218 B. A. Gould—Use of the Sine-formula for the 
fully justifiable to employ a similar formula for discussing a 
small number of daily observations made at places not too 
remote and in which the topographical conditions are not too 
different. The results so cutened thus far fully confirm this 
view, and especially those relative to the variations of tempera- 
ture. 
In his treatise on the temperature of the Russian Empire, 
Dr. Wild arrives at a conclusion which he expresses as follows 
p. 95): “For interpolating omitted hours, especially those of 
the night, the formula of Lambert and Bessel can,—according 
to Theorem 11 regarding the form of the curve of the diurnal 
period in the temperature,—only be applied, at most, for en- 
tirely maritime climates. For all places of which the situation 
is in any degree continental, it must be totally rejected, on 
account of the sudden bend in the curve at the time of sun- 
rise, which it is only capable of. representing by the employ- 
ment of very many terms (10 or more), even for complete series 
of hourly observations.” 
That this conclusion does not hold good for Cordoba will, I 
think, be manifest to any one upon inspection of the preceding 
table, which exhibits the residuals between the monthly means 
of hourly observations and the corresponding values afforded 
by the monthly sine-formulas with four variable terms. Cor- 
doba is situated about 400 miles from the La Plata in a straight 
line, and about 620 from the Atlantic, its position being pre 
éminently continental. Buenos Aires, however, for which 
See my use of the sine-formula is so sharply censured by Dr. 
ild, is a seaport. 
The residuals which result from the use of only three varia- 
ble terms are by no means important, though of course some- 
what larger than those given in the table. There is a certain 
tendency to grouping of their signs by triplets which shows 
that the fourth term may be added with advantage ; yet neither 
their order of magnitude nor the fluctuation of their signs gives 
token, even in this case, of any such discordance between the 
formula and the true law of variation as Dr. Wild thinks he 
has discovered for the Russian stations, Here at least it may 
be said of the daily curve, “Natura non facit saltum.” As 
regards the magnitude of the residuals, no one can be more 
conversant than Dr. Wild with the numberless influences 
which, in spite of every care, affect the accuracy of observa 
tions, nor yet with those analogous ones in the varying an 
intricate combinations of transient atmospheric conditions, 
which by their perturbations throw a veil over the true funda- 
mental law. And I think he cannot fail to acknowledge that 
the true law is here expressed by the sine-formula closely 
