646 



Lieutenant Kenny 07i the Constants of 



that the decimal 0'002 is a very little greater than the value of Fahrenheit, 

 which corresponds to O'OOSo of the Centigrade thermometer ; such value is 

 00019444, &c., but by employing in place of this last value (for sake of simpli- 

 city) the fraction 0002, no sensible error is occasioned. I have also to remark, 

 that I have retained the increased value 0004 instead of 0-00375for expansion 

 of air, according to Laplace's recommendation for temperatures above the 

 freezing-point, having modified it for temperatures below it. 



This formula is peculiarly simple ; let us now test its accuracy by compar- 

 ing its results with those of the complete formula already submitted to the 

 Academy, and published in its Transactions. 



Table IX. 



Showing the Results of Formula [now for the first time broxiglit before the notice oftlte Academy), covi- 

 2)ared with those of the Correct Formula already before the Academy). 



Let, as before, TT indicate the height of Convent Saint Bernard above Observatory of Geneva 

 ( Vide, page 630 of this paper). 



Let, also, the heights near Montreux, as before, be designated A, B, C, and D [vide page 641 

 of this Paper). 



The column of errors of this last small Table gives results very gratifying 

 indeed : the maximum error belonging to height, Z), is still very much less 

 than the unavoidable errors of observation. 



It is, therefore, with confidence in its correct working, that I recommend 

 this modified formula to the favourable consideration of the Academy. 



