[ fi'7 ] 
XIT. Harmonic Analysis of Hourly Ohscrvafions of Air Teiii'perature and Pressure 
at British Observatories .— Part T. Tem-perature. 
By Lient.-Oeiieral Pt. Strachey, F.R.S., Cha.iirnan of the Meteorolor/ical Council. 
Received January 20,—Read March 2, 1893. 
[Plates 19-23.] 
The Meteorological Council have lately published a volume entitled ‘ Harmonic 
Analysis of Hourly Observations of Air Temperature and Pressure at British Obser¬ 
vatories.’ It was thought preferable that this publication should be limited to the 
series of Tables giving the computed values of the harmonic constants, with a brief 
introduction explaining how the calculations had been carried out, and that the 
discussion of the results should b(! embodied in a separate memoir, which I hoped to 
comimmicate to the lioyal Society, an intention which I now realize. 
I have annexed to the present communication a selection of such of the Tables 
given in the volume referred to as appear necessary for my present purpose, and I 
have added a series of graphical representations of some of the results of the 
computations, which will facilitate the study of the subject. 
I have also thought it convenient to reproduce, with some few modifications, the 
explanations, contained in the introduction of the same volume, of the metliod 
according to which the computations it contains wei'e made. 
The series of Tables to which I have referred give the results of computations com¬ 
menced by myself, and completed in the Meteorological Oftice under the supervision 
of Mr. K. Curtis. 
The computations, as originally undertaken, were designed to supply the harmonic 
analysis of the hourly observations of temperature and pressure made at Greenwich 
Observatory, in each case for twenty years, which were published in 1878. 
Subsequently it was determined to extend the investigation, as a part of the regular 
routine of the Meteorological Office, so as to obtain the harmonic constants from the 
photographic records of temperature and pressure of the self-recording instruments at 
the seven observatories maintained by the Meteorological Oflice, viz., Valencia, 
Armagh, Falmouth, Glasgow, Stonyhurst, Aberdeen, and Kew, for a series of twelve 
years. 
With a view to reducing the necessary labour, the computations of the harmonic 
MDCCCXCIII. —A. 4 K 18.10.93 
