422 Progress in Science. [July 



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latent, and is wasted by volatilising the solid. When zinc, iron, or manganese 

 are burned, the resulting oxide is a dense solid ; little or no heat is wasted, as 

 it is not turned into vapour. In addition to this, the inventor obtains the 

 cosmical heat latent in the oxygen of the atmosphere, and the result is that 

 one pound of zinc will evaporate more than four times as much water as one 

 pound of coal, the advantage of which on long sea voyages is obvious. The 

 zinc or other metal thus becomes a vehicle of power, much larger than can be 

 obtained from the same weight or bulk of coal, and the oxide of the metal may 

 subsequently be economically reduced at any convenient place where coal is 

 accessible. The following is the manner in which it is proposed to carry out 

 this invention : — The furnace of the boiler is divided into two or more parts, 

 first, the hearth or grate on which the metal is burned (in this description we 

 will confine ourselves to the metal zinc) ; secondly, a chamber behind the 

 hearth to collect the oxide. In the case of tubular boilers, the heated gas 

 from this chamber is made to circulate through the tubes. The furnace has 

 the bottom and sides, and sometimes the top also, of brick, fire-clay, or any 

 other refractory substance. The air is admitted over the combustible metal, 

 or by a blast through the same ; in the latter case pipes or tuyeres are built in 

 the bottom or sides of the furnace. 



The extinction of fire by gas is probably about to be carried out in New 

 York, a company having been proposed for this object. The following is the 

 purport of the scheme: — The company proposes to build, in some central 

 location, a reservoir similar to the gasometer of a gas-house, of sufficient 

 capacity for all emergencies, and run a four-inch pipe therefrom in every 

 direction through the streets, having in front of every door a valve, to which a 

 small rubber hose can be easily attached, by which the stream of gas can be 

 directed to any room on fire. To furnish such a reservoir, with its necessary 

 retorts for making gas, and laying 200 miles of pipe through the city, will come 

 within a cost of 250,000 dollars, and the company claims that the saving of 

 property which water destroys and gas leaves untouched, would more than 

 pay the entire cost in one year, to say nothing of the saving of the buildings. 

 From the reservoir, through the pipes, carbonic acid gas will be forced to the 

 endangered building. Repeated experiments have shown that fire cannot 

 burn in an atmosphere containing one-fifth part of its volume of this gas, and 

 that its presence does not injure the finest fabrics, or discolour the most highly 

 polished plate ; consequently it does no damage to goods or furniture, which 

 water destroys. It can be manufactured at so low a price that the flames of a 

 moderate-sized building on fire could be extinguished for a few dollars. Its 

 use has been frequently endorsed by insurance companies. Up to the present 

 time the difficulty in making use of carbonic acid gas for extinguishing fires 

 has been found in the production and application of this gas in sufficient 

 quantities for obtaining a practical advantage at a real fire. Experimentally 

 the presence of this gas in quantity proportionate to a flame has been found to 

 insure its sudden and complete extinction ; but until within the last few months 

 no plan has been put in operation to make this power available. In 185 1 a 

 coal mine in England, that had been on fire for thirty years, and had extended 

 over twenty-six acres, was completely extinguished by injecting only 8,000,000 

 cubic feet of carbonic acid gas. Water and chemical solutions had been tried 

 in every way and quantity for years upon these burning acres of coal, without 

 any perceptible effect, for the intense heat would drive them back as a volcano 

 sends out its lava into the heavens. The loss by water, caused by the engines 

 playing after a fire is out, or nearly so, is very great. Once in operation, a 

 steam fire engine is frequently as destructive as the conflagration itself. If 

 the new method succeeds and is generally adopted, many of the calamities and 

 losses that are yearly chronicled will cease. As the pipes will be immediately 

 laid and a reservoir built, it is expected that very soon the new apparatus and 

 plan will be practically tested. 



The effect of cold upon iron and steel has formed the subject of a numerous 

 series of experiments which have recently been communicated to the Literary 

 and Philosophical Society of Manchester. The result of these experiments 



