164 Mk. J. Bbtce on the Recent Progress of the 



certainly entail. A public subscription might, however, be got up ; and 

 perhaps the labours of the Society may soon so commend it to favour 

 that the list of membership may be greatly enlarged, or tlie Board of 

 Trade may be induced to aid the Society, for this as well as general 

 purposes, by an annual grant. 



Kesults. 

 (7.) Having given in the preceding brief and imperfect sketch, a 

 history of the principal steps which have been taken within these few 

 years to promote meteorology ; and shortly alluded to the class of instru- 

 ments in use, I must now call the attention of the Society to some of 

 the results which have, under the favourable circumstances referred to, 

 been already obtained. The difficulty here encountered is very great ; 

 the results are scattered through a multitude of journals, English, 

 American, French, and German ; the mere collecting and consulting of 

 which alone imply a great amount of time and labour. Imperfections 

 in the present Keport, so far as these results are concerned, can be 

 supplied on a future occasion, if health, and by favour of the Society, 

 an opportunity be afforded to me. In the portion of the Report now 

 submitted, I shall consider the subjects of Temperature, Rain and 

 Clouds, and Terrestrial Magnetism, reserving the other branches of 

 meteorology for a futui-e occasion. 



I. — Temperature and Climate. 

 (8.) The subject of atmospheric temperature, and the causes which 

 produce our actual cUmates, have received considerable elucidation of 

 late years. Much has been done in the various Arctic and Antarctic 

 voyages, by travellers in various regions, especially among the high 

 mountain ranges of Central Asia, and by balloon ascents conducted 

 under the guidance of scientific men. The discussion of the multi- 

 pUed observations of comparatively recent date, by Prof. Dove of Berlin, 

 has led to a considerable modification of the maps of isothermal lines, 

 formerly and first given by Humboldt. He has so extended the 

 researches as to have produced a series of monthly isothermals for both 

 hemispheres. Astronomy, also, has lent its aid in showing us that the 

 sun himself, the great cause of atmospheric and terrestrial temperature, 

 midergoes a periodicity in respect to the absolute quantity of heat 

 radiated by it. — The extreme difficulty of arriving at laws capable of 

 definite statement, or of being embraced in algebraic formulae, wUl appear 

 when v/e consider the constitution of our atmosphere, and the varied 

 aspect of the basis or tioor on which it rests. It consists of common 

 air and aqueous vapour which have widely different relations to heat ; 

 both elastic and capable r>f sudden and immense dilatation ; but one 



