16 Proceedings of Royal Society of Edinburgh. [sess. 
the technical applications of some of its most recondite principles, 
The grandest works of the engineer are usually based on very simple 
scientific elements, and his skill is shown mainly in new and bold 
combinations of familiar properties. Thomson has done much 
splendid work in this direction also — witness his galvanometers 
and electrometers, his siphon-recorder, and his harmonic analyser. 
But it will never be forgotten that it was he who so applied the 
profound analysis of Fourier as to render rapid signalling possible 
through a submarine cable — thus making ocean telegraphy a mer- 
cantile success — so that we owe to him one of the grandest safe- 
guards of our empire, our practically instantaneous communication 
with our most distant and isolated colonies. 
You have already at your election meeting expressed and recorded 
your thanks to Sir William Thomson for his conduct as our President. 
You will, I am sure, with unanimity and cordiality, express your 
wishes for his comfort and success in the sphere of distinction and 
duty to which he has been called. 
Three Prizes were awarded during the past Session. 
The Gunning Victoria Jubilee Prize for 1887-90 was presented 
to Professor Tait for his work in connection with the “ Challenger 
Expedition,” and his other researches in Physical Science. His 
contributions to Physical Science are too numerous for me to 
enumerate ; but in reference to his “ Challenger ” work I may call 
attention to the ingenuity with which he has determined the 
physical properties of sea water, such as compressibility, thermal 
expansivity, and its temperature of maximum density for any given 
pressure. He has also included in his investigation the compres- 
sibilities of glass. 
The Keith Prize for 1887-89 was presented to Professor Letts 
for his researches into the “ Organic Compounds of Phosphorus.” 
The work was difficult, and the results are of great importance. 
The special interest of the investigations depends on the remarkable 
similarities, and equally remarkable dissimilarities, shown by the 
corresponding compounds of phosphorus, nitrogen, and sulphur. 
These researches have been published in our Transactions. 
The Neill Prize for 1886-89 was presented to Mr Kobert Kidston 
for his “ Eesearches in Fossil Botany.” He has devoted himself to the 
