Miscellaneous Intelligence. 



141 



2. On Ozone in the Atmosphere ; by W. B. Rogers, (Proc. Bost. Soc. 

 Nat. Hist., v. 319.) — In making his observations, Prof. Rogers uses the 

 prepared paper and scale of colors of Schonbein's Ozonometer, which, 

 although imperfect as a means of comparison, is the best for practical 

 use yet devised. The slip of paper is suspended out of doors in a box 

 open only at the bottom, so as to be shielded from the rain and snow, and 

 from strong light, at the same time that it is freely exposed to the air. 

 Usually, it is allowed to remain in this position for twelve hours, when it 

 is removed for observation, and a fresh slip substituted ; but when there 

 are indications of a great prevalence of ozone, the test is examined, and 

 renewed at shorter intervals. 



On comparing the recorded observations for the past six weeks, Prof. 

 Rogers has been struck with what seems to be a fixed relation between the 

 direction of the aerial current and the amount of ozone prevalent at the 

 time. As long as the wind continued to come from Eastern or South- 

 ern points, he found the ozone to be nearly or quite absent, but when- 

 ever the current has changed to West or Northwest, the test-paper un- 

 failingly indicated its presence in considerable force. The rapidity and 

 amount of this effect has always been greatest when the wind has hauled 

 suddenly to West and North, and has blown violently, but it has contin- 

 ued to manifest itself, although with slow abatement, as long as the cur- 

 rent held from this quarter. 



To illustrate this effect, Prof. Rogers referred to examples within the 

 present month, (February.) Thus, on the 11th, the wind being light 

 from WbyS and SW, there was no indication of ozone, and during 

 the morning of the 12th, the wind continuing from the same general 

 quarter, furnished a like negative result. About 1 p. m., however, the 

 current changed suddenly to NW, with a snow squall, after which it 

 continued to blow in gusts in the same direction until late at night. Two 

 hours after this change, viz : at 3 p. m., the test-paper was found to be 

 charged with ozone to the amount of y 7 ^ of the maximum of Schon- 

 bein's scale, and at 10 p. m., a second paper which had been freshly sub- 

 stituted for the former, gave T 8 <y. Again, on the 15th and 16th, the wind 

 blowing from S, and SbyW, showed no ozone; retaining the same 

 general direction through the night of the 16th, and part of the following 

 morning, it gave a like negative result. About 11 a. m. of the 17th, the 

 wind hauled towards West, and about 1 p. m., it began to blow strong 

 from WbyN, after which it continued gusty from this quarter and NW 

 until late next day. The test-paper hung out at 9 a.m., of the 17th, 

 was found at 1 p. m., or two hours after the change, to present ozone 

 amounting to ; and another substituted at that time, showed at 5 p. m., 

 or five hours after, a change measuring more than y 8 ^. 



Although the observations thus far made have indicated the prevalence 

 of ozone in connection with winds from W and NW, and its absence 

 in the case of those moving from the opposite quarters, they have been 

 continued far too short a time, and have been too local, to warrant any 

 positive inference of a general kind. The development of ozone in the 

 air being probably dependent on temperature, relative dryness, solariza- 

 tion, electricity and other physical conditions which are perpetually 

 changing, we cannot hope to read precise laws in regard to its production 



