88 



Mr. S. A. Sworn. 



Thermometer. 



Temperature. 



. P2- 



K. 



2220 

 Pi = 525 mm. 





6541 

 655 V 

 636 J 

 544 

 445 

 363 



1 



y -1005 mm. 



i 



J 





19-5^ 



6681 



659 y 



654 J 



561 



424 



j 



i> -1243 mm. 



1 



J 





20-5° 



6G91 

 664 J 

 574 

 414 



^ -1070 mm. 



Mean K = '111 mm. ± '005. 

 = 0-0065° ± 0-0003. 



The value of K for the various thermometers was found to be as 

 follows -. — 



Thermometer. K. 



2220 0-0065° ± 0-0003 



2221 0-0098° 1 



2218 0-0087° ± 0-0006 



2219 0-0104° ± 0-0013 



4976 0-0051° ± 0-0004 



711179 0-0105° ± 0-0004 



Mr. Sworn concluded from his results that K is a constant not 

 affected by a change in the rate of rise in temperature, and not appreci- 

 ably different in different parts of the tube, if the average value of K 

 over a space of several millimetres is always taken. 



The Fundamental Interval arid the Coefficient of Internal Pressure. — The 

 zeros were determined by plunging the thermometer into a mixture of 

 finely pounded ice and distilled water. Samples of ice were frequently 

 prepared from distilled water, which had for some time been kept in a 

 partial vacuum of 50 — 100 mm. Norwegian ice was also used, and 

 within the limits of experimental error was always found to give the 

 same results as the specially prepared ice. The purity of the ice was 

 invariably controlled by testing for chlorides, by the Nessler test, and 

 by evaporation to dryness in a platinum basin. In order to be sui'e 



