4 SCHMITZ, Specific Heats and Volumes of Certain Alloys. 



so that they should be strictly comparable with the 

 determinations for the elements. As a test of the com- 

 parability of the present with the former series, I made 

 two new determinations for a specimen of commercial 

 aluminium included in the previous series, with the 

 following results : 



. (-1917 (exp. i) 



Former series \ , \ 



(.■1914 (exp. 2) 



•1913 (exp. I) 



Present series 



•1922 (exp. 2) 



The specific volumes given in the present paper have 



been carefully determined by weighing in air and in 



distilled water. The specimen was boiled in the water 



where want of smoothness of the surface (or the suspected 



existence of small holes) made such a course desirable. 



The usual corrections for the buoyancy of air and the 



density of water have been made, and the capillary pull 



on the suspending thread has been allowed for. The 



values given are in cubic centimetres (at the temperature 



of observation, given in brackets) per gramme. 



Copper- Tin. 

 Several methods of investigation have indicated the 

 existence of a true compound CUgSn.* The specific heat 

 of this alloy does not seem to have been previously deter- 

 mined. It was therefore a matter of interest to find 

 whether the specific heat, in this well-established case of 

 chemical combination, would show any measurable devia- 

 tion from Regnault's law. My results, given in the 

 following table, do not indicate any such deviation. 



*See for instance : Riche, Ann. de Chivi. et de Phys., 1873, Vol. 30, 

 p. 416 ; Roberts-Austen, Phil. Mag., 1879, Vol. 8, pp. 551-3 ; Le Chatelier, 

 Coniptes Rendus, 1895, '^o\. 120, pp. 835-6, and Annales des Mines, 1897, 

 Vol. Ti, p. 201; Stansfield, Froc. Inst. Mech. Eng., 1895, pp. 269-279; 

 Herschkowitz, Zeitschr. Phys. Chein., 1898, Vol. 27, pp. 148 and 165 ; 

 Maey, Zeitscht. Phys. Chein., 1901, Vol. 38, pp. 301-2 ; B. A. Report, 

 1901, pp. 75-78. 



