and on Nitrification. 467 



production of ozone by purely chemical means, the whole secret 

 consists in dissolving pure manganate of potash in pure oil of 

 vitriol and introducing into the green solution pure peroxide of 

 barium, when ozone mixed with common oxygen will make its 

 appearance, as you may easily perceive by your nose and other 

 tests. By means of the ozone so prepared, I have rapidly oxi- 

 dized silver at the temperature of —20° C, and by inhaling it 

 produced a capital " catarrh." 



Regarding nitrification, the most important fact I have dis- 

 covered is the generation of nitrite of ammonia out of water and 

 nitrogen, i. e. atmospheric air, which is certainly a most won- 

 derful and wholly unexpected thing. To state the fact in the 

 most general manner, it may be said that the salt mentioned is 

 always produced if water be evaporated in contact with atmo- 

 spheric air. This may be shown in a variety of ways. Let, for 

 instance, a piece of clean linen drenched with distilled water dry 

 in the open air, moisten it then with pure water, and you will 

 find that the liquid wrung out of the linen and acidulated with 

 dilute sulphuric acid (chemically pure) will strike a blue colour 

 with starch-paste containing iodide of potassium, — by the by, 

 the most delicate test for the nitrites. It is therefore a matter 

 of course that shirts, handkerchiefs, table-cloths, in fact all linen, 

 &c, must contain appreciable quantities of nitrite of ammonia ; 

 and if the chemistry of England be not entirely different from 

 that of Switzerland, you will find the same thing at the Royal 

 Institution. The purest water, suffered to evaporate sponta- 

 neously in the open air, will after some time have taken up 

 enough nitrite of ammonia (continually being formed at the eva- 

 porating surface) to produce the nitrite reaction. If you make 

 use of water holding a little potash, or any other alkali, in solu- 

 tion, the same result will be obtained, i. e. the nitrite of that 

 base will be formed (of course in small quantity). The most 

 convenient way of performing the experiment is to moisten a bit 

 of filtering-paper with a dilute solution of chemically pure pot- 

 ash, &c, and to suspend it for twenty-four hours in the open air. 

 On examining the paper it will be found to contain a perceptible 

 quantity of a nitrite, which by a longer exposure of course in- 

 creases. But you may still more rapidly convince yourself of the 

 correctness of my statements, if you heat pure water to a tempe- 

 rature of 50° or 60° C. in a porcelain basin, and suspend over 

 the evaporating surface bands of filtering-paper soaked with a 

 weak solution of potasb, soda, or the carbonates of these bases. 

 Within a very short time (in ten minutes or so) there will be 

 enough of the nitrite accumulated in the paper to produce the 

 reactions of that salt. I enclose a bit of paper treated in that 

 way for a couple of hours, and by laying it upon a watch-glass 



212 



