xx Proceedings of Royal Society of Edinburgh. 
the next four sessions he studied Natural Philosophy under Pro- 
fessor Leslie, two as a regular student and two as a holder of a 
perpetual ticket. His career in the University was one of uninter- 
rupted progress, and on its termination he received the following 
certificate : — 
“College of Edinburgh, 20 th April 1822 . — I hereby certify that Mr 
Edward Sang has most regularly attended the Natural Philosophy Class 
during the whole of the Session now closed, that his application was ardent 
and unremitting, and the talents, ingenuity, and penetration which he dis- 
played place him decidedly above all his fellow-students. 
(Signed) “John Leslie.” 
After leaving college he commenced and continued for some 
years the practice of surveyor and civil engineer, and then became 
a teacher of mathematics in Edinburgh. In 1828 he was elected a 
Fellow of the Royal Scottish Society of Arts, and during his long 
connection with that body he brought before it some of his most 
valuable papers. We have here a list of his writings, 112 in 
number, on a great variety of subjects connected with Mathe- 
matics, Natural Philosophy, Horology, Astronomy, Engineering, 
etc., besides his great work on Logarithms. A glance over these 
gives one an idea of the diversified character of his studies, and 
suggests the query as to whether his work as a whole would not 
have been more valuable had he confined himself to a few, instead 
of dealing with so many subjects. It has been said that there is 
plausibility in asking, “not if a man can do many things well, 
hut if he lias done one thing supremely.” There are some minds — 
minds of a high order, too — fitted to attack and stick to special 
work, and it would he a wonder and a disappointment if their 
work was not supreme. Sang was not one of those ; nevertheless, 
he did many things supremely, hut could not be a specialist. The 
variety of his papers shows that clearly ; and while there is no 
time even to read over their titles, a few may he noticed in their 
order as having been received with marked favour and approbation. 
In 1829 he published a small work containing an account of a new 
method of solving numerical equations, the first of the many works 
that came from his hands. About 1830 Professor Wheatstone 
exhibited a very beautiful series of curves, produced by fixing a 
polished ball on the end of a wire and causing it to vibrate. This 
