64 ANNUAL OF SCIENTIFIC DISCOVERY. 



IMPROVEMENTS IN IRON SMELTING. 



THE mode of smelting iron consists in mixing the ore with lime and 

 coal ; the former producing a glass or slag with the impurities of the 

 ore, while the coal reduces the oxide of iron to its metallic state. 

 Much heat is required in the process of smelting, but the cold air 

 blown in, as the blast, lowers the temperature and compels the addi- 

 tion of fuel, as a compensation for this reduction. Science pointed to 

 this loss, and now the air is heated before being introduced to the 

 furnace. The quantity of coal is wonderfully economised by this 

 application of science ; for instead of seven tons of coal per ton of 

 iron, three tons now suffice, and the amount produced in the same 

 time is nearly sixty per cent, greater. Assuredly this was a great 

 step in advance. Could Science do more ? 



Prof. Bunsen, in an inquiry, in which I assisted, has shown that she 

 can. We examined the furnaces, in each portion of the blazing 

 mass, so as to fully expose the operation in every part of the blazing 

 structure. This seemingly impossible dissection was accomplished by 

 the simplest means ; the furnaces are charged from the top, and the 

 materials gradually descend to the bottom ; with the upper charge a 

 long graduated tube was allowed to descend, and the gases streaming 

 from ascertained depths, were collected and analyzed. Their com- 

 position betrayed with perfect accuracy the nature of the actions at 

 each portion of the furnace, and the astonishing fact was elicited, that, 

 in spite of the saving produced by the hot blast, no less than 81 per 

 cent, of fuel is actually lost, only 18^ per cent, being realized. If, in 

 round numbers, we suppose that four-fifths of the fuel be thus wasted, 

 no less than 5,400,000 tons are every year thrown uselessly into the 

 atmosphere ; this being nearly one-seventh of the whole coal annually 

 raised in Great Britain. This enormous amount of fuel escapes in the 

 form of combustible gases capable of being collected and economised ; 

 yet in spite of well ascertained facts, there are scarcely half a dozen 

 furnaces in Great Britain, where this economy is realized by the utili- 

 zation of the waste gases of the furnace. 



Large quantities of ammonia are annually lost in iron smelting, 

 which might readily be collected. Ammonia is constantly increasing 

 in value, and each furnace produces and wastes at least one cwt. of its 

 principle salt daily, equivalent to considerable money lost. Prof. 

 Play fair, on the Results of the Great Exhibition. 



THE MINIE RIFLE. 



THE following is a description of this weapon, which has lately been 

 ntroduced into the British service. The Minic musket or rifle, most 

 approved and ordered to be generally introduced into the service, is 

 a remarkably well finished article, and lighter and more easily used 

 than the previous percussion muskets. The Minie rifle has four 

 grooves inside, and the mode of loading it is first to bite off the twisted 

 waste paper at the end of the cartridge, pour in the powder at the 



