ON THE AMOUNT AND DISTRIBUTION OP INCOME. 199 



we find still only the statement in a footnote that the 9d. rate was 

 allowed to approximately three-quarters of a million persons annually. 

 It is greatly to be desired that the Commissioners should publish 

 detailed information showing the total number of persons who pay the 

 lower rate, the numbers in relation to the amount of earned income, 

 and the numbers in relation to the amount of income whether earned 

 or unearned. 



Gaseous Explosions. — Third Report of the Committee, consisting of 

 Sir W. H. Preece (Chairman), Mr. Dugald Clerk and Professor 

 Bertram Hopkinson (Joint Secretaries), Professors Bone, 

 Burstall, Callendar, Coker, Dalby, and Dixon, Dr. Glaze- 

 brook, Professors Petavel, Smithells, and Watson, Dr. Harker, 

 Lieut.-Colonel Holden, Captain Sankey, Mr. D. L. Chapman, and 

 Mr. H. E. Wimperis, 1 appointed for the Investigation of Gaseous 

 Explosions, with special reference to Temperature. • 



APPENDIX PAGR 



A. Radiation from Flames 214 



B. On Radiation in a Gaseous Explosion 221 



C. Abstracts from papers relating to Siemens' Furnaces 225 



Six meetings of the Committee have been held, one each at the Univer- 

 sities of Leeds, Manchester, and Cambridge, one at the Imperial College 

 of Science and Technology, and two at 57 Lincoln's Inn Fields, by 

 the kindness of Mr. Dugald Clerk. In accordance with previous prac- 

 tice, notes dealing with their current work have been presented for 

 discussion by members of the Committee, as follows : — 



No. 14. Dissociation A. Smithells and W. A. Bone. 



No. 15. Ignition Temperatures of Gases . . H. B. Dixon. 



No. 16. Modern Theories of Gases . . . Sir W. H. Preece. 



No. 17. Radiation from Flames . . . . H. L. Callendar. 



No. 18. Radiation in a Gaseous Explosion . B. Hopkinson. 



During the Session 1909-10 the experimental work by members of 

 the Committee, to which allusion was made in the Second Eeport 

 (1909), has been continued. Mr. Dugald Clerk's measurements of the 

 volumetric heats of air and C0 2 at ordinary temperatures by the method 

 of adiabatic compression have yielded results in close accordance with 

 those obtained by Swann. The method of division of heat-loss 

 employed by Mr. Clerk in reducing the results was the same as that 

 which he used in his original high temperature experiments. The 

 correctness of the results obtained at the lower temperatures by this 

 method goes far to justify its application to the compression and expan- 

 sion of highly -heated gas. An account of these experiments will shortly 

 be published, and will be quickly followed, it is hoped, by an account 

 of further work on the compression of flame and heated gases on which 

 Mr. Clerk is already engaged. Professor Hopkinson has published a 



1 Mr. Wimperis joined the Committee after the completion of the Report. 



