>38 



NATURE 



[November 27, 1919 



physical research, for which he received a stimu- 

 lus as a student under Sir William Thomson 

 (Lord Kelvin) in Glasgow University. He lived 

 a retired life in Falkirk in a house which was 

 largely fitted up as a laboratory, whence he would 

 emerge from time to time to communicate some 

 novel experiment or observation to the Royal 

 Society of Edinburgh. Dr. Aitken frequently 

 visited the Continent, partly for his health's sake, 

 and never failed to utilise his opportunities in 

 studying at first hand the varied meteorological 

 conditions of our globe. He published scientific 

 papers in the Philosophical Magazine and through 

 the publications of the Royal Societies of London 

 and Edinburgh, but it was mainly through the 

 latter society that his important investigations 

 were laid before the scientific world. 



In his classical memoir on dust, fog, and clouds 

 (1880) Dr. .Aitken broke entirely new ground, 

 and by his later paper on dew (1885) he consoli- 

 dated his reputation as a natural philosopher of 

 the first rank. Those who were privileged to see 

 his demonstrations before the Royal Society of 

 Edinburgh in 1880 can never forget the effective 

 simplicity of his apparatus and the clearness of 

 the argument by which he established the great 

 truth that invisible dust particles are the nuclei 

 on which water vapour condenses to form mist/ 

 fog, and cloud in all their infinite variety. By 

 successive slight exhaustions of saturated air in 

 a glass receiver, and by infiltration through cotton- 

 wool of ordinary air from the outside, he gradu- 

 ally cleared it of dust particles ; and when this 

 purification had been effected, expansion with 

 cooling of the enclosed air was, in general, un- 

 accompanied "bv the formation of cloudy condensa- 

 tion. He noted, however, in these early experi- 

 ments, that after the air had been thus purified 

 of dust particles, a more rapid and somewhat 

 greater expansion was sometimes accompanied bv 

 cloudy condensation. The explanation of this was 

 afterwards given by Mr. C. T. R. Wilson, who 

 showed that in dustless saturated air suddenly 

 expanded electric ions acted as nuclei on which 

 drops of water were deposited. This ionic con- 

 densation requires a distinctly greater diminution 

 of pressure than is needed to effect the doudy 

 condensation in ordinary unfiltered air, and in his 

 last paper on the subject of cloudy condensation 

 (Proceedings R.S.E., 1917) Dr. /Vitken gave many 

 experiment.'il illustrations of his belief that under 

 ordinary atmospheric conditions the nuclei on 

 which fog, mists, and clouds form are funda- 

 mentally the dust particles, although the effect 

 may be occasionally intensified by the presence of 

 ions. 



Dr. Aitken followed up his main investigations 

 in many ingenious ways, inventing, for example, 

 an instrument for counting the number of particles 

 in a given specimen of air, and applying it to the 

 study of the conditions under which the number 

 of dust particles varied according to locality, wind, 

 barometric pressure, or time of day. In all these 

 discussions he displayed unusual powers of accu- 

 rate observation, great skill in devising crucial 

 NO. 2613, VOL. 104] 



experiments, and singular gifts in inteqjreting 

 natural phenomena. His researches led him into 

 questions of colour in cloud, .sky, and sea, and 

 into the dynamical laws of cyclones and anti- 

 cyclones. In this last branch of meteorology he 

 found himself at variance with other leading 

 meteorologists. Dr. Aitken was elected a fellow 

 of the Royal Society of Edinburgh in 1875, and 

 of the Royal Society of London in i88g. By the 

 former he was awarded the Keith medal and 

 prize (1886), and the Gunning jubilee prize (1895), 

 and by the latter a Royal medal in 1917. In 1899 

 he received the degree of Doctor of Laws from 

 Glasgow University. He was a lovable person- 

 ality and of great modesty of disposition. Much 

 though his many friends desired it, he would never 

 allow himself to be nominated for high office in 

 the Royal Society of Edinburgh. This, he main- 

 tained, was not his forte. He was a humble 

 student of natural phenomena, and his one desire 

 was to elucidate the workings of Nature in her 

 everyday moods. C. G. K. 



NOTES. 



The Electricity (Supply) Bill, which passed the'rei)ort 

 stage in the House of Commons on Tuesday, is a 

 laudable attempt by the Government at constructive 

 economy. In almost every business, combination and 

 standardisation lead to great economies, and this 

 applies in a very special manner to the supply of elec- 

 tricity. .\n attempt was made on Monday to prove 

 that the Bill in its present form was a breach of the 

 agreement made in the Act of 1888 whereby a term 

 of forty-two years was granted to the companies to 

 carry on their supply without Government mterfer- 

 ence. This is perhaps technically right, but the com- 

 panies have no real grievance. The Bill leaves tlieir 

 distributing business undisturbed, and guarantees to 

 supply them with electricity as cheaoiv as thev could 

 generate it for themselves. Lord Mouhon and others 

 have laid great stress on the economy, from the point 

 of view of the conservation of coal, of using gas for 

 heating instead of electricity. Many electrical en- 

 gineers will agree with this view. But although elec- 

 trical supply companies will provide energy for healing 

 — generally at prohibitive rates — when they are specially 

 asked, they regard the heating load as of minor 

 importance. Electrical heating forms onlv one of the 

 manifold uses of electricity. Every engineer knows 

 that cheap power is essential to many of our most 

 important industries. Our supremacy as a commercial 

 nation depends on a plentiful supply being available. 

 .'V cheap and abundant supply would soon effect an 

 industrial revolution, and be a special boon to the 

 manual workers. .\nother objection that has been 

 urged against the Bill is the danger of strikes. If a 

 national system of supply were adopted, and if the 

 electric workers went on strike, the work of the nation 

 could be held up at any moment and the nation forced 

 to grant the demands of the workers, however un- 

 reasonable they were. The experience gained bv the 

 workers, however, durins? the recent railwav strike 

 ought to discourage similar action against the com- 

 munity in the future. 



Under a Bill introduced by the Government last 

 week, power is given to the Board of Trade to safe- 

 guard "key" industries in this country bv prohibiting 

 the importation of certain articles. Of chief scientific 

 interest among these are analytical reagents, photo- 



