178 



HoTborn and Day — Gas Thermometer at 



rnination of the distance between the two points, 161-60 mm con- 

 tained variations of only 0'02 mm in the individual readings. 

 An error of OI per cent in the determination of the supple- 

 mentary volume would cause an error of 1° in the temperature 

 at 1000° as determined at the lower point. 



For the verification of the method several measurements of 

 the volume of the bulb at 0° were made. For the first plati- 

 num bulb the determination by filling with water and weighing 

 yielded 208-49 cm3 , the volumetric determination 20845 and 

 208-5 L cmS ; for the second bulb the results obtained by the two 

 methods were 195-87 and 195 - 91 cm3 respectively. 



Table XII contains the temperature measurements at the 

 two different pressures. H and t represent the pressure meas- 



Table XII. 



1899 



H 



(mm.) 



t 



H' 

 (mm.) 



t'-d 



6 



t-i' 



July 22 



871-71 



553-0° 



524-13 

 526-38 



550 

 556 



9° 

 6 



+ 2-0° 

 — 3-4 



+ 0-1° 



— 0-2 





877-37 



558-7 



526-80 

 528-35 



557 



562 



8 

 



+ 1-5 

 — 2-9 



— 0-6 



— 0-4 





1339-50 



1022-7 



663-06 

 666-71 



1015 

 1030 



4 

 1 



+ 6-3 

 -7-6 



+ 1-0 



+ 0-2 



Aug. 2 



848-68 



531-1 



514-76 



517-07 



527 

 533 



9 



8 



+ 2-5 

 — 2-9 



-I-0-7 

 + 0-2 





855-11 



537-4 



5i7-76 

 519-05 



535 

 539 



5 

 1 



+ 1-6 

 — 1-6 



+ 0-3 



—o-i 





1047-86 



728-2 



581-57 

 585-81 



721 



734 



9 

 9 



+ 5-3 

 -7-3 



+ 1-0 

 + 0-6 





1055-69 



736-1 



585-80 

 586 89 



734 

 737 



8 

 9 



+ 1-1 

 — 1-9 



+ 0-2 

 + 0-1 



Aug. 3 



952-97 



633-9 



551-09 



558-78 



629 

 651 



4 



4 



+ 3-5 



— 18-4 



+ i-o 



-f-0-9 





974-06 



654-8- 



559-11 

 560-58 



652 

 656 



5 



7 



+ 1-6 

 — 2-4 



+ 0-7 



+ 0-5 





1242-43 



924-5 



638-41 

 639 87 



921 

 926 



4 



7 



+ 1-5 

 — 3-1 



+ 1-6 

 + 0-9 





1243-62 



925-8 



639-62 

 639-63 



925 

 925 



5 

 6 



— 0-6 



— 0-6 



+ 0-9 

 + 0-8 



ured upon barometer and manometer, and the temperature cal- 

 culated from it for the readings made at the uppermost point ; 

 IF and t' — 8, the corresponding magnitudes for the readings- 



