CHEMISTRY. 



state of protoxide, but also facilitates the crys- 

 st'iMii MI' tho boruto of zirconiu, which is 

 hihlo when there is excess of boric 

 Tli.- IK :ul should then bo kept at abright- 

 at, just within the deoxidizing flame, 

 until so much borax has been volatilized that. 

 needle-shaped crystals begin to be de- 

 I, when it must bo allowed to cool 

 r:i[>iilly. It should then be transparent, with 

 rod crystals, and tho uranium all in tho 

 of protoxide. On gently reheating it, 

 the boad ought to suddenly turn white and al- 

 opaque ; and care must be taken not to 

 lu-;vt it any more than is just requisite to cause 

 tin- borate to crystallize out, or else the uranium 

 will rapidly pass into the state of peroxide. 

 Such beads must be examined by strong direct 

 light from the sun, or from a lamp of very 

 great brilliancy, condensed on them by means 

 of an almost hemispherical lens of about $ inch 

 focal length ; and, in addition to the means de- 

 -.:! in my former paper, I have since found 

 it very convenient to place them over a hole 

 in a black card, so as entirely to prevent the 

 jia^age of any light which has not penetrated 

 through them, even when so arranged in tho 

 focus of the microscope that the spectrum of 

 t heir thin edges may be examined, if the centre 

 be too thick and opaque. If thus properly 

 prepared, the presence of more or less uranium 

 will bo shown by the greater or less intensity 

 of the absorption-bands of the spectrum de- 

 scribed in my former paper. This test is so 

 delicate that there is no difficulty in seeing the 

 darker band in the green in the case of zircons 

 which contain no more than one-tenth per cent. 

 of uranic oxide ; and I find that very few lo- 

 calities yield this mineral so free from it that 

 it cannot be easily detected. Those from Mi- 

 ask, Siberia, are the only specimens in which 

 I have not been able to recognize it. The 

 jargons from Ceylon contain an amount vary- 

 ing up to about one per cent., although in no 

 published analysis that I have seen is there any 

 allusion to the presence of even a trace." 



Ozone. O. Loew, in a contribution to the 

 Zeitachrift far Chemie, after referring to the 

 well-known instances of the formation of ozone 

 during slow combustion and oxidation, gives the 

 opinion that every act of oxidation, whether 

 slow or rapid, is accompanied by the formation 

 of ozone just previous to the combination be- 

 tween the substance to be oxidized and the 

 oxygen, a state of great activity taking place. 

 The following experiment is described to prove 

 this dictum : A current of air is blown through 

 a rather wide glass tube toward the flame of 

 a Bunsen gas-burner ; and opposite the end of 

 the tube, which is directed toward the flame, 

 a suitably-sized beaker-glass is held ; and, after 

 a few seconds, the blowing is discontinued, 

 and the beaker -glass simultaneously covered 

 with a gloss plate. When the air contained in 

 the beaker-glass is tested, it will be found to 

 emit the peculiar odor of ozone, to blue guaia- 

 cum-paper, and to separata iodine from iodide 



of potassium. Tho formation of ozone is great- 

 est when the current of air is so strong as 

 nearly to cause the extinguishing of the flame. 

 Tho experiment succeeds with every other 

 kind of flame, provided care be taken so to 

 regulate tho current of air as to exclude tho 

 presence of intermediate products of combus- 

 tion, as, for instance, vapors of partly-consumed 

 alcohol, if a spirit-flame be used. The author 

 draws from his researches tho following con- 

 clusions: 1. Oxygen is first converted into 

 ozone in every cose where active combustion 

 takes place. 2. Far more ozone is formed than 

 is required for the keeping up of the process of 

 complete combustion and oxidation of the oxi- 

 dizable material. This surplus of ozone is, in 

 all ordinary cases of combustion, destroyed, 

 partly by the high temperature, and partly by 

 the rush of cold air, and draught thereby 

 caused, attending the combustion. 



M. August Honzeau gives a new method for 

 tho preparation of ozone, by treating binoxido 

 of barium with sulphuric acid. The oxygen 

 given is strongly ozonized. 



M. J. Jonglet has ascertained that nitro- 

 glycerine, dynamite, iodide of nitrogen, chlo- 

 ride of nitrogen, and some other similar com- 

 pounds, explode the very moment they are 

 brought into contact with ozone : so that, for 

 instance, a drop of nitro-glycerine, introduced 

 into a vessel containing ozone, causes an in- 

 stantaneous explosion. Picrate of potash gun- 

 powder and ordinary gunpowder are slowly 

 decomposed by ozone, a decomposition which, 

 as regards the last-named substance, takes 

 several weeks before it is perceptible. 



Chemical Action of Sunlight. M. Bontemps, 

 managing director of the crystal-glass works at 

 Choisy le Roi, France, has found that within 

 three months of exposure to sunlight the best 

 and whitest glass made at St. Gobain is turned 

 distinctly yellow ; extra white glass (of a pe- 

 culiar manufacture) becomes even more yellow, 

 gradually assuming a color known as pelure 

 d'oignon; glass containing 5 percent, of litharge 

 is also affected, but far less perceptibly ; crystal 

 glass made with carbonate of potash (the other 

 varieties referred to contain carbonate of soda), 

 litharge, and silica, not at all affected. English 

 plate-glass, made by the British Plate-Glass 

 Company, and exhibiting a distinctly azure- 

 blue tinge, remains also unaffected. The author 

 attributes this coloration, which begins with 

 yellow and gradually turns to violet, to the 

 oxidizing effect of the sun's rays upon the pro- 

 toxides of manganese and iron contained in 

 the glass. 



A contributor to the American Gas- Light 

 Journal writes: "Wo know that the plants, 

 under tho influence of tho sunlight, reduce 

 within their substance carbonic acid and water 

 to organic compounds and organized tissues. 

 We know further that the albuminous parts as 

 well as some essential oils of plants contain 

 sulphur, which doubtless comes from the sul- 

 phates contained in the soil. As regards this 



