ANNIVERSARY ADDRESS. 13 
Two papers by Professor Wilson are in course of publication 
in the Transactions of the Intercolonial Medical Congress of 
Australasia; one ‘‘On the development of the central canal of 
the spinal cord in the lamb,” and the other upon “A number 
of variations in human anatomy.” A first contribution to the 
myology of Wotoryctes, by the same author, will shortly appear in 
the Proceedings of the Royal Society of South Australia. 
Professor Wilson has recently written a short abstract on the 
Craniology of the Australian Aborigines, which was appended to 
Dr. Fraser’s account of that race, published by the Government. 
Printer for the Chicago Exhibition. 
Professor Threlfall has been engaged in the Physical Laboratory 
on the following matters, in most of which he has had the 
assistance of senior students and of Miss F. Martin, to whom he is 
- particularly obliged for most constant assistance :— 
Nitrogen.—He has finally proved that this gas cannot be con- 
densed like oxygen by any known kind of electrical discharge. 
It can, however, be caused to combine with mercury directly, 
forming a substance which was originally studied by Plantamour, 
from the action of ammonia on mercuric oxide, as mentioned last. 
year. The mercury nitride is found to be irreversibly dissociable 
in a peculiar manner. An account of this work was published in 
the Philosophical Magazine for January, 1893. 
Sulphur.—A. most exhaustive study of the electrical properties. 
of pure sulphur has been made in conjunction with Mr. Brearley 
and Mr. Allen (Exhibition Scholar of the University of Adelaide). 
Data were obtained upon the resistance, mode and condition, residual 
effect of charge and specific inductive capacity for different modifi- 
cations of pure sulphur. Some of the dielectric properties are so 
remarkable as to promise to render sulphur of importance in 
practical electrical work in the near future. An account of the 
theory and construction of sensitive galvanometers forms a part — 
of the paper. The galvanometer constructed by Prof. Threlfall 
some years ago is quite successful, and he is enabled to measure 
