210 ANNUAL OP SCIENTIFIC DISCOVERY. 



experiraonts to the wondering gaze of Parisian savans. Schon- 

 bein's reply gives us the exact state of his knowledge or belief on 

 the sul)jcet, and is woi'th conininiiicating to English chcniists. 

 He says that he has been engagt-d almost exclusively, and with- 

 out interruption, in the study of oxygim for thirty years, and 

 during this time he has discovered a number of facts which allow 

 of his drawing the following conclusions: 1. That oxygen may 

 exist in three different allotropic states. 2. Two of these states 

 are active, and opposed one to the other: he designates one of 

 them ozone, and the other antozone. 3. Equal ciuantitic^s of 

 ozone and antozone neutralize each other to form ordinary 

 neutral or inactive oxygen. 4. Ordinary neutral oxygen may be 

 split up or transformed, half into ozone and half into antozone. 

 The experimental demonstration of the truth of these conclusions, 

 however, he admits, is not so simple, — as, for examjili', the com- 

 ])osition and tleeomposition of water; and he adds that the (ixpor- 

 iments necessary for their logical deduction would occupy more 

 time than could be devoted to a single lecture. ' Some scientific 

 journals,' says .Schiinlx'in, ' have been badi}' informed, when they 

 asserted that I had succeeded in isolating ozone and antozone ia 

 a state of i)urity. The assertion is without foundation. It is true, 

 that, for a long time, I have; made a great number of attempts to 

 arrive at this desiralde end ; but always without complete success. 

 Ozone and antozone are always mixed with neutral oxygen, from 

 causes closely associated with the generati(3n of the two active 

 modifications.' The Professor concludes his letter by offering to 

 come to Paris, should it still be desired, and if his health permit, 

 and give a short course illustrative of the whole suliject. It is to 

 be hoped he will be invited, and, while here, perhaps he might be 

 induced to go on to London, which I do not think he has visited 

 since the year he announced his discovery of ozone." 



Dr. Daubenj-, before the British Association, ISGfi, made a com- 

 munication on ozone. He considered, first, the dependence of the 

 amount of ozone present in the atmosphere on the direction of the 

 wind, and proved, by tables registering the quantity during a pe- 

 riod of eight months, that in Devonshire it abounded most during 

 those winds which blew from the sea. He then pi-oceeded to show 

 that the ozone present in the air was derived partly, at least, from 

 plants, the green parts of which generate ozone when they emit 

 oxygen. By observations made on fifty-seven species of i)Iants, 

 I'epresenting fort3'-seven natural families, it was concluded that a 

 certain amount of coloration was produced upon Schonbein's paper 

 by leaves during the continuance of solar light, beyond what could 

 have been brought about by light alone, but that this coloration 

 did not go on progressively at any definite rate, and even in cer- 

 tain cases diminished after a longer exposure. Precautions were 

 taken to exclude from the air of the jar any ozone that might come 

 from without. Then the efi'ects produced upon the j^aper placed 

 in tubes ex^josed to different light, and in entire darkness, were 

 noted. It was shown that ozone was generated by the leaves only, 

 and not by the flowers of plants; and, on the whole, it seemed to 

 be fairly presumable that plants are the appointed agents, not 

 only for restoring the oxygen which anim:ils consume, but also 



