CHEMISTRY. 285 



nized, rarely showing a less amount than that corresponding to 5 on Schoen- 

 bein's scale, often attaining 9, and occasionally even reaching the maximum 

 or 10. In only a single instance, throughout the summer, was there an entire 

 absence of effect. In this series the mean for E. winds was somewhat greater 

 than that for the opposite currents, the former being 7 -6, and the latter 6 -7 of 

 Schoenbein's scale. 



The almost entire absence of ozone in easterly winds at the Boston station, 

 and its presence hi those from the west and north-west, Professor R. ascribed 

 to the circumstance that the former, hi order to reach the place of observa- 

 tion, had to traverse a wide extent of the densely built city, while those 

 coming from westerly points reached the common with but little intermixture 

 of air from streets or buildings. 



In all these observations it was remarked as a general result, that the effect 

 on the test, both as to rapidity and amount, was somewhat in proportion to 

 the velocity of the moving air. Numerous instances were noted of a light 

 breeze continuing for several hours, with but a small impression on the paper, 

 while the strong wind which followed from the same quarter, produced, in a 

 single hour, the most marked effect. Indeed, in very gusty days the impres- 

 sion was so quickly made, and so strong, as to render necessary the renewal 

 of the test paper several times within the twelve hours. 



This increase of ozonic effect with the velocity of the .wind, Professor R. 

 considered to be mainly due to the larger amount of air brought in contact 

 with the test in a given time. In this view the fact becomes very important, 

 as showing the great imperfection of the common mode of observation, even 

 for purposes of rude comparison, since in observing successively, hi a calm 

 and in a high wind, we are hi fact comparing the amount of ozone hi vastly 

 different quantities of ah'. To avoid this error, some means should be 

 adopted for furnishing to the test equal quantities of ah" in equal times. 

 Such a result would be secured by an aspirating apparatus, having a small 

 chamber in the path of the current to receive the test. Such an arrangement, 

 capable of bringing into action a large volume of ah 1 in a short time, would 

 doubtless detect ozone in a multitude of cases, where the common observa- 

 tion in calm air would show none. It would also enable us to make hourly 

 or even half-hourly observations, instead of waiting for the slow development 

 of the action through half a day ; a process which, instead of summing up 

 the ozone actions of twelve hours, allows the effect of one period to be more 

 or less obliterated by that which follows. 



On Ozone and its Relation to Mushrooms. It is well known that certain 

 varieties of mushrooms possess the remarkable property of turning rapidly 

 blue, when their head and stem happen to be broken and exposed to the air. 

 This matter has attracted the attention of Schoenbein, who offers the following 

 explanation. He considers oxygen, both in its free and bound state, to be 

 capable of existing hi two conditions the ozonic or active, and the ordinary 

 or inactive condition. All the oxy-compounds yielding common oxygen at a 

 raised temperature he considers to contain ozonized oxygen, and he further 

 believes that the disengagement of common oxygen from those compounds 

 depends upon the transformation of the ozonized oxygen into the inactive one. 



