetic 
and meteorological observatories in his dominions, to conform, in respect 
to instruments and times of observations, to the system recommended by 
the Royal Society. One of these observatories is to be upon the north- 
west coast of America. 
Prof. Bache stated, that the regular system of bi-hourly magnetic and 
meteorological observations was now established in the observatory at the 
Girard College, and had been in progress since the close of the month of 
May. He intended, at a future day, to present to the Society the names 
of the gentlemen, chiefly members of the American Philosophical Soci- 
ety, by whose contributions a fund had been raised to defray the expense 
of employing the assistants required for these observations. 
On the occasion of the May magnetic term-day for observations at short 
intervals, [29th,] a brilliant aurora had occurred, during which the mag- 
netic instruments were very much disturbed. The details were reserved 
for future presentation, but it was perhaps proper now to state, that an 
auroral arch had been visible here a little after ten o’clock. The same 
phenomenon was observed at Southwick, Mass., by Mr. Holcomb, at 4 
much earlier hour. 
July \7.—Dr. Hare made a communication respecting an extensive 
voltaic apparatus, of the form which he had designated by the name of 
galvanic deflagrator. This apparatus had been constructed for the Lo 
Institute of Boston, under his direction, by request of Prof. Silliman. 
