38 



PROCEEDINGS OF THE AMERICAN ACADEMY 



TABLE IX. 



Range. 



100 to 200 

 100 to 200 

 -15 to 110 



—6 to 40 



to 100 



-21 to 103 



—3 to 102 



About 

 to 100 



About 

 to 100 



.32 to 212 



Gradua- 

 tion. 



Length 

 occupied 

 by 1^ C. 



0.1 C. 

 0.2 0. 

 0.2 C. 



mm. 

 0.1 C. 

 0.5 F. 



0.1 C. 



Arbitrary 

 equal 



volumes. 



Arbitrary 

 equal 



vol limes. 

 1=.0 F. 



cm. 



05 



0.32 



0.9 

 0.5 

 0.46 



38 

 0.32 



0.31 



16 



October, 1878. S. W. Ilolman. 



Casella.j 



Baudin. 

 BauJin. 

 Welch. 



Geissler 



Fastre. 



Fastr6. 



Kew Register, 



1873, -4, -8. 



1876-77. 

 October, 1878. 

 July, 1853. 



(?) 

 1851. 



1851. 



(Quite old.") 



S. W. Uolman. 



• S. W. Holman. 



Physical Labora- 

 tory, Johns Hop- 

 kins University. 



S. W. Ilolman. 



Professor Barlier, 

 University of 

 Pennsylvania. 



Chemical Labora- 

 tory, Johns Hop- 

 kins University. 

 I Professor Gibbs, 

 ( Harvard College. 



( Profe?sor Gibbs, 

 I Harvard College. 

 I Harvard College 

 ] Observatory. 



It is always somewhat unfortunate, but usually unavoidable, to have 

 the stem of the thei-mometer at a temperature lower than that of the 

 bulb, and the correction from this cause increases about as the square 

 of the temperature of the bulb. Among the discussions of the methods 

 of correction for this error may be cited those of Kopp, Regnault, 

 Holtzman, and, more recently, Wullner * and Mills. f After a careful 

 experimental trial and consideration of these, it appeared to me that, 

 for the present purposes, results fully equal to the requirements would 

 be obtained by the use of a stem bath as above described. 

 Let s = mean temperature of this bath. 



t = actual temperature of bulb (to be determined). 



0.000156 = coefficient of apparent expansion of mercury in 



glass. 

 n =z length of mercury column in units of the scale graduation 



at temperature s. 

 r = direct reading of thermometer corrected for calibration 

 error. 

 Then 



t = r-\- 0.00015G (t — s)7i, 

 or approximately 



t = r -{- 0.000156 (r — s)n, 



* Leln-huch der E.xperiniental-Pliysik, iii. 312. 

 t Proc. Royal Soc. Edinburgh, xxix. 569. 



