280 Proceedings of the Royal Society of Edinburgh. [Sess. 
is of less consequence, yet not to be recalled without a pang, that he had 
a delightful sense of humour, which, coupled with the control he possessed 
over his vast stores of learning, rendered him the most charming of com- 
panions. A school may reckon itself fortunate which has inscribed on 
the roll of its masters the name of so learned, so accomplished, and so good 
a man as was John Sturgeon Mackay.” * 
His retirement from active duty dates from 1904, and as he was com- 
paratively vigorous he looked forward to a period of great usefulness. He 
still spent two months or so of the year on the Continent, and also con- 
tinued his mathematical researches. But latterly his intimate friends 
noticed a diminishing vitality, and although he came back every year 
refreshed and invigorated by the change, it was evident that the heavy 
self-imposed strain of many years was now beginning to tell on him. In 
January of this year, failing eyesight was the first indication that things 
were not right; and as this condition grew steadily worse, it became evident 
that it was symptomatic of very serious weakness, and after lingering for 
a few weeks he passed peacefully away on Wednesday, March 25. Having 
his time so fully taken up with more congenial pursuits, Dr Mackay took 
little or no interest in those affairs that bring men prominently into the 
public eye. To his friends he showed a warm and affectionate disposition ; 
stimulating in his criticism but never censorious, he had the happy faculty 
of saying the right thing and doing the right thing at the right time. 
Anything in the nature of sham, morally or intellectually, was specially 
abhorrent to him, and he very readily detected it. But those who showed 
even in a small degree an inclination to do something more than merely 
“ put in the day ” found in him a staunch friend, willing to do his utmost 
in assisting them in their work, and by his kindly and well-directed 
counsel enabling them to bring their labours to a happy issue. His 
reputation for accurate scholarship extended beyond the confines of his 
own country, and he was frequently appealed to for information by 
savants all over the world. Included among his intimate friends were 
such well-known men in the domain of mathematical science as Neuberg, 
d’Ocagne, Laisant, and Aubert in Belgium and France, Moritz Cantor in 
Germany, and Robert Tucker in our own country. 
The Royal Society did him the honour of electing him to a Fellowship 
in the year 1882 ; and although he admitted the prior claims of the Edin- 
burgh Mathematical Society for his support in the matter of original 
papers, he did useful work as a member of the Council and also as a 
member of its Library Committee. By making him an Honorary Fellow 
* See Edinburgh Academy Chronicle for May of this year. 
