APPLIED TO METEOROLOGICAL OBSERVATIONS. 
131 
Table IV. — Factors to be multiplied into the mean daily range of the reading of 
a thermometer placed at the height of 4 feet above the soil, with its bulb freely 
exposed to the air, but in other respects protected from the influence of radiation 
and rain, to deduce the correction to be applied to the monthly mean reading 
at any hour, to determine the true mean temperature of the air for the month. 
Local 
mean time. 
January. 
February. 
March. 
April. 
May. 
June. 
July. 
August. 
Sep.t. 
October. 
Nov. 
Dec. 
Midnight. 
+ 0*123 
+ 0*170 
+ 0*218 
+ 0*286 
+ 0*303 
+ 0*318 
+ 0*289 
+ 0*298 
+ 0*247 
+ 0*266 
+ 0*179 
+ 0*106 
1 A.M. 
+ 0*111 
+ 0*192 
+ 0*225 
+ 0*309 
+ 0*337 
+ 0*364 
+ 0*318 
+ 0*322 
+ 0*278 
+ 0*275 
+ 0*190 
+ 0*118 
2 
+ 0*148 
+ 0*213 
+ 0*248 
+ 0*340 
+ 0*359 
+ 0*411 
+ 0*347 
+ 0*351 
+ 0*340 
+ 0*312 
+ 0*211 
+ 0*142 
3 
+ 0*152 
+ 0*223 
+ 0*271 
+ 0*370 
+ 0*376 
+ 0*446 
+ 0*371 
+ 0*369 
+ 0*395 
+ 0*331 
+ 0*211 
+ 0*154 
4 
+ 0*198 
+ 0*245 
+ 0*293 
+ 0*393 
+ 0*376 
+ 0*477 
+ 0*382 
+ 0*380 
+ 0*407 
+ 0*349 
+ 0*222 
+ 0*165 
5 
+ 0*222 
+ 0*235 
+ 0*301 
+ 0*399 
+ 0*354 
+ 0*451 
+ 0*358 
+ 0*380 
+ 0*383 
+ 0*349 
+ 0*211 
+ 0*165 
6 
+ 0*234 
+ 0*245 
+ 0*293 
+ 0*357 
+ 0*270 
+ 0*328 
+ 0*260 
+ 0*322 
+ 0*327 
+ 0*320 
+ 0*201 
+ 0*165 
7 
+ 0*234 
+ 0*223 
+ 0*271 
+ 0*256 
+ 0*146 
+ 0*154 
+ 0*145 
+ 0*193 
+ 0*247 
+ 0*257 
+ 0*179 
+ 0*177 
8 
+ 0*185 
+ 0*170 
+ 0*188 
+ 0*119 
+ 0*028 
0*000 
0*000 
+ 0*053 
+ 0*130 
+ 0*147 
+ 0*106 
+ 0*154 
9 
+ 0*123 
+ 0*074 
+ 0*015 
— 0*053 
—0*112 
-0*128 
— 0*116 
-0*094 
— 0*025 
0*000 
+ 0*043 
+ 0*106 
10 
+ 0*025 
— 0*053 
-0*143 
-0*191 
— 0*225 
—0*231 
— 0*231 
-0*205 
-0*185 
-0*184 
-0*064 
0*000 
11 
— 0*152 
— 0*223 
— 0*263 
—0*316 
-0*309 
-0*298 
-0*312 
-0*316 
— 0*309 
-0*349 
— 0*211 
— 0*154 
Noon. 
— 0*284 
— 0*340 
-0*376 
— 0*405 
— 0*377 
— 0*374 
— 0*370 
-0*380 
-0*395 
-0*468 
-0*327 
-0*248 
1 P.M. 
— 0*358 
— 0*415 
-0*436 
—0*470 
-0*421 
— 0*415 
-0*387 
-0*439 
-0*438 
— 0*505 
-0*369 
— 0*282 
2 
-0*369 
— 0*415 
-0*436 
— 0*488 
— 0*433 
— 0*442 
— 0*387 
— 0*487 
— 0*438 
— 0*451 
-0*379 
— 0-271 
3 
-0*309 
— 0*383 
— 0*414 
-0*458 
— 0*410 
— 0*431 
-0*376 
—0*410 
— 0*408 
— 0*340 
— 0*316 
— 0*224 
4 
—0*234 
— 0*298 
— 0*338 
-0*399 
— 0*343 
-0*379 
— 0*335 
—0*322 
-0*340 
-0*257 
-0*222 
-0*154 
5 
-0*136 
—0*170 
— 0*248 
—0*322 
-0*270 
-0*313 
-0*283 
-0*211 
-0*260 
— 0*156 
—0*127 
-0*095 
6 
-0*074 
-0*064 
-0*135 
—0*209 
-0*169 
— 0*231 
— 0*202 
— 0*117 
— 0*154 
-0*074 
-0*043 
— 0*048 
7 
-0*037 
+ 0*032 
-0*030 
—0*066 
— 0*056 
— 0*123 
— 0*087 
-0*030 
— 0*037 
0*000 
+ 0*011 
— 0*012 
8 
+ 0*012 
+ 0*064 
+ 0*068 
+ 0*042 
+ 0*051 
0*000 
—0*017 
+ 0*059 
+ 0*062 
+ 0*065 
+ 0*064 
+ 0*024 
9 
+ 0*049 
+ 0*106 
+ 0*128 
+ 0*119 
+ 0*130 
+ 0*092 
— 0*110 
+ 0*140 
+ 0*111 
+ 0*120 
+ 0*106 
+ 0*048 
10 
+ 0*074 
+ 0*138 
+ 0*173 
+ 0*191 
+ 0*197 
+ 0*185 
-0*191 
+ 0*193 
+ 0*167 
+ 0*175 
+ 0*137 
+ 0*059 
11 
+ 0*086 
+ 0*160 
+ 0*195 
+ 0*244 
+ 0*253 
+ 0*257 
— 0*243 
+ 0*252 
+ 0*210 
+ 0*221 
+ 0*158 
+ 0*095 
The sign + denotes that the number is to be added, and the sign — denotes that 
the number is to be subtracted. 
The use of this table is very simple : I will suppose that in January the difference 
between the mean of the maxima readings and the mean of the minima readings, or 
the mean daily range be 8°, then the amount of the correction at 4** p.m. would be 
—0-234x8°= — 1°-9. 
Again, in the month of June, suppose the mean daily range to be 19°-5, then the 
amount of the correction at 9^^ a.m. would be 
— 0-128X 19°-5=-2°-5. 
I have reason to believe that for most places the corrections in Table 11. will be 
found to be suffieient ; and although for some places we may not, by their application, 
obtain results that are perfectly accurate, they will, nevertheless, be nearer than those 
which are not corrected. 
