Page:Popular Science Monthly Volume 27.djvu/234

220 from particles of the burning element flying around the room, and, settling on articles of copper and iron, covering them with a sulphurous coating.

"The process of using liquid anhydrous sulphurous acid in siphons is free from these inconveniences. The siphons contain 750 grammes of the acid, and one of them is efficient for the disinfection of twenty cubic metres of space. In using the siphons a vessel is set in the middle of the room, and is put in communication with the outside by means of an India-rubber tube passing through a hole in the door. The door having been closed, the orifice of the siphon is inserted into the India-rubber tube, and, the liquid being let in through it, is freely evaporated in the air of the room. This process is very convenient; it avoids the danger of fire, and does not affect metallic objects; and the penetrative force of sulphurous acid thus administered appears to be greater than that of the acid obtained by burning sulphur. The only drawback to its use is the high cost. The siphons are sold to the general public for a dollar each, but can be bought in large quantities



for half that price. Thus the expense of disinfecting a room of one hundred cubic metres with this preparation would be from two and a half to five dollars."

The process of the combustion of bisulphide of carbon was