1895.] The Expansion of Argon and of Helium. 63» 



backwards and forwards through tubes containing respectively red 

 hot magnesium, red-liot copper oxide (to remove the hydrogen given 

 off by the magnesium on heating), soda lime, and phosphoric anhy- 

 dride, failed to remove the nitrogen completely. Finally, with the 

 aid of a circulating apparatus,* which ensured the passage of all the 

 gas over the hot magnesium, a product was obtained whose density 

 was found to be 19*99, oxygen being 16. The thermometer was filled 

 with this gas. 



After the pressures exerted by the argon when the bulb was sur- 

 rounded by melting ice and by the vapours of water, chlorbenzene r 

 and aniline, successively, had been determined, the thermometer was 

 heated in the vapour of quinoline, when, for some unknown reason, it 

 cracked. A new bulb, of the same glass and as nearly as possible of 

 the same size, was prepared, cleaned, and filled w T ith argon, and a 

 second series of readings made. 



Finally, the argon was replaced by air, and the second series of 

 readings for air, referred to above, began. On account of the closings 

 of the laboratory "for the summer, this series was not carried as far as 

 would have been desirable. 



Temperatures. — The temperature of the jacket, when filled with 

 steam from water boiling smoothly under atmospheric pressure, was 

 taken from Kohlrausch's " Physical Measurements." The samples 

 of the boiling liquids used were re-distilled, and were found to pass 

 over without a rise in temperature of more than a tenth of a degree, 

 in three cases ; of a fifth of a degree in the fourth case. 



Kind of 

 thermometer. 



Jin steam 

 at about 

 100°, the 

 Cor- tempera- 

 rected j ture 

 pressure.! being 

 0°. ! accu- 

 rately 

 calcu- 

 ; lated. 



Coeffi- 

 cient of 

 expan- 

 sion at 

 constant 

 volume, 

 0—100°. 



Temperatures calculated. 



Chlor- 

 benzene. 



Aniline. 



Quino- 

 line. 



Brom- 

 naphtha- 

 lene. 



1. Hydrogen 



2. Air I.... 



3. Helium . . 



4. Argon I . . 



5. Argon IT. 



6. Air II . . . 



— 1 712-56 



— 737 74 

 567-02 ; 775-18 

 517-02 ! 706-06 

 529 -54 1 — 

 511-68 | 698-79 



-003665 

 -003668 



-003663 



131 -6 



131- 8 



132 -2 



132- 15 



183-9 



183- 6 



184- 1 

 184 -1 



z 



236-35 

 [234 -9] 



236- 9 



237- 8 

 237 -1 



281 -65 

 [278 -3] 



281-5 



Air (Wiebe) 

 Temperature 

 (R. and Y.) 





0-003670 



132-1 



184 -3 

 184 -4 



235-9 

 237 -4 



280-4 



* See Rayleigb and Ramsay, 'Phil. Trans.,' 1895, A, p. 212. 



