lr fe 
i. 
. ~ 
by steam or water. A great deal of it is then washed, and, 
by means of sieves, the lighter particles of the stone are 
separated from the ore. After these processes (besides 
others which the peculiar nature of some ores may render 
necessary) the ore is considered to be in a fit state for 
smelting ; which for many years has been usually effected 
at Swansea, from its advantageous situation, and the cheap- 
-ness of fuel—the mining captain, or superintendent, on 
shipping it for the purpose, being careful to take from the 
bulk, from time to time during the shipment, small quan- 
tities by way of sample, which he afterwards mixes toge- 
ther and puts in two small bags, one of which he sends 
with the vessel to the consignee, and the other retains in 
his own possession, as a guarantee against the cargo being 
either damaged or undervalued. The ore on arriving at 
Swansea is usually exposed in a yard with other ores; and 
a ticket or label is attached to it, showing whence it comes. 
Sales by auction of the various consignments take place 
periodically, at one of which it shares its fate with others ; 
and, on being put up, is declared the property of the 
highest bidder, who is invariably a smelter. 
510 Learned Socteties. 
PE ARNE D SOCIETY = 
THE ROYAL SOCIETY. 
On Saturday, the 13th ult., General Sabine, the President 
- of the Royal Society, held his second reception. The 
gathering was a most brilliant one, and the scientific attrac- 
tions were very numerous. The collection was of a more 
general character than at the previous sozrée. Art was 
largely represented. Spectral analysis was exemplified by 
the apparatus of Dr. Gladstone and Mr. Sorby. Iron ship 
building, by models of great beauty. Photography, by 
works from the cameras of Mr. Marion and the Messrs. 
Maull, while the magneto-electrical machine of Mr. Ladd 
showed a marked advance in the practical application of 
the principle which renders it possible to convert mechanical 
force into electricity. 
IMPORTANT FACTS CONCERNING GUN COTTON.— 
We have been favoured with the following corrected abstract 
