Wells's principles and applications of chemistry; . er-foil,moistened with water, be plungedinto ozone, it rapidly crumbles intodust—oxyd of silver. Ozone dis-places iodine from its combinationswith the metals, setting the iodinefi-ee. This reaction is so easily pro-duced, and is so sensitive, that it fur-nishes the readiest and most dehcatemethod of detecting the presence oftraces of ozone in the air. A slip ofpaper, as before stated, moistened withstarch and iodide of potassium, andinserted in a vessel containing theslightest admixture of ozone, becomes blue from the action of the liberated
Wells's principles and applications of chemistry; . er-foil,moistened with water, be plungedinto ozone, it rapidly crumbles intodust—oxyd of silver. Ozone dis-places iodine from its combinationswith the metals, setting the iodinefi-ee. This reaction is so easily pro-duced, and is so sensitive, that it fur-nishes the readiest and most dehcatemethod of detecting the presence oftraces of ozone in the air. A slip ofpaper, as before stated, moistened withstarch and iodide of potassium, andinserted in a vessel containing theslightest admixture of ozone, becomes blue from the action of the liberated iodine, which immediately unites withthe starch, and forms the blue iodide of starch. One of the most singular circumstances connected with ozone is the effectof heat upon it. A temperature not much higher than boiling water is suf-ficient to destroy it entirely. Advantage is taken of this fact to demonstratethe absolute chemical identity of ozone and oxygen. Ozone passed into oneend of a red hot tube comes out ordinary oxygen at the other end.*. • Respecting this strange condition of allotropism, of -which ozone is a particular ex-ample, Professor Faraday, in a recent publication, remarks:— There was a time, andthat not long ago, when it was held among the fundamental doctrines of chemistry, thatthe same body always manifested the same chemical qualities, excepting only such va-riations as might be due to the three conditions of solid, liquid, and gas. This was heldto be a canon of chemical philosophy as distinguished from alchemy ; and a belief in thepossibility of transmutation was held to be impossible, because at variance with this fun-damental tenet. But we are now conversant with many examples of the contrary ; and,strange to say, no less than four of the non-metallic elements, namely, oxygen, sulphur,phosphorus, and carbon, are subject to this modification. The train of speculation whichthis contemplation awakens within us is extraordinary. If the condition of all
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectchemistry, bookyear18
