ANNIVERSARY ADDRESS. 33 
14. The Circulation Kymoscope, an arrangement for demonstrating many 
of the Physical phenomena of the Circulation. 
15. The Interference Kymoscope, an apparatus for demonstrating many 
of the phenomena of wave-motion. 
Pharmaceutical Journal— 
16. On the so-called Eucalyptus Honey. 
17. Report on the Koch Method of Treating Tuberculosis. 
In the Physical Laboratory at the University, Professor Threl- 
fall, aided by the Demonstrator, Mr. J. A. Pollock, and advanced 
students, has been engaged in making investigations most of which 
have occupied him at different times since 1888. One of these is the 
measurement of the magnetic effect of displacement currents, 
based on the use of a circuit of fused quartz in an alternating 
field. Success has not-yet been secured owing to the strong dia- 
magnetic properties of the quartz, and also for the want of suflicient 
means for producing strong magnetic fields. Investigations have 
also been made with regard to a static-gravity-meter depending on 
fused quartz threads, an investigation of the physical properties. 
of which was published in the Philosophical Magazine for 1890 
and which agreed with some results obtained by Prof. Boys and 
just published, though not seen by Prof. Threlfall at the time his. 
paper was written ; the Sydney results were probably the more 
accurate of the two, as the research was more elaborate. Since 
then the constants have been verified, and a very curious increase: 
of rigidity found out ; it occurs when the fibres are heated, and it. 
is not explained by the expansion of the fibres by heat. This was 
worked out by the Professor and some of the students. Experi- 
ments upon nitrogen have occupied a good deal of time, as the 
Professor has no assistance of the kind required in this investiga- 
tion. He has, however, succeeded by a partly original process, 
in getting a continuous flow of nitrogen ina state of purity, which 
it is believed has never been approached before, and he has proved 
that nitrogen forms acompound with mercury under the influence 
of the electrical discharge, and he has established the identity of 
this compound with one partially studied by Shonbein, and formed 
by acting with ammonia on mercuric oxide. The exact compo- 
C—May 4, 1962. 
