74 



THE ROYAL SOCIETY OF CANADA 



m 



Fig.!. 



A — Glass ring. B — Glass plate. C^Copper water vessel, ff — Water inlet 

 and outlet, e — Packing box. d — Packing nut. nn — Fine glass tubes. 1 — Ther- 

 mo-element. o — Cross arm. mm — Thermocouple leads, q — Side tubes carrying 

 constantan wires. G — Heater, hh — Nichrome wire coils, j — Auxiliary nichrome 

 strip, k — Copper equalizing plate. 



Asbestos guard ring strip removed to show details of apparatus. 



tions was between 20 and 40, the thermo-element being twice moved 

 over the whole distance between the plates. To determine the influ- 

 ence of radiation, the glass plate was silvered and a series of observa- 

 tions was carried out at the same power inputs as before. The plate 

 was then blackened with soot and a similar series of observations 

 taken. As an example of the results obtained Fig. 2 is given, showing 

 the plotted observations for silvered glass. The broken curves refer 

 to the observations (uncorrected for radiation) at the four power inputs. 



