INVESTIGATION OF THE UPPER ATMOSPHERE. 257 



Mr. Whipple has recently organised observations of the time of passage of air waves 

 from gunfire. His initial success, in January 1926, was in timing the passage of 

 audible sound from Shoeburyness to Grantham. Recently, with the assistance of 

 the British Broadcasting Corporation, the times of firing a gun at Shoeburyness 

 have been broadcast, and the assistance of the public in listening has been invoked. 

 It appears that the occasions when sound can be heard at very great distances are 

 rare and exceptional ; observations with hot wire microphones, however, have been 

 very successful. At Birmingham University good results have been obtained at 

 each of three trials. Correlation with meteorological data promises to prove a 

 valuable line of research. 



The counting of the dust particles by the Owens dust counter, which was one 

 of the original suggestions of the Committee to the British National Committee, has 

 been warmly taken up in the United States and observations have been made regularly 

 in Australia for the Bureau of Meteorology by Dr. E. Kidson, who has now become 

 Director of the Meteorological Service of New Zealand. In Mr. Hunt's report to the 

 Meteorological Section Dr. Kidson raises the question of the relation of the dust count 

 in the Owens Counter with that in the Aitken Counter, a question of interest and 

 importance. In the United States attention was turned to the dust counts at different 

 levels of the atmosphere as observed in balloons or aeroplanes ; but the subject has 

 not been pursued since the death of Mr. C. Le Roy Meisinger while engaged upon that 

 inquiry. No other country has yet contributed information on that subject. 



The Interest of Universities and Science Departments of Schools. 



It is interesting to note that some of these researches owe much to the Universities. 

 Dr. Dobson's work on ozone was carried out at Oxford, and his collaborators have 

 been students in that University. Yeoman service has been rendered to Mr. Whipple's 

 investigation of the audibility of gunfire by the Physical Departments in the Uni- 

 versities of Birmingham and Bristol, and in University College, Southampton. 



The Committee is of opinion that there is still an opening for co-operation on the 

 part of Universities and the Science Departments of Schools for those aspects of the 

 investigation of the upper air which can be worked by the simultaneous action on 

 selected occasions of moderately instructed observers over the country generally, as 

 distinguished from the repetition of regular observations by the trained staff of the 

 official establishments. As an example of an investigation which might be bene- 

 fited by such co-operation may be cited the investigation of the structure of a 

 typical cyclonic depression by a number of simultaneous soundings with registering 

 balloons, supplemented by a much larger number of what may be called post card 

 balloons. 



Such an investigation, however, requires the special attention of some such body 

 as a Committee of the British Association to prepare a detailed programme, arrange 

 for the supply of necessary apparatus and materials, issue instructions and give notice 

 of the selected occasion which would naturally be so chosen as to fit in with the 

 international organisation. 



If a suitable scheme could be drawn up in conjunction with the Association of 

 Science Teachers the B.B.C. would probably not refuse its invaluable help in securing 

 volunteers and notifying a suitable occasion. 



The Committee has considered the possibility of initiating investigations of this 

 kind. 



They have in mind a project of obtaining foreshortened stereoscopic photo- 

 graphs of clouds by which valuable information might be obtained as to the position 

 and dynamical condition of lenticular clouds in relation to their environment. The 

 idea of obtaining foreshortened photographs of clouds was used with success many 

 years ago by Mr. J. Tennant, who has sought various opportunities of developing it. 

 It could easily be brought into general use as a co-operative exercise. 



It is also thought that arrangement could be made without great expense for the 

 supply of apparatus and material which would enable those in charge of a school 

 laboratory to fill a balloon, and that schools thus equipped would be willing to co- 

 operate in an inquiry into the structure of the upper air on some occasions which 

 might be notified by broadcasting. Mr. L. F. Richardson has kindly given the Com- 

 mittee assistance in the matter and devised an effective means of supplying apparatus 

 for filling balloons at the cost of two shdlings each for the apparatus and a shilling 

 for each turn. A note by Mr. Richardson is appended to this report. The Committee 

 is of opinion that a co-operative investigation of that kind would afford evidence of 

 the structure of the atmosphere in ' dirty weather,' which is much needed in order 



1927 S 



