40S 



Results of Makeestoun Observations, 1844. 



TABLE IV. — Errors of the Approximate Mean Temperatures, deduced from one or two Daily 

 Observations, for each Month, and the Year 1844. 



5th. 10^ IQin A.M., and 10'' 10™ p.m. 6th. 5'' 10™ a.m., and 11'' 10™ a.m. 

 8th. 7'' lO™ P.M. 9th. Ma.x. and Min. 



Approximations to the Monthly Mom Temperatures. — -The values of the approximations to the monthlv 

 mean temperature, from observations at two hours each day, may be considered inversely proportional to the 

 mean of the errors ; they may also be considered inversely proportional to the range of the errors, whence the 

 values ^vill be inversely proportional to their product. By means of this measure, we find the values of thi- 

 appi-oximations to be in the following order, commencing with the highest : — • 



1st. 5" ID"' A. M., and 4'' 10'" p.m. 2d. 9'' 40'° a.m., and IC" lO"" p.m. 3d. 9'' 40'^ a.m.. and 9''40'np.M. 

 4th. IC' 10"" A.M., and 11" 10'" p.m. 

 7th. 9'' lOi" A.M., and 9'' 10"' p.m. 



The best approximation to the mean for the year is given by the observations at 10'' 10™ a.m. and 

 11'' 10'" p.m., which differs oidy 0"-01 from it. If the approximations to the mean for the year should be nearly 

 constant from year to year, tlien the best approximations to the monthly means should be determined by em- 

 ploying the mean error after correcting by the yearly difference. Thus, if the monthly means for 9'' 40™ a.m. 

 and 10'' 10™ P.M., are corrected by +0'23 — the correction for the yearly mean from the observations at the 

 same hours — the average error of the monthly means is only 0°-13. 



The following are the errors of the yearly means, as deduced from each couple of homonymous hours : — 

 jh lom Ob 10". 3b 10" Ik 10" S' 10" &> 10" Tb 10" fci' 10- S' 10" 10* 10" lli> 10™ 

 + 0'-96 +0°-"6 +0°-34 -0°-22 -0°-75 -0°-92 -0°-87 -0°-69 -0°-31 +0°-17 -(-0°-69 



,.M. and P.M. 



12b lOm 

 + 0°-83 



The following are the eiTors of the yearly means, as deduced from two observations made at intervals of 

 1 1'', nearly the critical interval for the year : — 



2'' 10' 

 1 10 



+ 0°-78 +0°-62 +0°-29 



lib lOm P.M. 121. 10" A.M. 

 10 IP A.M. 11 10 A.M. 



+ 0°01 +0°-41 



+ 0°-71 



5h 10" 6'' 10" T' 10" 



4 10 5 10 6 10 



-0°-09 -0°-32 -0°-32 



S" 10" 

 7 10 



9b IQu, 



8 10 



lOk 10" 

 9 10 



0°-14 +0''-09 +0°-49 



The average of the errors for the 12 homonymous hours is 0°-63, and the range of errors is l°-88. 



12 couples at the critical interval is 0°'36, and the range of errors is 1°-10. 5 



Observations at each of the following three couples of hours which are at the critical interval, give the 

 mean for the year to 0°-01, — namely, 11'' 20™ p.m. and lOi" 10™ a.m., S"" 20™ a.m. and 4'' 10™ p.m., and 8'' 20" 

 A.M. and 7*' 10™ p.m. 



i 



