60 REPORT—1843. 
widely distributed over the surface of the globe; and that indefatigable officer 
has again sailed for the coast of China and the Pacific, furnished with an 
improved magnetic equipment, including the portable magnetometer appa- 
ratus and a Fox’s inclinometer and intensity instrument for observations at 
sea. 
The observations from Captain Blackwood’s expedition have begun to 
arrive, both those with Mr. Fox’s instrument at sea and with the portable ap- 
paratus on occasions on shore. The observations of this expedition promise 
to be of great value, from the zeal and intelligence which those already re- 
ceived evince on the part of Lieut. Shadwell and Mr. Evans, under whose 
particular direction this branch of the public service has been placed by 
Captain Blackwood. 
No expense whatever has been incurred in the present year, but your Com- 
mittee pray the continuance of the grant made to them at the last meeting to 
meet such demands as may arise. 
Signed on the part of the Committee, J. F. W. HerscHet. 

Report of the Committee appointed for the Reduction of Meteorological 
Observations. By Sir J. F. W. Herscuen, Bart. 
Every exertion having been used to complete the series of equinoxial and 
solstitial observations during the years 1835, 1836, 1837, 1838, whether by 
writing to parties who have communicated observations, for duplicates of 
missing series, or by searching the records of observatories, meteorological 
registers, scientific journals and periodicals, these endeavours have proved so 
far successful, that at length 334 sets of observations have been collected, 
made at sixty-nine distinct stations. A synoptic statement of these, with the 
geographical elements of the stations, the names of the observers or commu- 
nicators of the observations, and other particulars as far as they could be col- 
lected, or are necessary for our present purpose, is annexed to this report. 
See Appendix (A.). ‘ 
It will be at once seen on inspection of this synopsis, that although at a 
few stations (as London, Greenwich, Brussels, Port Louis, Markree, Cadiz) 
consecutive series, extending over a period of three complete years, have been 
procured (within the limit assigned to these reductions), yet that this is not 
the rule but the exception; and that, taken altogether, the observations form 
anything rather than a connected whole. Under these circumstances, the 
only point of view which seemed to promise any distinct and definite results, 
bearing reference to causes prevailing over extensive regions, was that of the 
barometric fluctuations, considered with a view to the propagation of atmo- 
spheric waves, which, it is manifest, can only be traced over any considerable 
tract of country by this method of inquiry. It is accordingly to these, and 
to these only, that my attention has been directed ; using the observed tem- 
perature (where the original observations have not been corrected by the 
observers) merely as elements of reduction, and referring to the registered 
state of wind and weather, whenever such reference has been considered 
elucidatory of any point suggested by the main branch of the inquiry. 
If we consider the trifling depth of the ponderable atmosphere regarded as 
an envelope of the whole globe, the interruption and obstacles offered to its 
oscillatory movements as a whole by the configuration of the continents and 
the distribution of mountain chains, but above all, by the vast and capricious 
variety of local causes affecting the temperatures of particular districts, and 

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