646 
Mr. W. A. Fraser (Edinburgh), Mr. S. L. Rothery 
(Calexico, U.S.A.), Mr. Mark Randall (Johannesburg), 
and Mr. D, E. Lloyd-Davies (Cape Town) ; an Indian 
premium to Mr. D. H. Remfrey (Calcutta) ; a Manby 
premium to Mr. F. M. G. Du-Plat-Taylor (London) ; 
and a Crampton prize to Mr. F. W. Jameson (Kim- 
berley). 

AN appreciation of the scientific work and dis- 
coveries by Sir James Dewar was broadcasted by 
_ Prof. J. A. Fleming on May 4 from the London station 
2 LO. Prof. Fleming first referred to’ Sir James 
Dewar’s work on the liquefaction of air, oxygen, and 
hydrogen, and the invention of the silvered vacuum 
vessel for storing these liquids. Closely related with 
this work was the discovery of the use of charcoal 
cooled in liquid air for the production of high vacua. 
Sir James Dewar also made important discoveries in 
spectroscopy and in connexion with the production 
of physiological electric currents by the action of 
light. His work in chemistry contributed to the 
invention of cordite, while soap films and _ their 
behaviour in dust-free air occupied his attention until 
the last day of his working life. Sir James Dewar’s 
investigations were undertaken in the first instance 
purely out of a disinterested desire to increase 
scientific knowledge, but the results have in nearly 
every case produced numerous beneficial and practical 
applications. 
Ar the annual meeting of the members of the Royal 
Institution held on May 1, the following officers were 
NATURE 

elected : President, The Duke of Northumberland ; | 
- [May 12, 1923 
Treasurer, Sir James Crichton-Browne ; Secretary, Sir 
Arthur Keith; Managers, Mr. S. G. Brown, Dr. J. M. — 
' Bruce, Sir Dugald Clerk, Prof. J. A. Fleming, Sir Richard 
Glazebrook, Earl Iveagh, Sir Alexander C. Mackenzie, 
Mr, Robert Mond, Sir Edward Pellock, Prof. A. W. 
Porter, Lord Rothschild, Sir David Salomons, Mr. 
W. Stone, Sir Alfred Yarrow, The Right Hon. Lord 
Justice Younger; Visitors, Sir Harry Baldwin, Prof. 
William A. Bone, Mr. A. Carpmael, Dr. E. Clarke, 
Mr. E. Dent, Dr. T. W. Dewar, Mr. G. H. Griffin, Mr. 
W. E. Lawson Johnston, Col. F. K. McClean, Sir 
Malcolm Morris, Dr. W. Rushton Parker, Mr. W. 
Peacock, Major C. E. S. Phillips, Mr. H. M. Ross, and 
Mr. S. Skinner. Sir J. J. Thomson has been elected 
honorary professor of natural philosophy, and Sir 
Ernest Rutherford professor of natural philosophy. 
The Duke of Northumberland has nominated the 
following gentlemen as vice-presidents for the ensuing 
year: Dr. Mitchell Bruce, Lord Iveagh, Sir Edward 
Pollock, Lord Rothschild, Sir Alfred Yarrow, The 
Right Hon. Lord Justice Younger, Sir James Crichton- 
Browne (Treasurer), and Sir Arthur Keith (Secretary). 
A CATALOGUE (No. 259) of books in all branches of 
chemical science and technology, including the textile 
industries and agriculture, has just been issued by 
Mr. W. Bryce, 54 Lothian Street, Edinburgh. It 
should be very useful for reference. The same book- 
seller also issues a short list of second-hand books in 
technology, the classics and general literature, surplus 
government stock, which are offered at greatly reduced 
prices. : 

Our Astronomical Column, 
THE APRIL METEOR SHOWER.—Mr. W. F. Denning 
writes: ‘‘ This event occurred on the nights of April 
21-23. The weather, however, was not very favour- 
able on the night of expected maximum, April 21, 
and few meteors could be seen owing to clouds. The 
special display of Lyrids supplied nearly half the total 
number of meteors observed on the three nights, 
and the radiant point was in the usual position at 
about 272° + 33°. 
“Tt sometimes happens that when the Lyrids are 
not very abundant, meteors generally are very scarce, 
and this appears to have been the case on the recent 
occasion, the hourly rate of apparition being only 3. 
“There are a considerable number of radiant points 
in activity at this period of the year, but the great 
majority of them are extremely feeble, and an 

. observer must watch the sky for a long period before 
they may be recognised. Two meteors seen on 
April 20 last were each recorded at two stations and 
the paths indicate radiants at 271°+35° and 310° 
Oo” 
Brio}? ia 
TEMPERATURE AND DENSITY OF THE UPPER ATMO- 
SPHERE DEDUCED FROM Merrors.—Prof. F. A. 
Lindemann and Mr. C. M. Dobson contribute a paper 
on this subject to Proc. Roy. Soc. (Series A, vol. 102, 
No. A 717). They deal with the large number of 
doubly observed meteors discussed by Mr. Denning, 
and give reasoning which leads to the conclusion that 

during most, if not all, of the meteor’s visible track, 
the molecules of air impinge on a layer of compressed 
NO. 2793, VOL. 111] 
air in front of the meteor. Evaporation goes on from 
the surface of the meteor, and in general the meteor 
is wholly consumed long before reaching the ground. 
Long-enduring trains are explained as the slow 
recombination of ions separated by the energy of the 
meteor. The meteors are shown to be very small 
particles. One as bright as a star of the first magni- 
tude would be 1 mm. in diameter. One as bright as 
the moon would be 2°5 cm. in diameter (mass 62 gm.). 
Discussion of the observed phenomena on these lines 
leads to determinations of the temperature and density 
of the air at different heights. It is concluded that 
the isothermal layer, already discovered by ballon 
sondes to extend to a height of 25 km., goes on up to 
50 km.; but that above that height the temperature 
again rises to 280° or 300° abs. The density of the air 
at 100 km. (about the lower auroral limit) comes out 
100 times that previously assumed ; it is suggested 
that it may not be hopeless to reproduce the auroral 
spectrum in the laboratory, if the corresponding 
density is ro-§ instead of ro7!. j 
It is suggested in explanation of the high tempera- 
ture of the upper air that it is largely composed of 
ozone, which is heated by the infra-red radiations 
from the earth. 
Prof. Lindemann describes in Mon. Not. R.A.S. ~ 
for January a method which he is using of photo- 
graphing meteors simultaneously at stations some 
distance apart, so as to get their height very accurately 
in order to apply a more rigorous check to his con- 
clusions, : . 
