Elements of chemical philosophy : on the basis of Reid, comprising the rudiments of that science and the requisite experimental illustrations, with plates and diagrams.

  • Mitchell, Thomas D. (Thomas Duché), 1791-1865.
Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemical philosophy : on the basis of Reid, comprising the rudiments of that science and the requisite experimental illustrations, with plates and diagrams. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    To understand the process, it is proper to say, that 70 is the combining or equivalent number of chloric acid, which united to 48, the equivalent of potash, make 124, or one equivalent of chlorate of potash. The chloric acid is composed of oxygen and another simple body called chlorine; while potash is a com- pound of oxygen and a metal, named potassium. Thus, 76 chloric acid = 36 chlorine + 40 oxygen. 48 potash = 40 potassium -j- $ oxygen. 124 chlorate of ) 76 chloride of ) 48 oxygen. potash. ^ — potassium. 5 — Of course, all the oxygen contained in the chloric acid as well as in the potash,is driven off, amounting to 48 parts; while the chlorine of the acid and the potassium of the potash, unite to form 76 parts of chloride of potassium. The latter remains in the retort, and being soluble in water, is easily removed. In addition to the above modes for preparing oxygen gas, we may obtain it, by means of the green leaves of vegetables, im- mersed in an inverted jar full of water, and placed in the sun- shine. The appearance of oxygen gas, in this process, is va- riously explained. Some say, that the water is actually decom- posed, its hydrogen taken in by the plant, while the oxygen is liberated. Others affirm, that the oxygen is obtained by the decomposition of carbonic acid, which is present, the carbon being taken up by the plant, and the oxygen evolved. Dr. Manners, of New Jersey, performed some experiments in 1812, to prove this theory.*' When lime water was employed, instead of pure water, no oxygen was obtained; the same thing occur- red, if the water was boiled before the leaves were placed in it. Now, in the first case, all the carbonic acid was seized by the lime; and in the latter, it was expelled from the water by heat. In addition to the properties of oxygen already named, we may affirm,that it has neither acid noralkalincqualities,foritdoes not redden, nor turn green the vegetable blue colors, nor does it evince any tendency to unite with acids or alkalies. For most of the simple bodies it has a strong attraction, and is suscepti- ble of union with all of them. The act of combining with oxy- gen, is sometimes called oxydation and also oxygenation,and the bodies resulting from this union, arc said to be oxydiscd and oxygenated; they are also called oxydes, and some of them acids. Many bodies acquire oxygen from the air, if moisture be present. Thus, iron soon passes into rust, and green copperas is * See Memoirs of the Columbian Chemical Society.