1829.] 
Calculation of Heights from the Barometer. 
371 
which is precisely the height stated to have been found hy geometrical methods. 
While on the subject of barometers, I cannot help suggesting to those who keep 
registers, how much better it would be to reduce their observations to some standard 
temperature (32° for instance) and so record them : with a copy of the table sent 
herewith suspended near the barometer. This reduction would cost no trouble, no 
inconsiderable space would be saved in the register, and the observation, whether at 
the same time or at different places, might then be compared at once. It would be still 
better if the correction for capillarity were applied also, and this would be "no ad- 
ditional trouble whatever, since each observer might incorporate the correction due 
to his particular instrument on this account, with that, due to difference of tempera- 
ture ; one table giving both corrections : the latter, however, is of less consequence, if 
I am right in supposing that the tubes sent to this country are generally made of 
nearly the same interior diameter, about two-tenths of an inch. 1 aui, &c. T. 
Correction to be applied to the Barometer for expansion of Mercury. 
Temp, 
of mer- 
cury. 
In. 
14 
In. 
15 
In. 
16 
In. 
17 
In. 
18 
In. 
19 
In. 
20 
In. 
21 
In. 
22 
23° 
30 
35 
40 
45 
50 
55 
60 
65 
70 
75 
80 
85 
90 
95 
100 
+ ,010 
,003 
— ,004 
,011 
,019 
,025 
,032 
,039 
,046 
,053 
,060 
,06/ 
,074 
,081 
,086 
,095 
+ ,011 
,003 
— ,005 
,012 
,021 
,027 
,035 
,012 
,050 
,057 
,064 
,072 
,080 
,087 
,195 
,102 
+ ,011 
,003 
— ,005 
,0 1.1 
,022 
,029 
,037 
,045 
,053 
,061 
,069 
,077 
,085 
,093 
,101 
,109 
+ .01 
,003 
— .005 
,014 
,023 
,031 
,030 
,048 
,056 
,065 
,073 
,082 
,090 
,099 
,107 
,116 
+ ,013 
,001 
— ,005 
,014 
,023 
,032 
,041 
,050 
,059 
,068 
,077 
,086 
,095 
,104 
,113 
,122 
+ ,013 
,004 
— ,006 
,015 
,025 
,034 
,014 
,053 
,063 
,072 
,082 
,091 
,101 
,110 
,120 
,1291 
+ ,011 
,004 
— ,006 
,016 
,026 
,036 
,016 
,056 
,066 
,076 
,086 
,096 
,106 
,116 
,126 
,136 
+ ,015 
,004 
— ,006 
,017 
,027 
,038 
,04> 
,059 
,069 
,080 
,090 
,101 
• 111 
,122 
,132 
,143 
+ ,015 
,004 
— ,007 
,018 
,029 
,040 
,051 
,062 
,073 
,084 
,095 
,106 
,117 
,128 
,139 
,150 
Temp. 
In. 
In. 
In. 
In. 
In. 
In. 
In. 
In. 
In. 
cury. 
23 
24 
25 
26 
27 
28 
29 
30 
31 
25° 
+ .016 
+ ,017 
+ ,018 
+ ,018 
+ ,019 
,020 
+ ,020 
+ ,021 
+ ,022 
30 
,005 
,003 
,005 
,005 
,005 
,006 
,006 
,006 
,006 
35 
— ,007 
— ,007 
— ,008 
— ,008 
— ,008 
— ,008 
— ,009 
— ,009 
— ,009 
40 
^018 
,019 
,020 
,021 
,022 
,022 
,023 
,024 
,025 
45 
j030 
,031 
,033 
,034 
,035 
,036 
,033 
,039 
,040 
50 
,041 
,043 
,045 
,047 
,049 
,050 
,052 
,054 
,056 
55 
,053 
,055 
,058 
,060 
,062 
,064 
,067 
,071 
60 
,061 
,067 
,070 
,073 
,076 
,078 
,081 
,084 
,087 
65 
,076 
,079 
,083 
,086 
,089 
,092 
,096 
,099 
,102 
70 
,087 
,091 
,095 
,099 
,103 
,106 
,110 
,114 
,118 
75 
,099 
,103 
,108 
,112 
,116 
,120 
,125 
,129 
,133 
80 
,110 
,115 
,120 
,125 
,130 
,134 
,139 
,144 
,119 
85 
+22 
,127 
,133 
,138 
,1 13 
,148 
,154 
,159 
,161 
90 
,133 
,139 
,145 
,151 
,157 
,162 
,168 
,174 
,180 
\ 145 
,151 
,158 
,164 
,170 
,176 
,183 
,189 
,195 
100 
,156 
,1631 
,170 
,177 1 
,184 
,190 
,197 
,204 
,211 
Note by the Editor. 
We have substituted a more correct table for that of our correspondent, which 
beino- taken from Daniel was affected by the error noticed in our last number, p. 
323.° The error in the extreme case was ,028. nearly 30 ft. in altitude. The ex- 
pansion of the mercury had been diminished by the mean value ot the dilatation of 
glass, whereas nothing can be more evident than that the latter should be neglected. 
