DISCOVERY 



167 



bent was towards the simplicity and informality of 

 design that is now associated with the drawings of 

 Mr. Heath Robinson. 



***** 

 His interest in science, and especially his desire to 

 measure things, were almost pathological. He had 

 remarkable insight which led him often to foretell 

 what was going to happen in an experiment, or to guess 

 approximately the magnitude of some effect he was 

 about to measure. He was a great man at trying to 

 do everything exactly. One of his greatest discoveries 

 was that of the composition of water. His determina- 

 tion of the mean density of the earth (which Sir Isaac 

 Newton had guessed at between 5 and 6) was less than 

 2 per cent, smaller than the most accurate result of 

 to-day (5-53). He found that there was 20-83 per cent, 

 by volume of oxygen in the air, and the best estimate 

 at the present time is 20-96. In working experiment- 

 ally on the capacity of a chcirged sphere he determined 

 a certain ratio to be 1-57. Years afterwards Lord 

 Kelvin proved that this ratio theoretically must be the 

 half of TT. And the half of - is 1-571. Often he was 

 so anxious to press forward with new experiments that 

 he did not trouble himself to publish a record of those 

 he had finished. As these books abundantly prove, 

 Cavendish had anticipated discoveries which, because 

 he kept a record of them in his notebook instead of 

 pubhshing them, are now attributed to the later 

 workers who rediscovered them. Thus he prepared 

 several chemical compounds, such as arsenic acid, which 

 are attributed to Scheele, and forty-six years before 

 Ohm published his work he discovered the important 

 law in electricity^ which goes by the latter's name. 



***** 



Cavendish paid great attention to electrical resistance 

 — especially to the resistances of solutions. One of the 

 things that puzzled Clerk Maxwell when he went 

 through Cavendish's papers was how the latter 

 was able to measure this. For one cannot measure 

 electrical resistance even at the present day without 

 some kind of a galvanometer, and the galvanometer 

 had not been invented in Cavendish's day. The 

 explanation is simple. Cavendish \vas his own 

 galvanometer. B}- passing the electric current through 

 his own bod\' he estimated its intensity to a nicety by 

 the shock he sustained, and in this way he sized up 

 resistances wonderfully well. 



***** 



It is sometimes argued that a study of the past of 

 any science is a waste of time, since it is difificult enough 

 in all conscience to follow it in its many ramifications 

 to-da}- without saddling oneself with a study of how the 

 facts grew into being. There is much truth in this 

 view, but an occasional dip into the past may and often 



does encourage many a man to set to and do as the 



pioneers have done. It is the same Cambridge which 



gives from time to time to the world the occasional 



writings of her great men of science, of which these 



volumes on Cavendish are an example, which is to-day 



the most considerable centre of discoveries in pure 



science in the world. 



***** 



In the long list of great men whom Cambridge has 



given to the world Cavendish has an honoured place. 



No one wants to affirm he was her greatest son. But 



he was a great man, a natural philosopher of the 



broadest possible t\-pe, who occupied himself in turn 



with every branch of physical science known in his 



time. On each he impressed the marks of his genius 



and the extraordinary penetrative force of his 



intellect. 



***** 



The recent death of Dr. W. Warde Fowler has re- 

 moved one who held a position almost unique in our 

 own day in its felicitous union of the naturalist and 

 the scholar. It seems almost incredible that the man 

 whose ripe scholarship made him the recognised author- 

 ity on the social evolution and the religion of Rome 

 could also find leisure to WTite the only record of 

 English rural life, in Kingham, Old and New, fit to 

 rank with the immortal Natural History of Selborne. 

 ***** 



His latest volume, a collection of some of his papers 

 under the title Roman Essays and Interpretations, 

 which we hope to notice more fully next month, con- 

 tains much characteristic work. For instance, he deals 

 with the habit, common to many Indo-European races, 

 of associating the oak \\ith Jupiter, the thunder-god. 

 He shows that the sanctity of the oak is probably 

 connected with the strange fact that this tree is more 

 often struck by lightning than any other. If the 

 frequency with which beech trees are struck be repre- 

 sented as unity, the figure for oaks is sixty. The 

 human interest, the scholarly criticism, and the sincere 

 love of nature which these papers show are typical 

 of his many-sided personality. Dr. Warde Fowler 

 will be regretted by a far wider circle than his own 

 University of Oxford. 



***** 



Elsewhere in this issue is printed a letter from Sir 

 Arthur Conan Doyle bearing on my editorial remarks 

 of last month. The question at issue is the existence 

 of fairies. It may be said here that an argument on an 

 important subject like this one cannot be conducted 

 adequately in the pages of a popular magazine. It is 

 a problem for a learned society— for authority, not 

 private judgment. Only in such a society can a fair, 

 an unprejudiced, and an impersonal opinion on the 

 matter be arrived at. 



