518 [April 16, 



The following communications were read : 

 1. "On Ozone." By E. J. LOWE, Esq., F.R.A.S., F.L.S. 

 Communicated by Sir J. F. W. HERSCHEL, Bart. Received 



March 16, 1863. 



(Abstract.) 



This paper consists of two parts, viz. : 



1 . On the precautions necessary in ozone observations, and on cer- 

 tain corrections requisite before the actual amount can be determined. 



2. The discovery of dry ozone powders as a substitute for the ordi- 

 nary tests ; an investigation into the ozone paper tests of M. Schon- 

 bein and Dr. Moffat, the determination of a proper formula for the 

 tests, with an account of various observations and experiments made 

 on the subject. 



PART I. 



At the last Meeting of the British Association I read a paper on 

 the precautions and corrections requisite in order that a more perfect 

 knowledge of ozone might be obtained. These precautions comprise 

 uniformity of observation, each observer using the same box and the 

 same tests, suspended at the same height, and as nearly as possible 

 placed under the same circumstances. The corrections necessary 

 are: 1st, For the velocity of the air; 2nd, for the height of the 

 barometer ; 3rd, for temperature ; 4th, for the hygrometrical state 

 of the air ; 5th, for elevation above the ground. 



1 . Telocity of the Air. The greater the speed the more ozone 

 will be apparent, and this seems to be owing more to the increased 

 velocity of the air than to a greater proportion of ozone. 



2. Height of the Barometer. It is found that during the last 

 four years, 



With the barometer at 28 inches the amount of ozone was 5*7 

 29 3*5 



2-0 



t> a 1*3 



0-4 



A law as regards ozone and pres sure is clearly apparent ; but as the 

 barometer falls for wind, the excess at low pressures is no doubt 

 partly due to the increased velocity of the air. There is more ozone 

 with the wind between W.S.W. and S.S.E. than when between 



