2i 8 THE POPULAR SCIENCE MONTHLY. 



The charge of a puddling-furnace, consisting of 500 pounds of pig- 

 metal and eighty pounds of " fix," produces with coal-fuel 490 to 500 

 pounds of iron. With gas for fuel, it is claimed that the same charge 

 will yield 520 to 530 pounds of iron. In an iron-mill of thirty fur- 

 naces, running eight heats each for twenty-four hours, this would 

 make a difference in favor of the gas of, say, 8 X 30 X 25 = 6,000 

 pounds of iron per day. This is an important item of itself, leaving 

 out the cost of firing with coal and hauling ashes. 



For generating steam in large establishments, one man will attend 

 a battery of twelve or twenty boilers, using gas as fuel, keep the 

 pressure uniform, and have the fire-room clean as a parlor. For burn- 

 ing brick and earthenware, gas offers the double advantage of free- 

 dom from smoke and a uniform heat. The use of gas in public bak- 

 eries promises the abolition of the ash-box and its accumulation of 

 miscellaneous filth, which is said to often impregnate the " sponge " 

 with impurities. 



In short, the advantages of natural gas as a fuel are so obvious to 

 those who have given it a trial, that the prediction is made that, should 

 the supply fail, many who are now using it will never return to the 

 consumption of crude coal in factories, but, if necessary, convert it 

 or petroleum into gas at their own works. 



It seems, indeed, that, until we shall have acquired the wisdom en- 

 abling us to conserve and concentrate the heat of the sun, gas must be 

 the fuel of the future. 



USE OF SULPHUROUS DISINFECTANTS. 



By GASTON TISSANDIEE. 



AMONG the most convenient and efficacious substances to be used 

 for purposes of disinfection are sulphurous acid and bisulphide 

 of carbon. The question of the merits of these substances and the 

 advantages of using them was recently considered, in the "Journal de 

 Pharmacie et de Chimie," by M. Alfred Riche, who said : " M. Dujar- 

 din-Beaumetz recently requested the concurrence of MM. Pasteur and 

 Roux in instituting new experiments on the value of disinfectants, and 

 has just published the results of the same in the ' Bulletin ' of the 

 Academy of Medicine. Two rooms of about a hundred cubic metres 

 capacity were selected in the wooden barracks attached to the hoj)ital 

 Cochin. The walls of these rooms, made of jointed planks, gave pas- 

 sage to the air through numerous cracks, although the precaution had 

 been taken of stopping the larger ones with paper. Each of the 

 rooms was furnished with a bed, the usual furniture, and cloths of 

 different colors. Bromine, chlorine, and sulphate of nitrosyle were 

 successively rejected. Three sources of sulphurous acid were experi- 



