444 L. Waldo—Papers on Thermometry. 
burner is removed.* With this apparatus, and with the 
assistance of Mr. O. T. Sherman, a comparison between 
the German standards “Fuess 89 ” and ‘“ Fuess 50.” the 
French standards “'Tonnelot 2584” and ‘“Tonnelot 2585,’+ 
* The generai reg is that of Pierre. ace A apse sur la Thermom- 
etrie et sur la dilatation des Liquides, par J. I. Pie Caen, 1878, p. 57. 
+ the various ae ods propo osed for the dalemanigtion of the calibration 
errors of thermometers, those of Newmann and Bessel leave little to be desired for 
elega i tter of practice, however, especiall 
© ese 
methods require too much time except for the most refined work. groyene J 
method will give the calibration Prepare at nine points (inclusive of the term 
nal ore be cating, t with three columns of mercury, or at seventeen poin ate 
with f 
Let 1 = the he gt of a column of mercury occupying the half of the distance 
n the — ing and boiling points in a thermometer nearest 
ms i beside oo poi 
1,= the Rac of aco aa of mercury occupying the half of the distance 
n the gated and boiling points in a thermometer nearest 
oe se heniia oe poin 
44—)=A f= +a= the cee correction for the point midway between the 
* free reezing and boiling poin 
--42... An... Ai= these eoteeticis for Faso Bilresad. . py .. ty. . 3th of 
bet the freezing and boiling point, sragugiehegt ey 
ihe « errors of calibration at the freezing and boiling points ar 
b, b’,= the eager correction at the points corresponding to As , and Aye on 
60, 0%, ov = Rowe calibration correction at the points corresponding to 42. 
As, 52 4 on the papbsengen that the corrections at the points 
nd Ajz are each e to zer 
ddd”... des the oe wnidion at the e points corresponding to 4.1. 
iy Abs e+... Aj4 on the assumption that the corrections at the 
points A», As., Aro, Ais are each equal to zero. 
And we may w or a calibration doterhdiigallion: at fifteen intermediate points, 
the following equations which admit of rapid and — resent jon 
A, =0 As. 
Ai-=ta+ po +4cr+d Aa = Stes eden e ae 
As = fa+ b+ 404d : Ay = fa + v 
A». = §a + 3b + feo + a” Ais = da + BY + 40" + a 
ate = $a + $b ec Rei 0 
Az. = fa + $b + $e? + a” 
For 5 velibeniies computation for seven intermediate points, instead of fifteen, 
we simply omit the formule containing d, d’; ete., and conversely the computation 
