214 B. A. Gould— Use of the Sine-formula, ete. 
have shown that the sine-formula affords such expression more 
conveniently than any other known to me; so that the well- 
established general form of the diurnal curves in these regions 
hese regions at least, both 
of these objections would be untenable it would be extremely 
easy to prove. 
In his treatise upon the Temperatures of the Russian Empire, 
published in the Supplementary volume of the “ Repertorium 
fiir Meteorologie,” Dr. Wild has taken the positions—l1st, that 
the sine-formula represents no law whatever in the diurnal 
variation, but is solely a means of interpolation ; and 2d, that 
the mean daily changes of temperature cannot be expressed by 
any simple curve. And he gives practical expression to these 
opinions by totally abandoning the employment of all general 
formulas, even for those places where the observations are 
made hourly. It is apparently in advocacy of this. singular 
' doctrine that he has made the scarcely courteous commen 
which prompt the present remarks. 
Even were the formula in question solely one of interpola- 
tion, I cannot see how in this respect the eye and free hand of a 
draughtsman could be more correct. Yet it would seem that 
Dr. Wild intends to assert this, and that he believes that the 
moments of mean daily maximum and minimum can be better 
determined by graphical approximation than by numerical 
detertnination. 
he clock 
even was always sharply determined, the observers unfailingly 
punctual, and at least the observed tenths of degrees reasonably 
trustworthy. (See “Supplement Band,” p. 36.) In such cases 
we cannot even suppose a compensation in the errors of obser- 
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