﻿653 ] 



LVI. The Expansion of Mercury and of Quartz. 

 By N. Eumorfopoulos, B.Sc. * 



IN the March number of this magazine (p. 412) there is a 

 paper by Scheel and Heuse on the expansion of mercury. 

 In this paper two points are raised, first, the magnitude of 

 the absolute expansion of mercury, secondly, whether it is 

 permissible in work of the highest accuracy to calculate in 

 the usual way the cubical expansion of a containing envelope 

 from the linear value. Their views on this last point are 

 not very definitely stated ; it will perhaps be conducive to 

 clearness if these two points are kept separate. 



With regard to the first point, I am in perfect agreement 

 with Scheel and Heuse that the value for the coefficient given 

 by Callendar and Moss is too low, at all events below 100°, 

 and that* the mean value between 0° and 100° is approxi- 

 mately '0001826. In connexion with experiments in 

 progress on the boiling-point of sulphur on the constant- 

 pressure thermometer with a quartz bulb, I attempted, with 

 the help of Mr. B. A. Keen, B.Sc, to determine the 

 expansion of the bulb by a weight-thermometer method with 

 compensated tubes f, using Callendar and Moss' coefficient for 

 the expansion of mercury. The value at 100° was obtained 

 in steam in the usual way ; for the values at various 

 temperatures up to 250° C. an oil-bath was used of the 

 National Physical Laboratory pattern, for details of which I 

 am indebted to Dr. J. A. Harker, F.R.S. These temperatures 



518 



1 



1 10 

 I. 





































ITT 

















I, 















^ 





/> 



W 





/Y 























^ 































/ 













I 



C/U.U 



/VD/)/i 



a. Mo 



ss. 















/ 



/ 







I 



ChApi 



>C//S. 

















/ 



/ 









M 



Th/e, 



SE/V. 



(59 M 



) 













/ 











17» 



V Sc, 



{EEL,. 















/ 



1 





























100 



t°c 



£00 



300 



were read with a platinum thermometer. From curve I." in 

 the accompanying diagram it will be seen that Callendar 



* Communicated by Frof. F. T. Trouton, F.RS. 

 t See Proc. R. S. lxxxi. A (1908), p. 347. 



