632 
LIEUT.-GENBRAL R. STRACHEY OX HARMONIC ANALYSIS OE 
Temperature at the Seven Observatories. 
The mechanical analyser, by means of which the harmonic components of the 
temperature curves for these observatories have been obtained, is only adapted for 
computing the coefficients of the first three orders, so that the constants for the fourth 
order are not given in the published tables. 
The values of P and p were calculated from the values of the p, q coefficients, which 
are obtained by means of the instrument, in the same wmy as those for Greenwich. 
An inspection of the table C and D, wdiich are annexed, and contain a summary of 
the results, will at once show that in their main characteristics the results closely 
resemble those for Greenwich, and for this reason it will not be necessary to discuss 
them at great length. 
The amplitude of the component of the first order is, however, in all cases below 
that of Greenwich, the lowest values being those of Valencia and Falmouth, no doubt 
due to their position on the coast, with means for the year of 2“‘28 and 2°'3o, com¬ 
pared with 5°‘10 at Greenwich. 
The Kew values most resemble those of Greenwich, but the mean maximum is more 
than one degree less, and the mean for the year about half a degree less. These 
differences are probably in a considerable degree due to differences of exposure, and 
local conditions of soil, &c. 
The mean values of /x^ for the year referred to local apparent time, lie between 
205° and 220 °, that for Greenwich being 214°. The summer values are somewhat 
below the mean, and the winter values somewdiat above it, as is the case at Greenwich. 
The amplitude of the first component conforms approximately, but not so closely as 
in the case of Greenwich, to the sine of the sun’s meridian altitude, with a flattening 
of the curve in the summer months, and a tendency at some stations to a maximum 
value in May. 
The component of the second order in all cases shows the double maximum at the 
equinoxes and the minimum value in summer. The numerical values of Pj are, as a 
rule, below those at Greenwich, the yearly means varying between 0°’84 and 0°'61, 
against 1°'08 at Greenwich ; Kew, as before, most closely resembling Greenwich. 
The values of /Xo generall}^ follow the same law as at Greenwich, the epoch of 
maximum being earlier in the summer and later in the winter, this character being 
specially marked at Aberdeen, where the summer value of /x^ is — 44°, and the winter 
value 20°, a difference of 64°, or more than four hours of time, a result no doubt 
connected with the higher latitude of that station, the earlier sunrise and the 
longer day. 
The component of the third order also in all cases closely resembles that at Green¬ 
wich, P 3 having the double minimum at the two equinoxes, and a maximum in 
summer. The mean yearly value is again somewhat below that for Greenwich, 
varying from 0°'23 to 0°'38, the Greenwdch value being 0°'42. 
