318 Proceedings of the British Association. 



London, after similar precautions. The later researches of Forbes 

 and Melloni on this subject, related to the connexion of these dis- 

 coveries and the facts thus developed, with the undulatory theory. 

 The report contained some remarks on the clearness with which 

 the chronological order of the discoveries is marked in this case, 

 and the consequent impossibility of any of those disputes which 

 have sometimes (ended to disturb the harmony of scientific in- 

 quiries. The continental philosophers have the merit of devising 

 and bringing to perfection the instrument, by the aid of which 

 alone, any discoveries in this very delicate field of researcli could 

 have been expected. Prof. Forbes is the author of the discovery 

 of the polarization of heat in all its branches, and from all its 

 sources. 



Prof. Forbes gave an abstract of his Supplementar^y Report on 

 Meteorology. At the last meeting of the Association, he had 

 been requested to make a report on the progress of meteorology 

 since the period of his former report, which was drawn up in 

 1833. In obedience to that request he now came before them. 

 He had distributed the matter of this report under the same gen- 

 eral heads as those under which he had formerly treated of the 

 several subjects. These were Temperature, Pressure, Humidity, 

 Wind, Clouds, Rain, Electricity, Meteors, and suggestions on the 

 first of these heads. In the report he had entered fully into the 

 subject of the instruments used for measuring temperature, with 

 their improvements, defects, and the cautions to be observed in 

 using them. He enlarged on the decrease and accumulation of 

 heat, and the curves which were used for elucidating these sub- 

 jects. He spoke of the temperature decreasing in a geometrical 

 series as you ascend through arithmetically increasing heights, 

 the temperature being supposed constant, and entered on an ex- 

 amination of the paradoxical conclusion at which Poisson had 

 arrived, that the upper surface of the atmosphere was, in conse- 

 quence of the extreme cold there existing, in a state which he 

 termed liquefaction. He observed that there are reasons for con- 

 cluding that the temperature of space itself entirely beyond the 

 atmosphere of the earth, was not so cold as Poisson seemed to sup- 

 pose the highest portions of our atmosphere ; but that, indepen- 

 dent of this opinion, there were other causes in operation quite 

 sufficient to limit the extent of the atmosphere, without the aid 

 of this startling supposition, and which limited height might be 



