200 Table for ascertaining Heights, &c. (Apri, 
Taste II, of Multipliers to correct the approximated Height for the 
Temperature of the Air. 
Temp. of Air. Multiplier. Temp. of Air. | Multiplier. Temp. of Air. Multiplier. 
Q & 6 
32 1,000 52 1,042 72 1,083 
38 1,002 53 1,044 73 1,085 
34 1,004 54 1,046 74 1,087 
35 1,006 55 1,048 75 1,089 
36 1,008 56 1,050 76 1,091 
37 1,010 57 1,052 77 1,094 
38 1,012 58 1,054 iyi 1,096 
39 1,015 59 1,056 79 1,098 
40 1,017 60 1,058 80 1,190 
41 1,019 61 1,060 81 1,102 
42 1,021 62 1,062 82 1,104 
43 1,023 63 1,064 83 1,106 
44 1,025 64 1,066 84 1,108 
45 1,027 65 1,069 85 1,110 
46 1,029 66 1,071 86 1,112 
47 1,031 67 1,073 87 1,114 
48 1,033 68 1,075 88 1,116 
49 1,035 69 1,077 99 1,118 
50 1,037 70 1,079 90 1,121 
51 1,039 7 Neer T, 088 91 Vase 28 
Enter with the mean temperature of the stratum of air traversed ; and multiply 
the approximate height by the number opposite, for the true altitude. 
The table of Tensions (tab. I.) is still avowedly imperfect. We see that 
the force of vapour for 210°, as found by observation, differs several hun- 
dredths of an inch from the formula of either Datron, Urs, or Trep- 
GOLD, although only two degrees distant from the fixed point 212°. Nor 
can it surprise usto find it so, because its experimental determination, by 
heating vapour inclosed within the thick glass of a barometer tube, is ne- 
cessarily subject to much more uncertainty than the obvious measurement 
of the boiling point, under a given pressure of the air. On the moun- 
tains of India, at Simla, Sabatha, Chirra Piinji, and even Spité, where- 
ver in short there may be observers in possession of good barometers, 
the power exists of rendering an essential service to physics by fixing 
so many points on the scale of tensions, in the latter more unexception- 
able manner. For instance, an observer at Chirra, by carefully noting 
the heat of his boiling tea-kettle every morning, and inserting it in his 
register, together with the accurate height of the barometer, would de- 
termine that part of the thermometric scale corresponding to 25 and 
26 inches of pressure. So with observations at SAgur, for 28 inches; 
at the Nilgherries for 21 inches; and in the Himdlaya for even 15 
inches : and I hope that this notice may have the effect of inducing this 
new and interesting species of synthetical research, as a check upon the 
scales framed on an opposite system in the laboratory. 
