XXXIV REPORT—1863. 
Observatory, from 1857 to 1862 inclusive.” In this communication the fol- 
lowing subjects are discussed :— 
1. The disturbance-diurnal variation of the declination. 
2. The solar-diurnal variation of the declination. 
3. The semiannual inequality of the solar-diurnal variation of the decli- 
nation. 
4, The lunar-diurnal variation of the declination. 
5, The secular change, and the annual variation of the declination, dip, and 
total force. 
The values of these changes at Kew are compared with those at the dif- 
ferent Colonial Magnetic Observatories, and results of much interest and im- 
portance are obtained. 
A copy of this paper will be sent to each Member of the Committee 
of Recommendations of the Association as soon as it is out of the printer’s 
hands. 
At the request of the Astronomer Royal, the Kew curves of declination and 
horizontal force for 14th December last (a time of disturbance) were for- 
warded to Greenwich, in order that Mr. Airy might compare them with the 
records of earth-currents obtained there at the same date. 
In return Mr. Airy kindly sent copies of these latter records to Kew, and 
a comparison of these with the indications afforded by the Kew Magneto- 
graphs forms the subject of a short communication by Mr. Stewart, which is 
published in the Proceedings of the Royal Society. 
Mr. Stewart has likewise communicated to the Royal Society of Edinburgh 
a paper on “ Earth Currents during Magnetic Calms, and their Connexion. 
with Magnetic Changes,”’ which is about to be published in the Transactions 
of that body. He has likewise communicated to the Royal Society of London 
an account of some experiments made at Kew, in order to determine the 
increase between 32° Fahr. and 212° Fahr. of the elasticity of dry atmospheric 
air, the volume of which remains constant, and also to determine the freez- 
ing-point of mercury. 
This communication will be published in the Transactions of the Royal 
Society. The experiments were made by means of an air-thermometer, in 
the construction of which great assistance was derived from Mr. Beckley, 
Mechanical Assistant, while Mr. George Whipple, Meteorological Assistant, 
was of much use in observing. 
Mr. Chambers has communicated to the Royal Society a paper “ On the 
Nature of the Sun’s Magnetic Action upon the Earth,’”’ in which it is argued 
that, in causing the daily variation, the sun does not act as a magnet. 
The Meteorological work of the Observatory continues to be performed 
satisfactorily by Mr. George Whipple, and all the Staff interest themselves 
much in the business of the Observatory. 
During the past year 
130 Barometers, 
296 Thermometers, and 
22 Hydrometers 
have been verified; and Mr. Kemp, philosophical instrument maker, Edin- 
burgh, has been furnished with a standard Thermometer. 
The self-recording Barograph has been in constant operation since 8th 
November last. A suggestion by Mr. Beckley to put two papers at the same 
time upon the cylinder, the one under the other, has proved successful; and 
two traces haye thus been secured, one of which has been regularly forwarded 
