56 NOTICES OF THE MEETINGS [April 11, 
The Trustees of the British Museum, continued : — 
Nomenclature of Molluscous Animals and Shells. 12mo. 1850. 
List of Homopterous Insects, Part 1. 12mo. 1850. 
List of the British Animals, Part 1, Radiata. Part 2, Sponges. Part 3, Birds. 
Part 4, Crustacea. Part 5, Lepidoptera. 12mo. 1848— 50. 
List of Donations, 1828— 30. 4to. 
Inscriptions in the Cuneiform Character from Assyrian Monuments discovered 
by A. H. Layard, D.C.L. fol. 1851. 
The Asiatic Society of Bengal — Journal, Nos. 215, 216. 8vo. 1850. 
The Chemical Society — Journal, No. 13. 8vo. 1851. 
The Geographical Society of Bombay — Transactions, Vol. I. to VI. and Vol. 
VIII. Part 1. 8vo. 1836—1848. 
The Royal Society — Proceedings, No. 59 and No. 77, parts 1, 2. 8vo. 1851. 
Transactions for 1850, Part 2. 4to. 1851. 
List of Members for 1850. 4to. 
Adam Murray, jun. Esq. M. R. I. — Specimens of British Minerals. 
F. H. Gabriel, Esq. M. R.I.— Fossil Marine Worm from Tale-bank Quarry, 
Wensleydale, Yorkshire. 
Wm. Bollaert, Esqg.— Specimens of Minerals collected in the Texas (vide Trans. 
Geog. Soc. 1843 —49.) 
WEEKLY EVENING MEETING, 
Friday, April 11, 
H. R. H. Prince Ausert, Vice Patron, in the Chair. 
ProressorR Farapay 
On Atmospheric Magnetism. 
On a former evening (January 24, page 1) it was shown that Oxygen 
gas was magnetic, being attracted towards the poles of a magnet ; 
and that like other magnetic bodies, it lost and gained in power as 
its temperature was raised and lowered, and that the change occurred 
within the range of natural temperatures. These properties it car- 
ries into the atmosphere; and the object, this evening, was to show 
how far they might be applied to explain certain of the observed 
variations of the terrestrial magnetic force. 
If a source of magnetic power be considered (as a magnet) it 
presents us with a system having polarity; and if the parts which 
are called the poles be taken as representing the most concentrated 
condition of the polarity, then the contrary polarities, manifest ex- 
ternally in relation to the magnet, are perfectly definite, being exactly 
equal to each other. If the magnet be irregular in the disposition of 
its force, still the same definite character of the sum of the contrary | 
polarities holds good. 
External~to the magnet those concentrations which are named 
poles may be considered as connected by what are called magnetic 
: 
