572 
POPULAR SCIENCE REVIEW. 
nation has recently been made, the boilers having been in use for a year 
and a half. The steel boiler was found in excellent condition. It appeared 
that it evaporated 1T66 cubic feet per hour, against 9*37 by the common 
boiler, with about the same expenditure of fuel. Steel drills for shaft 
sinking are taking the place of the old iron drills steeled. Stamp heads 
for crushing ore have hitherto been made of cast iron, the fragments of 
which mixed with and contaminated the ore, often causing great trouble. 
A trial is now being made of steel stamp heads, doubtless with considerable 
advantage. 
Aluminium. — Messrs. Mappin Brothers are exhibiting various articles in 
aluminium and its alloys. The main portions of the articles are usually 
formed of the aluminium-bronze, and a good effect is produced by relieving 
this with ornaments of “ oxidized ” aluminium whitened by the addition 
of a small amount of nickel. C. Fissier, director of the aluminium works 
at Rouen, shows that one per cent, of aluminium in copper makes the 
latter more fusible, giving it the property of filling the mould at casting. 
The copper gains in hardness and tenacity without losing its malleability. 
In transverse strength this alloy was found to be more than twice as rigid 
as either brass or copper. An alloy of one part of aluminium to a 
bronze of 96 copper and 4 tin has a fine colour and is very homo- 
geneous. It does not oxidize in casting, and its transverse strength is two 
and a half times that of the original bronze, and after hammering four 
times the latter. At a recent meeting at the Royal Institution, Messrs. 
Johnson & Mattliey exhibited an alloy of aluminium and nickel, containing 
one and a half per cent, of the latter, which has been tried by hydraulic 
pressure to 476 lb. to the square inch. 
Zinc. — M. E. Gatellier, in endeavouring to account for the great loss of 
zinc in the smelting of its ores, finds that much is due to the porosity of 
the retorts in which the operation is carried out, and he succeeded in 
materially reducing the loss by applying a glaze to the exterior of the 
retorts by means of common salt — the same material that is employed in 
glazing in potteries. As a secondary advantage, he points out the less 
injury to the neighbourhood of the works from saving the zinc, which 
would otherwise escape into the atmosphere. Mr. George Darlington 
describes the preparation of zinc-white (oxide of zinc) direct from the 
ore, as it is now practised in America, where the make is from 8,000 to 
10,000 tons annually. The furnaces are similar to coke ovens, with flues 
leading to collecting rooms and chambers of subsidence. The principle 
adopted is to evolve the zinc in the metallic state by the action of the fuel 
(anthracite) upon the ore ; as it rises in vapour it finds oxygen at a very 
high temperature, and is thus converted into oxide. Zinc-white is now in 
great request as a pigment, as a substitute for white lead, over which it 
has many advantages. 
Platinum . — At a scientific meeting held at Bonn, in the beginning of 
April, M. von Dechen produced two fragments of crucibles in which pla- 
tinum had been fused with coke by Dr. Carl Bischof. There was evidence 
of its perfect fusion, and of the great ductility secured. The crucibles 
were made of clay occurring in the coal-measures of Waldenburg, in 
Silesia, discovered by Dr. Bischof in his researches on fireproof clays. 
