288 ANNUAL OF SCIENTIFIC DISCOVERY. 



air to oe ozonized. After a great number of trials, the author has not yet 

 succeeded in establishing with certainty the part taken by ozone in the 

 phenomenon of nitrification, effected in the absence of azotized or ammonia- 

 cal substances, but his experiments have convinced him that the numerous 

 attempts to prove the presence of ozone hi the air, and measure its quantity 

 by means of iodized paper, are not of the least value. 



It is an admitted fact, that the coloration of the paper takes place every 

 day in the country, in places where there is an active vegetation, and espe- 

 cially in the neighborhood of resiniferous trees, whilst repeated observations 

 prove that in the most populous parts of towns the paper is very rarely and 

 very slightly colored. Resiniferous trees, aromatic plants, and all the parts of 

 vegetables which contain volatile oils, act much more strongly than inodorous 

 plants upon iodized paper in then 1 vicinity. By passing moist air through a 

 tubulated bell-glass covering the plants to be experimented on, and exposing 

 the iodized paper to the air at its exit from the bell, it will be seen that when- 

 ever the plant is capable of producing odorous volatile substances, coloration 

 takes place ; in the other case the paper remains white. 



From some experiments recently published, it would appear that the 

 oxygen disengaged by the green parts of plants under the influence of light, 

 is in the same state as the gas produced by the electrolytic decomposition of 

 water, or the nascent oxygen prepared in the cold by the action of sulphuric 

 acid upon binoxide of barium. The author has found that this oxygen has 

 no effect upon iodized paper. He placed some aquatic plants in a bottle filled 

 with Tain water, containing about half its volume of carbonic acid, exposed 

 the apparatus to the sun, and collected the gas under a test tube filled with 

 water ; the gas produced no coloration of iodized paper by contact for six 

 hours. As it might be objected that the gas had lost its oxidizing power 

 during the short space of time occupied in collecting it, he adapted to the 

 neck of the bottle containing the plants, a glass tube of three decimetres in 

 length, covering its lower half with black paper, and introducing a strip of 

 test paper both into this and into the portion left exposed to the light. The 

 apparatus was exposed for two days to the sun ; 2'25 litres of moist gas were 

 evolved, the whole of which passed over the iodized paper, of which the strip 

 protected from the light was unchanged, whilst the other was strongly 

 colored. This is the constant effect of the action of light upon iodized paper 

 hi the presence of moist oxygen. 



It cannot be admitted, as advanced by Schoenbein, and lately repeated by 

 Scouterten, that light ozonizes the air, for although the active modification of 

 oxygen is not permanent, it may be kept for several hours ; and if light pos- 

 sessed the property attributed to it, moist air exposed to the sun and removed 

 for a short time from the action of the solar rays, ought to act upon iodized 

 paper in the manner of ozone, but this is never the case. However long the 

 air may be exposed to the sun, it is never ozonized. 



STRYCHNIA AND ITS DETECTION IN CASES OF POISONING. 



The frequent use of strychnia as a poison has attracted so much attention 

 in Great Britain during the past year, that many careful reinvestigations of its 



