112 On an Apparatus for Measurement of Low Pressures of Gas. 



with which he has to deal. The smallest division contains only 

 1 of the globe ; consequently when a quantity of gas 



has been condensed into this space, its original tension will be 

 multiplied 1492*35 times. In one case an amount of gas, which 

 originally filled the globe, exhibited a pressure of only '5 millim. 

 when it had been compressed into the smallest division of the 

 volume-tube ; this indicates an original pressure of only '00033 

 millim. 



When measuring a tension, it is advisable to make two read- 

 ings under different condensations, and to take the mean of the 

 results. The following will give some notion of the precision 

 attainable : — 



I. At division 5 -02251 

 2 -0235 / 



Remeasured. 

 At division 5 -02281 

 „ 2 -0236J 



II. Barometer millim. : — 



Mean -0230. 



At division 10 



•19851 

 •1980J 



5 



Remeasured. 



At division 10 



•19531 

 •1967J 



5 



III. Barometer 06 millim. : — 



At division 15 



•54881 



„ 10 



•5488 y 



6 



•5501J 



Remeasured. 



At division 15 



•54641 



„ 10 



•5464 Y 



6 



•5480J 



IV. Barometer 1 millim. 



; 



At division 20 



1-20421 

 1-2069 J 



„ 15 



Remeasured. 



At division 20 



1-2082^ 



15 



1-2099 J 



V. Barometer 1*5 millim 



, : — 



At division 30 



1-91391 

 1-9080/ 



h 25 



Remeasured. 



At division 30 



1-90411 

 1-9039J 



25 



Mean -0232. 

 Mean '1982. 



Mean -I960. 

 Mean -5492. 



Mean -5469. 



Mean 1-2055. 

 Mean 1*2090. 

 Mean 1-9109. 

 Mean 1-9040. 



