CORRESPONDING SOCIETIES. 439 



smoke-laden air. The difficulty was to test this view. Recently a wind screen 

 such as Dr Owens described, had been put up in Rochdale in the hope that it 

 would eive some indications as to the direction from which most of the pollution 

 came A more satisfactory plan would be to have a chain of gauges m a 

 direction east and west, if authorities could be induced to put them up. More 

 o-auges, simple and easily recording, were much needed all over the country 

 ff any improvement was to be effected. No one local authority can do much 

 alone, and to have concerted action pressure must be brought to bear from the 



Government. . , ■ i .• • ^ x- 



He also drew attention to the fact that since coal- rationing came inU> force 

 there had been a marked reduction in the amount of tar in the atmospheric 

 deposit of Rochdale, which showed that, with a more careful consumption and 

 combustion of coal, a great improvement in the state of the atmosphere might be 



l)rought about. ,, ■ l, ^ i. 



Professor W. W. Haldane Gee said that Bournemouth in beptember was 

 the wrong place to study air-pollution, which appeared to be a minimum. In 

 laro-e towns such as Manchester air-pollution was a very serious problem. He 

 suggested that the time was opportune for the Advisory Committee on Atmo- 

 spheric Pollution to turn its attention to a study of the methods for preventing 

 the contamination of the atmosphere. At Manchester, the Advisory Board 

 on Air Pollution of the City Council is directing researches relating to domestic 

 heating, with a view to lessening air-pollution and effecting fuel economy. 



With reference to the study of pollution, assistance would be given by the 

 increase of the number of gauges, which might at the same time be employed 

 to measure rainfall. 



Mrs. Ellis Chadwick pointed out that air-pollution of the atmosphere is 

 of the utmost importance to women, as they have the task of getting rid of 

 the dirt which finds its way into the house. It also prevents the housekeepers 

 from having open windows, as what should be fresh air is often dirty air. 

 Window curtains and clothing suffer much more in some districts than others, 

 on account of the uncleanliness of the atmosphere, and it is very necessary 

 that we should have clean air to breathe from the question of health. 



Dr. Owens replied as follows : Professor Lea raised the question whether 

 polluted air was unhealthy. It has been shown that the incidence of fogs in 

 cities has a great effect on the death-rate from respiratory diseases, and he 

 thought that there need be no question as to the injurious effects of breathing 

 impure air. Both Professor Lea and Professor Gee spoke of the importance 

 of a policy of prevention, and suggested directions in which to look for improve- 

 ment. He thought, however, that it would be a mistake to suspend ,the 

 measurement of impurity in the air, as, whatever steps were taken in the 

 way of prevention, we should require some means of ascertaining whether they 

 were successful or not. Dr. Ashworth asked how the straight line drawn 

 through the curve of rainfall and soluble deposit was fixed. It wns drawn bv 

 eye, as it was recognised that it could only be an approximation; in fact, it 

 must be some form of curve which approaches a limiting value for high rainfalls, 

 and not strictly speaking a straight line. Professor Gee's suggestion of a com- 

 bined rain and deposit gauge seemed to be a very good one, and should be 

 considered carefully. 



At the second meeting of the Conference, held on Friday, September 12, 

 the President again took the chair, and Mr. M. de Carle S. Salter (Superinten- 

 dent of the British Rainfall Organisation) read the following Paper : — 



The Exposure of Rain Gauges. By M. de Carle S. Salter 

 (Superivtendevf, British Bainfall Organization). 



The measurement of rain is commonly described as the most simple of all 

 meteorological observations, and from the point of view of the actual operation 

 t'^e statement is no doubt justified. It is fortunate that this is so, for the 

 phenomenon of rain, in regard to its distribution in space and time, is in 

 some respects so capricious and irregular that in order to study it successfully, 

 observations are required from a far greater number of points than suffice 



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