384 
POPULAR SCIENCE REVIEW. 
of gravity of the engine is lowered ; 2nd. The strain on the moving parts is 
reduced, and these parts may he lightened ; 3rd. The upward pressure of 
the crossheads on the motion-bars is reduced, and the tendency to “ rolling ” 
diminished ; 4th. The strain on the Cylinder fastenings is reduced ; 5th. 
Engines with small driving-wheels pick up their speed sooner than others ; 
6th. The blast, from the greater frequency of the strokes, would act more 
effectually, and hence a smaller boiler would suffice to raise the steam ; 7th. 
A less proportion of the weight would be unsupported by springs, and hence 
the wear and tear of tyres and rails would be reduced. 
Competitive Trial of Rifled Guns. — The following table gives the particulars 
of the guns to be experimented upon by the Ordnance Select Committee : — 
System. 
Characteristic. 
Calibre. 
Weight. 
Length 
of Bore. 
Weight 
of Shot. 
Lancaster 
Commander Scott ... 
French 
J effrey-Britten 
Oval bore 
Long bearings 
Zinc studs 
Expanding projectile 
Inches. 
7 
7 
7 
7 
Cwt. 
149 
149 
149 
149 
Inches. 
126 
126 
126 
126 
lb. 
110 
110 
110 
110 
The mjean ranges attained in the trials already made have been from 1,361 
to 1,604 yards, with 2° elevation, and from 4,543 to 4,779 yards with 10° 
elevation, the charge being 25 lb. of powder. The J effrey-Britten gun has 
been Avithdrawn from trial, the lead on the base of the shot proving too weak 
to withstand the charge. The Scott gun appears thus far to have given the 
best results. Captain Blakely’s 7-inch gun is also under trial. It is stated 
that recently at Shoeburyness 100 rounds were fired from a gun at the rate 
of seven and a half rounds per minute. 
New Prime Mover. — M. Ch. Tellier has proposed ammoniacal gas as a 
substitute in certain cases for steam. Its advantages are stated to be its 
great solubility in water, its easy liquefaction, its capability of supplying 
motive power at the ordinary atmospheric temperature, and of being 
superheated without too great an increase of temperature, the possibility of 
re-collecting it by solution, and the facility of extracting the latent heat from 
the vapour after the latter has been employed, and transmitting it to that 
which is about to be used, by the simple act of dissolving in water. 
Thin Plates of Steel and Iron. — Various firms have lately produced iron 
plates of extreme tenuity by rolling, the thinnest being those obtained by 
Messrs. E. Williams & Co., of West Bromwich. These were 69 square inches 
in area, and weighed only 49 grains, corresponding with about ^-oVo- inch 
in thickness. Messrs. Gillott have also rolled steel plates -r-gVir inch in 
thickness. This is thinner than the thinnest tissue-paper. 
Pneumatic Loom. — Mr. Harrison has introduced a most important improve- 
ment in the power-loom. It has long been known that the picking motion 
which drives the shuttle through the shed is one of the least satisfactory 
.parts of the loom. It is cumbrous, heavy, liable to get out of order, and 
entails vibration in aU parts of the mechanism. Mr. Harrison substitutes 
for the indirect mechanical blow the action of compressed air. At each end 
