j meafuring Heights with the Barometer . 739 
air^ i s t h at 0 f 12595 to 1. Mr. de la caille’s obfer- 
vations at the Cape of Good Hope, annexed to the table 
containing Mr. de luc’s, give a defeat of when the 
temperature feems to have been about 5 8°, in which cafe 
quick lilver was 11687 times heavier than air. 
Now if, from the aggregate of thefe obfervations, the 
fame method be adopted, as was made ufe of in the Bri- 
tifh, for finding the zero of the fcale, we ftiall have it as 
follows : . 
By the manometrical equation 
and reduced temperature. 
O o O 
from 25.2 to 30.5 at 33.12 
— - 26. - 35. - 3 2 ' 9 ? 
— 73-5 ~ 77 - " 3 6 - 3 2 
— 58. - jo. - 32. 
75 - - 79 - 3340 
- — 58 . ~ 33*33 
Zero at 3 3 - 5 2 
(m) It will even be found, though the calculations are not inferted in the 
table, that the hotted; of Mr. de luc’s morning obfervations, June 8th, 1758, at 
the 15th ftation, anfwering to the mean temperature of 57°*5? anc ^ which L 
conftder as the beft, becaufe no redu£lion is neceftary for the expolition of the 
thermometer, agree with the manometrical experiments, in requiring a greater 
equation than is wanted in extreme temperatures: for in this cafe, ... tne* 
mean of two obfervations gives a defe£l of for 25°»5 above freezing, which. 
is 2.57 for each degree the ratio of the weight of quickfilver to air being that 
of 12196 to 1 « 
By Mr. de luc’s equation for the air and 
obferved temperature. 
Coldeft of the morn- 0 0 0 
ing obfervations, > 25.2 to 30.5 at 33.7 
from - — d 
Coldeft of the ordi-J . T ^ „ 
nary obfervations, j 4 *9 o *7 
Hotteft of the ordi- 1 , o . - ^ « 
nary obfervations, j 7 4*5 3 . »• 
On the Dole, — 59.2 - 71.5 - 27.6 
Light houfe of Genoa, 75. - 79. - 26. 
DE LA caille’s, 58. - 30. 
Zero at 
3 2 -°3 
From 
