September 9, 1922] 



NA TURE 



367 



The First Messel 



T~)R. RUDOLPH MESSEL came to England in 

 ^ 1870 and died here in 1920. During the fifty 

 years of his residence in this country he was engaged 

 in the manufacture of sulphuric acid ; he was a 

 chemist of considerable repute, a fellow of the Royal 

 Society, an accomplished and kindly man ; by his 

 will he left the whole of his fortune to the Royal 

 Society and the Society of Chemical Industry. The 

 council of the latter Society decided to set aside a 

 small part of the legacy to found a series of Messel 

 Memorial Lectures to be delivered by eminent chemists, 

 each of whom is to receive a Messel medal. The first 

 of such lectures was delivered in Glasgow last July 

 by Prof. H. E. Armstrong, who was for very many 

 years an intimate friend of Dr. Messel. The lecture 

 is now published in the issue of the Journal of the 

 Society of Chemical Industry for August 15. 



The subject of the lecture is " Chemical Change and 

 Catalysis," but Prof. Armstrong contrives to make 

 sundry alarums and excursions into adjacent terri- 

 tories. There is a good and sympathetic account of 

 the life and work of Messel, some amusing chaff of 

 Ostwald and his school of ionic chemists, of Bancroft 

 and his satellites, of colloid chemists and most other 

 varieties of chemists, and an important contribution 

 to our conceptions of the processes involved in 

 chemical change. The lecture is important not so 

 much because of the new matter in it, but because it 

 puts the problem in an arresting manner and compels 

 those readers who have any power of thought to cry 

 a halt for a moment and consider first what the 

 lecturer means, and then what the reader really 

 thinks on this subject, and whether a good deal of 

 what he has been in the habit of thinking is sound or 

 not. Prof. Armstrong has long scoffed at text-books 

 and has very successfully practised a method of 

 teaching, the vital principle of which is to tell very 



Memorial Lecture. 



little and make the pupil do a good deal of thinking 

 and investigating. He continues to practise his 

 method, if this lecture is any criterion of his present 

 habits. The view he outlines is that no chemical 

 change takes place except in the presence of an electro- 

 lyte, which he calls the " determinant " ; unless the 

 substances concerned are in an electric circuit chemical 

 activity is suspended. The work of Prof. H. B. Baker 

 on the inactivity of perfectly dry substances is referred 

 to several times. Electrolytic conductivity is dis- 

 cussed and the electrolysis of water ; according to 

 the lecturer this takes place in stages, the first stage 

 being the formation of hydrogen peroxide ; this 

 unstable compound plays an important part in the 

 association views of Prof. Armstrong : it is the first 

 stage in the oxidation of hydrogen. The combustion 

 of carbon monoxide, the oxidation of xanthin and hypo- 

 xanthin arediscussed, and there is some accountof cata- 

 lysis, the action of enzymes, and the nature of acids. 



The determination of Prof. Armstrong or perhaps 

 his catalytic nature compels the mind of the reader 

 to execute a sort of Brownian movement. He is 

 driven from Gowland Hopkins to Meredith, from 

 hydroxylation to Hudibras, from colloids to Lewis 

 Carroll. And when he thinks, good, easy man, full 

 surely the argument is ripening, he is switched off 

 to a quotation from Erasmus Darwin or some new 

 paradox about the basic properties of sulphuric acid, 

 in a manner which those who are familiar with Prof. 

 Armstrong's style will easily imagine, although they 

 cannot — one scarcely knows whether to say fortu- 

 nately or unfortunately — imitate it. 



No one will begin this lecture without finishing it. 

 No one will fail to be interested and amused ; no one 

 will come to the end without a stimulus to thought, 

 a renewed curiosity as to chemical change, a new 

 scepticism, and fresh ideas. 



Stellar Radiation 



"P)R. W. W. COBLENTZ 1 is developing the applica- 

 -*-^ tion of the thermocouple to the study of stellar 

 radiation, and is deriving results of considerable 

 interest and value, especially so far as red stars and 

 red variables are concerned. The instrument he uses 

 is not so sensitive as the photo-electric cell which is 

 doing such delicate work in the hands of Guthnick, 

 Stebbins, and others, but it lends itself more readily 

 to the investigation of radiation in the longer wave- 

 lengths. 



Most workers engaged on spectrophotometric 

 measures of the stars have concentrated on the visible 

 spectrum. Dr. Coblentz uses various transmission 

 screens which allow only radiation over fairly 

 narrow regions of the spectrum to pass through to the 

 thermocouple. He thus obtains the spectral energy 

 distribution of the stars, and derives stellar tempera- 

 tures agreeing fairly closely with the values obtained 

 at Potsdam by Wilsing, Schemer, and Munch. The 

 chief interest lies in the extension to their work that 

 he makes by using a water absorption cell, which is 

 transparent for radiation between 0-3 ^ and 1-4/4 in 

 the infra-red, and does not absorb much radiation less 

 than 0-5 n in wave-length. When the transmission 

 through a layer of 1 cm. of water is only a small 

 fraction of the incident radiation as in the case of 

 a-Orionis and a-Scorpii, then Dr. Coblentz rightly 

 concludes that the total radiation from these stars 

 is far higher than is suggested by their visual magni- 

 tudes. It appears that we are faced with the fact 



1 Scientific Papers of the Bureau of Standards, No. 43S. " Tests of 

 Stellar Radiometers and Measurements of the Energy Distribution in the 

 Spectra of 16 Stars." Washington, 10 cents. 



NO. 2758, VOL. I IOJ 



in the Infra-red. 



that photo-visual methods can give us trustworthy 

 magnitudes of stars only for a limited range, and that 

 certain stars, especially nova, radiate with much 

 greater intensity in the extreme ultra-violet than we 

 are allowed by our atmosphere to measure, while 

 others — the red stars and invisible dark stars — 

 radiate with great intensity in the infra-red. 



Even within the range where visual methods have 

 prevailed, Dr. Coblentz shows that the failure to take 

 into account the infra-red radiation has given much 

 too small a value for the luminosity, or intensity of 

 radiation, of the giant red stars, this may account 

 for the puzzling "fact which Prof. Russell recently 

 proclaimed, that giant stars of all spectral classes were 

 of about the same absolute magnitude. Dr. Coblentz's 

 evidence is that this is not the case, but that the giant 

 red stars are radiating far more energy than are the 

 giant blue stars of the same visual absolute magnitude. 



A further point of interest arises from the close 

 relation between a star's spectrum and the transmis- 

 sion of its radiation through a water-screen. When 

 more radiation is lost in passing through the screen 

 than is normal with the spectral class to which a star 

 belongs, this has been traced to the presence of a 

 dark companion to the star which makes its presence 

 known in vet a new way by the action of its hitherto 

 unnoticed "infra-red radiation. It is to be hoped that 

 the method mav be made more sensitive, or that some 

 more sensitive measure of infra-red radiation may be 

 developed which will enable the astronomer of the 

 next century to measure the radiation from the dark 

 nebula? and — it is not an impossible thought— to 

 plot the dark stars on the next Carte du del. 



