Isometrics of Liquid Matter. 



343 



rounding 1 1 with a jacket mm of circulating cold water, 

 coming directly from the hydrant. The meniscus in s s may 

 be raised or lowered, and coloured when faded, by inserting 

 filamentary glass suction-tubes into the capillary (§ 14). 

 Water free from air scarcely attacks steel. 



14. To graduate this gauge, I compared it with a large 

 Bourdon gauge* reading from to 1000 atmospheres (§ 1). 

 This comparison is a check on both instruments, though it 

 affords no means of testing the standard atmosphere employed. 

 Since both gauges are based on Hooke's law and provided 

 with suitable scales of equal parts, relations are well indicated. 

 In Table I., 2<2 , 2a 1? and L denote the internal and the 

 external diameters, and the length, respectively, of the steel 

 tube q q, fig. 4 ; 2p is the bore of the capillary s s. 



Table I. — Comparison of Tait Gauge and Bourdon Gauge. 



2a = *54 centim. ; 2a x = 1*00 centim. ; L = 100 centim. ; 

 p = *034 centim. 



Time 



— 



15 m. 



30 m. 



45 m. 



75 m. 



1 

 90 m. 



Gauge . . . 



Bourdon. 



Tait. 



Tait. 



Tait. 



Tait. 



Tait. 





atm. 



centim. 



centim. 



centim. 



centim. 



centim. 









1-90 



210 



2-00 



2-18 



2-16 





100 



3-58 



3-70 



3-60 



3-85 







200 



5-20 



5-50 



5-35 



5-55 







3U0 



7-05 



7-25 



7-20 



7-45 



7-30 





400 



870 



900 



8-90 



9-10 







500 



10-50 



10-72 



10-70 



10-85 







600 



112-50 



12-50 



12-45 



12-55 



12-70 





700 



14-10 



1410 



14-10 



14-20 







800 



15-65 



15-70 



15-70 



15-85 







900 



17-22 



17-20 



17-30 



17-45 







1000 



18-80 



1900 



19-00 



19-10 



19-20 





900 



16-62 



16-70 



16-80 



16-80 







800 



1465 



14-70 



14-63 



14-70 







700 



12-80 



12-80 



12-75 



12-92 







600 



10-95 



11-00 



1100 



11-12 



11-00 





500 



9 30 



9-28 



923 



9-35 







400 



7*55 



7-55 



7-50 



7-60 







300 



5-95 



6-00 



6-10 



6-15 



5-85 





200 



4-50 



4-55 



4-60 



460 







100 



3 04 



312 



345 



3-20 











1-74 



1-90 



1-90 



2-00 



1-60 



Rate in centimetres \ 

 per atmosphere... J 



•0169 



•0171 



•0172 



•0172 





t Break in the measurements. 

 Furnished "by the Societe Genevoise. 



