SCIENTIFIC SUMMARY. 
405 
chances of fracture are reduced to the smallest number. It consists of an 
insulated wire, to which the usual fuse-tube is attached, and has a second 
wire, uninsulated, coiled round it, so that its extremity is about a centi- 
metre from that of the first. Finally, there is a bag attached to its 
extremity, containing the explosive compound. When an induced current 
is passed through the wires, the spark traverses the powder contained in 
the pouch: it melts the tin thread employed to complete the circuit, and 
passes through both wires. By adopting this process a great number of 
blasts can be exploded simultaneously, as there may be branch wires from 
the main stem to various other localities. 
Action of Manganese in the Smelting of Iron . — In concluding a memoir, 
presented to the Royal Academy, on this subject, M. II. Caron observes 
that, in mixing with their ordinary ores those which contain large quan- 
tities of manganese, with a view to the improvement of the products, 
iron-masters may with advantage gradually increase the proportion of 
flux, without rendering their slag less liquid to any injurious extent. 
He recommends the employment of sea-salt, or chloride of calcium, 
when the flux becomes difficult to manage. He also suggests the use 
of fiuor spar or cryolite, but states his objection to these substances, on 
the ground of their containing considerable quantities of phosphoric acid, 
which is exceedingly destructive of cast-iron. 
Manufacture of Copper . — A patent for the separation of copper from 
regulus has been granted to Mr. Fleitmann, a Prussian. His process is as 
follows: — Having obtained an ore which contains, as impurities, only 
arsenic, antimony, and phosphorus, he grinds it to powder, and roasts it; 
and the crude oxide which he obtains in this way is moistened with a 
solution of caustic alkali, dried and again heated, avoiding a temperature 
sufficiently high to fuse the oxide of copper, but at the same time employ- 
ing one adequate to fuse the alkali. By this process metallic impurities 
are got rid of ; and when the mass is mixed with water and washed, the 
pure metal may be obtained from the oxide, either by carbon, or by carbon 
and hydrogen conjointly. — See Chemical News, January 23. 
Oil-lamp Furnace for Melting Metals at a White Heat . — It may seem 
almost surprising that a sufficient temperature can be produced from the 
combifstion of oil to fuse metals, yet such is really the case. In the Chemical 
News for January 2nd a description will be found of a furnace of this 
kind, which has been contrived by Mr. Charles Griffin. It is most inge- 
niously constructed, sold at a moderate price, and must prove invaluable 
to those engaged in the pursuit of metallurgical studies, in localities where 
coal-gas cannot be had. The oil used is of the mineral or rock kind, and 
the combustion of a quart of this (which costs only ninepence) gives a 
heat sufficient to fuse five pounds of cast iron. The furnace being cold 
when an operation is commenced, it will melt a pound of cast-iron in 
twenty-five minutes, lb. in thirty minutes, 4 lb. in forty-five minutes, 
and 5 lb. in the course of a single hour. This furnace possesses one 
peculiar advantage over the coal-gas forms ; viz., platinum crucibles 
remain uninjured, as the rock oil in combustion gives off no sulphureous 
vapours. 
VOL. Ill, — NO. XI. 
2 
