CHLORINE. This gas was discovered in 1774 by Scheele, who called it dephlo gisticated muriatic acid ; the French no menclaturists afterwards termed it oxygen wied muriatic acid, conceiving it to be a compound of oxygen and muriatie acid. This erroneous view of its nature was corrected in 1809 by Sir H. Davy, who gave it the present name, indicative tf its color. Chlorine is a simple substanc•, existing at common temperatures and pressures iu the state ; but when subjected to a pressure of about foci at mospheres, it becomed condensed iota a yellow transparent hill lid, which is 5. non conductor of electr.city. 100 rnbical inches of chlorine, 4 mean temrmature and pressure, weigh between 7/ and 77 grains : water absorbs twice volume, and acquires a yellow color, the pe culiar suffocating odor of the gas. When humid chlorine is exposed to a tempera ture of 32°, it as:dames a crystalline form ; this hydrate of chlorine consists of 1 equi valent of chlorine = 37 10 of water = 9 + 10 or 90. Chlorine is not only mire spirable, but very injurious when breath ed, even if largely diluted ; a taper burns i In it with a red smoky flame, and is soon extinguished. Some of the metals, when finely divided, spontaneously take fire in chlorine, such as brass leaf, or powdered antimony. A remarkable property of
chlorine is its power of destroying almost all vegetable and animal colors : hence the important application of this gas and of some of its combinations to the art or bleaching. It also destroys the putrid odor of vegetable and ani mal substances, and infectious effluvia of all kinds : whence its use in fumigation, and in preventing the spread of infecti ous and contagious matter, and purifying noxious atmospheres.
The great natural source of chlorine is common, salt, which contains it in the pro portion of about 60 per cent. It is pro cured by decomposing common salt by the joint agency of sulphuric acid and peroxide of manganese. The best pro portions are 3 parts of salt and 1 of oxide of manganese ; these are well mixed, and put into a retort with 2 parts of sulphuric acid previously diluted with 2 of water. Chlorine is evolved, and its extrication is quickened by the application of a gentle heat. Chlorine may also be obtained from a mixture of muriatic acid with half its weight of black oxide of manganese. The gas may be collected over water, and should be preserved in bottles with glass stoppers ; if left in the contact of water it is soon absorbed. (See Mumma° Acin.j