xx vi Proceedings of Royal Society of Edinburgh. 
especially in America, in which accuracy is a sine qua non — shows 
how true his instinct was, and how correct his views were regard- 
ing the designing and construction of tools. Even in small matters 
his love of accuracy crops up, for he had his drawing-pens fitted 
with screws having divisions on their milled heads representing 
lines of different breadths, to which the pen could at once he set. 
He was a beautiful draughtsman, and was never at a loss, with pen 
or pencil, in making clear even complicated pieces of mechanism. 
The man of science goes to nature and asks pointed questions. To 
these, up to a certain limit, he gets answers of precision ; but philo- 
sophers are not inclined to stop there, and they go on asking ques- 
tions to which they can get no possible solution. Why ? is ever on 
their lips ; and when there is no answer, or one which is unsatisfac- 
tory, belief in the existence of a Supreme Euler and Governor is apt 
to vanish, and Doubt sits down in the empty chair from which 
Faith has been driven. Sang was not one of that class. He never 
obtruded his opinions on such matters, but his belief in a Supreme 
Euler was strong and unequivocal. If he alluded to the subject it 
was always in the most reverential spirit. In an address he gave 
at the Jubilee of the Society of Arts in 1867, he said : — “ The 
exquisitely-carved shell of the minutest diatom reveals arrange- 
ments and contrivances infinitely beyond all that man has done or 
ever will do ; and we place our hands upon our mouths, our faces 
in the dust, in the presence of a wisdom that we cannot begin to 
comprehend, of a goodness that overwhelms us.” In a paper he 
read in 1884 he concluded by saying : — “ Of the untiring goodness, 
the unfathomable wisdom evident in all that passes around us, even 
in the mysterious complexity of human life, let us recall what has 
been said, — £ He rewardeth the searcher and the keeper of His 
laws.’ ” On a large telescope wdiich he mounted himself for the 
Wray lens he got from the Institution of Civd Engineers, he in- 
scribed that precious motto in golden characters in Turkish and 
English; and when, in times of depression, from which few are 
exempt, he felt that his labours were not rewarded as they should 
have been, we can fancy him getting comfort and inspiration from 
such a motto. But he was a busy man, and the busy man is 
generally a happy man. Eeason rather than memory was what he 
valued and appealed to in connection with his pupils. Parrot-work 
