C. Barus — Counter-twisted Curl Aneroid. 



127 



The column headed B is the virtual 

 tained in a way presently to be given. 



barometer, to be ob- 



Table 3 



. — Shou 



ing tht 



3 behavior 



of the Ci 



irl anei 



^oid as compared 







ivith the mercury manometer. 







6 



s 



t 



B 



6 



s 



t 



B 







Tem- 



Manometer 







Tem- 



Manometer 



Manometer. 



Curl. 



perature. 



at 25°. 



Manometer. 



Curl. 



perature. 



at 25°. 



cm., Hg. 



cm. 



°C. 



cm., Hg. 



cm.,Hg. 



cm. 



°C. 



cm., Hg. 



75-49 



5475 



25 6 



7553 



75-69 



58-80 



29-0 



75-99 



74-89 



49-40 



25-8 



74-95 



75-16 



54-30 



28-8 



75-44 



•74-58 



46-70 



26-0 



74-65 



74-36 



4630 



28-4 



7461 



73-95 



40-30 



263 



74-05 



72-97 



32-00 



28 



73 19 



75-58 



56-50 



27-3 



75-75 



76-06* 



5740 



23-1 



75-92 



75-38 



54-60 



273 



75-55 



75-29 



50-70 



231 



75-15 



74-95 



50-60 



27-5 



75.14 



74-72 



45-00 



23 2 



74-59 



74-66 



47-90 



28-0 



74-88 



7402 



38-40 



23.6 



7392 



75-59 



57 60 



29-2 



75.90 



76-01 



58-00 



23-5 



7590 



75-15 



5400 



29 6 



7550 



75-69 



54-90 



23-5 



75-58 



74-22 



44-70 



300 



7459 



75-18 



50-00 



23-5 



75-07 



73-89 



41-60 



29-8 



74-24 



74-76 



45-80 



24-2 



7470 



75-57 



57-90 



302 



75-96 



7646-j- 



60-70 



218 



76-22 



75-35 



5650 



30-2 



75-74 



75-70 



54-55 



22-3 



75-50 



74-95 



52-30 



300 



75-32 



75-22 



50-50 



22-8 



75-05 



71-92 



21-10 



29-6 



72-25 



73-94 



37 85 



234 



73 82 



75-54 



5745 



294 



75-87 



76-36 



6300 



26-0 



76-44 



7495 



52-40 



292 



75-26 



75-86 



57-30 



26-1 



75-92 



74-45 



46-60 



29-2 



74-76 



75-42 



54-50 



26.3 



75-52 



74-02 



42-70 



29 2 



74-33 



7478 



47-60 



26-2 



74-87 



75-64 



58-50 



294 



75-97 



76-34$ 



57-60 



20-8 



7602 



75-16 



54 30 



29-4 



75-49 



75-93 



5465 



21-0 



75-63 



74-33 



45-80 



29-1 



7463 



75-49 



51-10 



212 



75-20 



7338 



36-10 



29-0 



73-67 



74-86 



4520 



21-6 



74-61 



* One 



day after 





f Three da 



ys after. 



t Four days 



after. 



If the deflections [s) are platted as a function of the pressure 

 (b,) a series of detached lines are obtained, which usually lie at 

 some distance apart and are not quite straight even for a single 

 group. Inspection shows these discrepancies to be principally 

 due to temperature. It is not at once obvious how the tem- 

 perature coefficient is to be computed, unless it be assumed, 

 conformably with § 4, that the corrected loci are really straight. 



The following is a method of calculating the temperature 

 corrections without entering into unduly complex computa- 

 tions : Let s be the deflection (scale reading) at the pressure b 

 and the temperature t; let s\ b', V have a similar relation, and 

 let So, c and a be constants. For any two groups, put 



(s + s ){\+at)=bc, 



(s' + s Q )(l + at') = b'c. 



0) 



If by aid of the chart of detached lines just referred to, the 

 values of b be taken for *=* / , then 



b'-b 

 biT-Vt 



(2) 



