xxii Proceedings of Royal Society of Edinburgh. 
in Turkey. He assisted in the erection of ironworks at Ze'itun 
Buruni, and was afterwards engaged in several colleges completing 
the courses of education. In addition to this work, he proceeded 
to compile treatises on the Method of Co-ordinates, on the Differ- 
entia] and Integral Calculus, on Mechanics, Hydrostatics, and the 
Elements of Physical Astronomy. This arduous task was accom- 
plished by means of oral lectures in the Turkish language, of which 
full notes were taken by the pupils, and these notes were extended 
by the students and compared. By this means accuracy of idiom 
was secured, and the precision of the technical terms taken from 
the Arabic was ascertained. 
Sang never let an opportunity slip of helping truth or correcting ' 
error, and he took advantage of an approaching event which led to 
this, and also gave him a chance of dispelling fear and removing 
superstition. The solar eclipse of 1847 was close at hand, and was 
to be annular, and almost central as seen from Constantinople, so 
he computed its details with great care, and prepared large draw- 
ings, with a descriptive notice in French. These were presented to 
the Sultan through his Excellency Lord Cowley. Notices were 
also given in the Turkish and French newspapers, accompanied by 
lithographed drawings on a smaller scale, while prints were freely 
distributed with an explanation in Turkish. With a great roll of 
these prints under his arm for distribution, Sang often went to 
out-of-the-way places and into the bazaars. The priests were the 
worst to deal with, and were most unwilling to touch the prints, 
saying that no man should meddle with such matters, as they 
belonged to God alone. But many of them listened to reason, and 
a little sensible talk helped generally to overcome their scruples. 
The excitement was great, and the preparation of pieces of smoked 
glass was carried on most vigorously by large numbers of the com- 
munity as the predicted time of the eclipse approached. In those 
days the uneducated classes looked upon eclipses with terror and 
consternation, as in many places they still do. There are few 
amongst ourselves, even now, who are free from awe and wonder 
when there is a total eclipse, and the weird and unnatural darkness 
sends bird and beast into seclusion, and brings about a deathlike 
silence. 
The Sultan had made great preparations for the coming event. 
