412 Progress in Science. [July, 
The magnetic sand, which exists in immense quantities on all sides of 
Mount Etna, has a sp. gr. of 2°813, and is scarcely aGed on by acids. The 
results of its analysis by J. B. Hannay gave—Silica, 52°71; magnetic oxide of 
iron, 19°44; alumina, 19:09; lime, 6°61; and magnesia, 1°85. 
THE PROGRESS IN SCIENCE AT THE INTERNATIONAL 
EXHIBITION OF 1872. 
STEERING the South Gallery we are in the department apportioned to 
recent scientific inventions and new discoveries. This year the depart- 
ment presents no striking feature, so that we must proceed to notice the 
exhibits as they occur tous. At the entrance of the South Gallery stands the 
Electric Motor Clock of Messrs. Cooke and Son, of York ; this clock, a€tuated 
by a not very powerful battery, controls and drives the many clocks required 
in the Exhibition buildings. The instrument has now stood a very severe 
test, this being the second year of its working successfully. The construction 
is exceedingly simple. There are several excellent electric clocks exhibited by 
Messrs. Moseley and Co., in the French annexé, of which we are sorry no 
description has been given. Continuing, however. our walk through the South 
Gallery, we pass a bowser, for tightening and holding ropes, exhibited by 
A. Paget and Co., several hoists and pulley-blocks, by Tangye Brothers and 
Holman, and by Head, Wrightson, and Co., and arrive before a model of a house, 
constructed entirely of waterproof paper, and over which a plentiful rain of 
water is continually flowing. The paper is rendered waterproof by the cupro- 
ammonium process, now the property of the Waterproof Paper and Corrugated 
Fibre Company, and can be seen in the roll, single or double. There are also 
combinations of cotton or linen fabrics with waterproof paper, in slabs, flat or 
corrugated, of various thicknesses, for roofing or building purposes, waterproof 
tubing, panels, &c. Cupro-ammonium is stated to be prepared by the immer- 
sion of copper scraps in concentrated liquid ammonia. The fluid becomes 
deep blue in colour, and possesses remarkable solvent and agglutinising pro- 
perties with regard to paper, linen, silk, and bone. Fibrous material treated 
with this fluid is rendered waterpoof. It is stated that oxide of copper preci- 
pitated and re-dissolved by ammonia does not possess the solvent power of the 
solution obtained by the immersion of copper-turnings in ammonia. Any 
paper sent to the company is made waterproof and corrugated at an expendi- 
ture of 40 percent on the original cost. Near to this exhibit are two non- 
conducting cements for covering boilers and steam-pipes by Messrs. Fox, 
Head, and Co., and by Messrs. Leroy and Co. Mr. Barlow, F.R.S., exhibits 
a very clever instrument for calculating the cubical contents of earthwork. 
Messrs. T. A. Skelton show a Catoptric Street Lamp now in use on Waterloo 
Bridge, devised to prevent the waste of light from the higher parts of the 
lamp. The invention consists in arranging strips of silvered glass in such a 
way that the maximum amount of light is thrown upon the pathway. Messrs. 
Lynch and Co. exhibit a knobbed blue-glass poison-bottle to prevent the use of 
poison by mistake in the dark. Captain E. Sawyer contributes three drawings ofa 
pivot-revolving gun-carriage on rails. This year there are exhibited many 
very useful little inventions, all of which it is impossible that we can 
enumerate. Among the most prominent is a contrivance for the prevention of 
guttering in candles, the contribution of the Rev. J. Langton Clarke, a small 
glass socket fitting on the candle. This socket is studded with small points 
of coloured glass, forming a very pretty as well as useful ornament. Another 
of these minor inventions, and one that will be appreciated by artists, is a 
reservoir palette for flat tints, preventing evaporation, by Messrs. Ackermann. 
Returning to what must really be the true object of an exhibition of this 
nature, the development of manufactures, we have a model of a patent 
Puddling Furnace, by Mr. Danks; a model of a kiln for burning bricks, by Mr. 
Batchelar; and a cutting and crushing sugar machine from Belgium, contri- 
buted by Léon Goffin. Captain W.H. Noble, R.A., contributes some speci- 
