1920-21.] Obituary Notices. 181 
I have touched only on the outstanding problems which Aitken tackled 
and solved; but his many papers on physical subjects show that he 
possessed in a singular degree the power of clear thinking and a real 
intuition for the devising of illustrative experiments. His one aim was to 
get at the truth. He was severely critical of his own experiments, making 
sure at every step that all precautions had been taken against possible 
flaws of adjustment or fallacies of reasoning. He was never satisfied until 
a clear issue was established. Thus for many years he was unable to find 
a convincing explanation of the great increase in the number of dust 
particles at certain times of day at Kingairloch, a small holiday resort 
on Loch Linnhe, to the south of Fort William. Time and again he returned 
to the inquiry ; and at length he was rewarded by the discovery that the 
source of the particles was the foreshore under action of the rays of the sun 
at certain conditions of tide.* 
After the publication of his great paper on Fogs and Clouds, Aitken 
was recognised as one of the original experimenters of his day. In due 
course he received honours and medals from various scientific societies, 
including the Keith and Gunning Prizes from the Royal Society of 
Edinburgh, and a Royal Medal from the Royal Society of London. In 
1899 he received the degree of Doctor of Laws from the University of 
Glasgow. 
Much though his friends desired it of him, Aitken would never accept 
office as president or vice-president in the societies to which he brought 
credit and renown. To the end he remained the same quiet, modest 
investigator, keenly interested in all true scientific progress, and never 
accepting any theory which seemed to him insufficiently supported by 
physical reasoning. Every problem which presented itself was studied in 
his own way and by his own methods, and to him in a peculiar sense we 
might well apply the Horatian line from which the Royal Society of 
London has taken its motto — 
“Nullius addictus jurare in verba magistri.” 
Handicapped through his long life by ill-health, but blessed with a 
competency which made him independent, John Aitken was fortunate in 
being able to cultivate his inborn powers undistracted by official duties. 
Still more fortunate the country which could claim him as one of its 
distinguished sons. 
* See “The Sun as a Fog Producer,” Proc. Roy. Soc. Edin., xxxii, 1912. 
