546 
POPULAR SCIENCE REVIEW. 
mended the Secretary of the Navy to introduce the oil on board one of the 
Government steamers to determine accurately its economical efficiency. 
As the rapidity of evaporation does not always correspond proportionally 
with the quantity of water evaporated by each pound of coal, it would be 
interesting to know the number of pounds or gallons of water evaporated 
by each gallon of petroleum, and the additional danger, compared with 
coal, attending its use, because many of the great steam-boat accidents 
on the American rivers have been traceable to the careless use of tur- 
pentine (a less explosive material) for the same purpose. The advocates 
for the introduction of petroleum as a substitute for coal contend that, in 
a vessel like the Cunard steamer Persia , the saving, taking into account 
the smaller space required, and all other advantages, would amount to 
<£2,400 for each trip. Experiments on a larger scale will, it is said, speedily 
be made in an ocean steamer, by a company, to whom the present trustees 
are about to transfer their rights. In addition to the discovery of con- 
siderable deposits of the oil in Southern Russia, large quantities are 
alleged to have been found on the Pacific in California. The calculations 
as to economy, however, seem to have been based upon the assumption 
that the price would remain as now, after the increase of demand, and 
also upon the cost of coal in America and not in England. It is alleged 
that its use will be a great saving not only for merchant steamers, but 
that a naval steamer using it can keep the sea under steam three times 
as long, and with less labour and greater economy as compared with an 
equal weight of coal. — Vide Mining and Smelting Magazine , Vol. v. No. 29. 
A New Coal Mine has recently been discovered near La Pa z, in 
California. This discovery must necessarily be of great value to the 
Colerado copper mines, which have been rather imperfectly worked of late, 
owing to the great scarcity of fuel. 
Imports of the Metals. — From the reports of the Board of Trade for the 
two months, ended on the 29tli of February last, we perceive that with 
the exception of brimstone, copper-regulus, tin, and pyrites, there has been 
a decided increase in the quantity of mineral matter imported this year 
over that of last year. 
Improved Cast-Iron . — It has recently been demonstrated that cast-iron 
composed of old and new metals in certain proportions, calculated to give 
it a great power of resistance, acquires a new degree of strength by an 
addition of 2 per cent, of wolfram or tungsten. In one of the combinations 
thus made, the increase of the power of resistance to fracture per square 
centimetre, was 44 kilogrammes with French w r olfram. In another, formed 
of one-third of old English cast-iron, and two-thirds of old ordnance, the 
.increase, with German wolfram, was 67 kilogrammes per square centi- 
metre. M, Leguen has just shown that, when subjected to a second 
fusion, cast-iron containing wolfram is still superior to other cast-iron 
similarly treated. After this operation, the difference of resistance in 
favour of the former was 26 kilogrammes per square centimetre ; and 
German wolfram is superior to French, even after a second fusion. A 
third fusion of the same cast-iron having been directly effected in a 
Wilkinson’s furnace, instead of being done in a crucible as in the preceding- 
cases, the tenacity of wolframed cast-iron was again greater than that of 
the common sort treated in the same manner. Hence it may be concluded 
