331 bleached are dipped. They are stirred about with a glass rod from time to time, and after about ten minutes they are taken out of the bath, strongly colored of a violet brown hue by an abundant deposit of oxide of manganese. They are then dipped as quickly as possible in a bath of water, acidulated with sulphurous acid, and again stirred and turned over with a glass rod, and after two or three minutes the materbt]s or thread, originally of yellow or gray color, are already white. These

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... tions are repeated twice too-re, and the result is a brilliant white, whilst the fibres are in no way injured. The materials operated upon were cotton fabrics, dirty as they came direct from tLe loom, as well as skeins'of linen thread of a dark slate-color, which, by existing pro-cesses~ would have taken many days to bleach. Meehanlcs, .Physics, and Chemistry. Hydrogen, you perceive, is the most powerful thermotle agent, and carbonic oxide is the weakest. A pound of the first of these gases will raise 62,030 lbs. of water 1 °, whereas a pound of the latter will only heat about 4ti25 lbs. of water to that extent. Examined by the cubic foot, and considering that for every pound of water raised 1 °, about 48 cubic feet of air are raised to the same extent, we may say the chief constituents of coal gas have this thermotic power--