620 
LIEUT.-GENERAL R. STRACHEY ON HARIMONIC ANALYSIS OF 
Then, without moving the slide, the value of P will be found on the scale, showing 
logji?, opposite the graduation on the upper edge of the slide corresponding to log 
sin X ; or log P = log pj — log s'm 
The first series of Tables in the volume spoken of deal with Greenwich aii’ tempe¬ 
rature, the next refer to Greenwich pressure. Then follow the results obtained by 
the mechanical analyser for the seven observatories, first those dealing v’ith tempera¬ 
ture, and next those for pressure. 
The Tables for each series (a few of which only are reproduced with this paper) 
are arranged as follows :— 
No. I. gives the values of the p, q coefficients, in the case of Greenwich, for the 
first four orders for each year and for each montli, and for the seven observatories of 
the Meteorological Office for the first three orders. The mean values, in the case of 
Greenwidi, for each series of live years, as well as the means for the whole 20 years, 
are also given; and for the seven observatories for the period of 12 years. 
No. II. is deduced from No. I., and gives in like form the values of P and /r for the 
four, or three components (as the case may be) for each year and month, and the 
corresponding means. 
It will be observed that, in a few cases, p, has a negative sign, which implies, as Avill 
be further explained, that the epoch of maximum is thrown back before midnight. 
No. III. is derived from No. I., and gives the mean annual values of the p, q coeffi¬ 
cients for each year, with the five-year and 20-year means as before. 
No. IV. is also derived from No. I., and gives the means of the several monthly 
values of the qo and q coefficients for the 20 years. Ttible A, annexed to the present 
paper (p. 639), reproduces the results for the Greenwich observations, and Table C 
those for the seven observatories. 
No. V. is derived from No. II., and gives the mean annual values of P and p for 
each year, with the five-year and 20-year means. 
No. VI. is also derived from No. II., and gives the means of the several monthly 
values of P and p for the 20 years. 
No. VII. brings together the monthly mean values of P and p for the first four orders 
of components, for the four five-year periods over which the observations extend; the 
jdiase of maximum being in this Table stated in apparent time, instead of in Tiiean 
time, as is done in the others. Table B, which is annexed to this paper, gives these 
results for the Greenwich observations, and Table D those foj- the seven observatories. 
No. VIII. shows the mean monthly values of P and p, obtained from the mean 
hourly values for each month and the entire year for the whole series of 20 }'ears, as 
given in No. IX. These values will be seen to differ from those supplied by No. VI., 
and would be the values of P and p, deduced from the mean values of p, q given in 
No. IV. The differences are due to No. VI. giving the means of the whole of the 
separate values obtained from the observations of the separate years and months, 
while the results in No. VIII. are obtained from the mean of the hourly values for 
