176 ANNUAL OF SCIENTIFIC DISCOVERY. 



the gas of the carbonic acid to a certain extent, render experiments 

 on the subject desirable. Such experiments were made in the 

 year 1863 by Prof. W. B. Rogers, assisted by Mr. Fred. E. Stirap- 

 son, present Inspector of gas and gas-meters for the State of Mas- 

 sachusetts. The experiments were performed by mixing ordinary 

 Boston illuminating gas (containing about 2.5 per cent, of car- 

 bonic acid on the average) with different quantities of carbonic 

 acid, and burning first the ordinary gas and then the mixture in 

 the same 15-hole argand burner, the gas in both cases being passed 

 at the same rate (5 feet per hour) through the same dry meter. It 

 was found that the gas for every additional per cent, of carbonic 

 acid lost 6 percent, of its illuminating power up to a certain point, 

 and that further addition of carbonic acid caused further decrease, 

 but in a smaller ratio. All light was destroyed by the addition 

 of 58 per cent, of carbonic acid. Fred. E. Stimpson, at the Troy 

 Meeting of American Association. 



The non-luminosity of the Bunsen flame is not due, according to 

 Knapp, to the fact that the mixture of air and gas affords a more 

 complete combustion of the latter. He finds that chlorhydric 

 acid, carbonic acid, or even pure nitrogen, causes the same effect, 

 and therefore believes that the loss of light is due partly to the 

 cooling of the flame, but mainly to the dilution of the gas. Journ. 

 fur prakt. Chemie. 



CONDITION OF CARBON AND SILICON IN IRON AND STEEL. 



At a meeting of the Iron and Steel Institute held at Merthyr 

 Ty civil, in South Wales, in September of the last year (1870), Mr. 

 G. J. Snelus read a paper with the above title. This paper con- 

 tained the results of a long course of experimental inquiry, in- 

 stituted with a view to determine the conditions in which the two 

 non-metallic bodies, carbon and silicon, exist in iron and steel. 

 Dr. Perry had said, in his celebrated work on "Iron and Steel," 

 that not a trace of graphite could be detached by the point 

 of a pen-knife from the fractured surface of highly graphitic 

 iron ; but Mr. Snelus had proved the incorrectness of this state- 

 ment by examining some pig iron which had cooled slowly under 

 a mass of slag, and which had in consequence very large crystals. 

 From the surfaces of these crystals the graphite could not only 

 be separated with the point of a pen-knife, but even with the 

 finger-nail ; and when the graphite was removed the iron under- 

 neath rusted rapidly in a damp atmosphere. 



By pulverizing pig iron and then using the magnet, a consider- 

 able amount of graphite was separated. In spiegelcisen the 

 carbon was found to be almost wholly combined. The author 

 had never found as much as 5 per cent, of combined carbon in 

 pig iron, although many analyses had been published in which 

 the carbon was put down at even 6 per cent. According to Mr. 

 Snelus there is no pig iron that is destitute of silicon, and he had 

 never met with a case in which either steel or wrought iron was 

 totally free from it. Good Bessemer and tool steel rarely con- 



