224 ANNUAL OF SCIENTIFIC DISCOVERY. 



a whole, the roots produced by the plants under the influence of ozone 

 did not exceed -^ of tho^e produced in its absence, from an equ'il 

 number of healthy seeds. One curious result of the almost total absence 

 of roots was that the wheat plants were scarcely able to sustain themselves 

 in a vertical position; th greater part of them fell over on one side. 

 The flatness of the grains of the maize afforded these plants a better sup- 

 port. The presence of ozone also prevented the usual formation of mold 

 on seeds placed in contact with air and water under a bell-glass. 



The ozone used in the experiments was generated by the action of 

 sulphuric acid upon chameleon mineral. Two or three grains of chame- 

 leon mineral were placed in a small capsule and moistened with oil of 

 vitriol. This when placed by itself, or with a vessel of water under 

 a bell-glass of about three litres capacity, was found to maintain a highly 

 ozonized atmosphere for five or six days or even longer. But as the 

 presence of vegetation would tend to destroy the ozone rapidly, it was 

 considered expedient to renew the generating mixture every two or three 

 days. 



Pasteur has lately shown that the putrefaction and oxydation of 

 organic bodies is effected to a very large extent by the intervention 

 of the lowest order of vegetable organisms. That in some cases 

 where the germs of these bodies have been carefully excluded, milk 

 for example has been kept in the presence of atmospheric air for a 

 year without alteration ; and that when sawdust was enclosed in a llask 

 for a month, the germs having been similarly excluded, the air still 

 contained 16 per cent of uncombined oxygen. It therefore appears 

 that ozone, while a highly oxydizing agent, may in some cases check 

 putrefaction and oxydation by destroying the intermediate agencies, 

 through which these operations are effected ; a fact not without inter- 

 est in connection with the alleged influence of oaone on epidemics. 



Carbonic Acid. Experiments were also made to ascertain the effect 

 of a complete removal of carbonic acid from the atmosphere surround- 

 ing plants. The seeds were placed on gauze strained over a vessel 

 of water, which was set in a dish containing concentrated solution of 

 caustic soda, and the whole was covered with a bell-glass. A similar 

 arrangement was made, exclusive of the caustic alkali, to afford a 

 term of comparison. Xo appreciable difference could be observed. 

 It is probablo that seedlings, within the hight which they can attain 

 under an ordinary bell-glass, still derive a sufficient supply of carbon 

 from the seed. Be this as it may, the removal of carbonic acid from 

 the atmosphere surrounding them did not interfere with their growth. 

 Experiments made with seeds placed in an atmosphere of carbonic 

 acid accorded with results obtained by other observers, as to total 

 prevention of germination under circumstances otherwise favorable. 

 The seeds, however, were found to be not in any way injured, and 

 germinated freely on exposure to the atmosphere. 



It seems probable that in those cases in which germination has been 

 observed to take place in an atmosphere of carbonic acid gas, the ex- 

 clusion of atmospheric air has not been sufficiently well maintained. 



TESTS FOR OZONE. 



Dr. Allnatt says: "I conclude that bibulous paper, saturated with 

 a solution of iodide of potassium and starch or thin arrowroot, affords 



