September 22, 192 1] 



NATURE 



127 



parallaxes from double stars for which the relative 

 motion is known. Again, although the linear 

 speed differs considerably from one star to 

 another, the proper motions of stars can be con- 

 sidered as an index to the distance — a much better 

 index than the apparent brightness. 



In these and other indirect ways our knowledge 

 of stellar distances is being rapidly advanced. It 

 must be remembered that it is all ultimatelv based 



on measured or trigonometric parallaxes. The 

 larger trigonometric parallaxes can be applied 

 directly to the individual stars concerned, but for 

 the smaller parallaxes the discussions must be of 

 a statistical nature, as the errors of observation are 

 too great. The indirect methods can, however, 

 be pushed to stars at very great distances if only 

 they appear bright enough for the necessary 

 observations to be made. 



Obituary. 



John Robert Pannell. 



JOHN ROBERT PAXXELL, who was killed in 

 the disaster to the airship R38 while making- 

 observations on behalf of the Xational Physical 

 Laboratory, was the only surviving child of Mr. 

 and Mrs. Pannell, of Xutley. He was b.orn in 

 1885. A delicate childhood, which none would 

 have suspected from his adult physique, interfered 

 greatly with his education, but after courses at the 

 Northampton Institute and some engineering 

 works experience he joined the Xational Physical 

 Laboratory in 1906 as a student assistant. 



His best-known work is that carried out in con- 

 junction with Mr, Stanton on dynamical similarity 

 in the flow of liquids in pipes, which has become 

 classical as the most complete demonstration of 

 that principle in its important applications to 

 hydrodynamics. \\'ith Mr. Stanton he also in- 

 vestigated with great elaboration the strength of 

 welded joints ; but most of his work is to be found 

 in reports to the Advisory Committee for Aero- 

 nautics covering almost the whole range of ex- 

 perimental inquiry in aerodynamics. When prob- 

 lems of airship construction became prominent in 

 1916 he took part in most of the model measure- 

 ments on resistance and the efficiency of controls ; 

 and when, again, after the war, it became pos- 

 sible to compare the results of model and full- 

 scale tests, Pannell took charge of the latter and 

 was constantly making observations on airships in ; 

 flight. ' 



In a science so little amenable to general theory 

 the ability to make long and tedious series of 

 routine measurements without allowing familiaritv 



to breed carelessness is of special importance- 

 This ability Pannell possessed in the highest 

 degree. He had that genial serenity and evenness, 

 of temper often associated with one of his gigantic 

 stature ; neither the perversity of apparatus nor 

 the impatience of petulant colleagues could make 

 him relax for a moment the precautions that are 

 the first necessity of such work. If the humaa 

 tragedy of the R38 is partially compensated by a 

 gain to science, that gain will be largely due to 

 merits in Pannell's work which are too often 

 eclipsed by more brilliant but not more useful 

 achievements. 



In private life the most lovable of men, he 

 radiated kindness and good temper. He was of 

 tireless physical energy, and his war-time leisure,, 

 devoted to a small farm, shamed the full-time 

 occupation of many men. He leaves a widow, 

 the true partner of all his labours, with whom all 

 will feel sympathy in the exact measure of their 

 acquaintance. X. R. C. 



W^ learn, with regret, of the death on Septem- 

 ber 10, from drowning near Ottawa, of Mr. 

 F. W. L. Sladen, author of "The Humble-bee: 

 Its Life-history and How to Domesticate It." 

 Mr. Sladen was forty-five years of age. 



The death of Mr. John Pearce Roe took place 

 on September 2. Mr. Roe was born in 1852, and 

 was the chairman and managing director of Rope- 

 ways, Ltd., of London. He carried out a large 

 amount of work in connection with the transport- 

 ing of materials by means of aerial ropeways. 



Not 



The Chemical Age announces that Sir William Pope I 

 has been elected an honorary fellow of the Canadian j 

 Institute of Chemistry. 



It is announced that the annual meeting for 1922 

 of the British Medical Association will be held at 

 Glasgow on July 21-29. The authorities of Glasgow 

 University have given the association permission to 

 use the University buildings, and offers of assistance 

 should be addressed to Dr. G. A. Allen and Dr. J. 

 Russel at the University. 



We learn from the Lancet of September 17 that 

 the Health Committee of the League of Nations is 

 constituted as follows : — Dr. L^on Bernard, professor 

 NO. ^708, VOL. 108] 



es. 



of hygiene in the University of Paris ; Dr. G. S^ 

 Buchanan, senior medical officer of the British 

 Ministry of Health; Prof. .A. Calmette, director of 

 the Pasteur Institute in Paris ; Dr. Carozzi, medical 

 director of the International Labour Bureau ; Dr. 

 Henri Carriere, director -general of the Swiss Public 

 Health Service ; Sir Havelock Charles, president of 

 the Medical Board for India; Dr. Chodzko, Minister 

 of Health for Poland ; Dr. Lutrario, director-generaf 

 of the Italian Public Health Service; Dr. Th. Madsen, 

 director of the State Institute of Serotherapy at 

 Copenhagen ; Prof. Miyajima, of the Kitasato Insti- 

 tute for Infectious Diseases, Tokyo; Dr. Pulido, pre- 

 sident of the Spanish Royal Council of Public Health r 



