266 ABSTRACTS OF THE MAKERSTOUN OBSERVATIONS, 1843. 
The smaller the second is the more nearly will the approximate curve resemble the true curve in form, and 
the smaller the first the more nearly will the approximate curve approach the true curve in position, 
In the foregoing Table, the range of the errors, and their mean for the 12 months (independent of sign), 
are given for each couple of hours, The hours which seem best to satisfy the two conditions are— i 
1st, 18" and 5" Gottingen, or 5° 10™ a.m. and 4" 10™ p.m. Makerstoun mean time. 
Dds 2OP and) 10", © xcnetn< or 9%10™4.mM, and 9" 10™ pa. 
Gdabo2 and el Ol eae or 5° 10™ a.m, and 11" 10™ a.m, 
4th, 19 and 6% ......... or 6410™ 4m. and 5 10™ p.m, 
bth, 232 andilO™ eo. oeesas or 10" 10™ a.m. and 9" 10™ p.m. 
Oths 222" and: O80 sees ce or 9°10™am. and 8" 10™ pM. 
The first couple of hours is considerably superior to any of the others, the mean of the errors being only 
0°24, and their range only 0°-68, while the error for the year is only — 0°17. The second couple of hours is 
more convenient. For ordinary purposes, the maximum and minimum register thermometers seem sufficiently 
accurate.* 
TABLE V.—Diurnal Ranges of Temperature for each Civil Day in 1843, as deduced from the 
Observations of the Maximum and Minimum Register Thermometers. 
January. | February.) March. il. . . \September.) October. |November.| December. 
° 
17-6 
16-8 
12.4 
13-9 
31-8 
23-9 
29-5 
36-5 
29-3 
24-6 
15-6 
15-7 
21-0 
28-3 
15-3 
28-9 
20-5 
20-5 
30-9 
COWH MP wre 
Mean | 9-0 
* There are three couples of homonymous hours given in the Table, but only one couple gives satisfactory results. It will be 
found. that twelve or thirteen combinations of hours, haying the common interval of eleven hours (nearly the critical interval), will 
give a mean error for the year from a third to a half less than that from the twelve combinations of homonymous hours, the combina- 
tions commencing with 104 p.m, and 9" 4.M., 11" p.m. and 10" 4.M., and so on to the twelfth or thirteenth couple. 
