116 Second Supplement to the Catalogue of [No. 31 



which are then more powerfully warmed, and which is but partially coun- 

 teracted by the opposite current in the lower strata. 



In concluding this communication, I beg respectfully to submit to the 

 consideration of the eminent meteorologists here present, that it is very 

 important towards the progress of this science, that the propriety (in such 

 discussions as the present) of separating the effect of the two elastic forces 

 which unite in forming the barometric pressure should be either admitted 

 or rejected. The very remarkable fact recently brought to our notice by 

 Sir James Ross, as one of the results of his memorable voyage, that the 

 mean height of the barometer is nearly an inch less in the latitude of 

 75° S. than in the tropics, presses the consideration of this point upon our 

 notice; for it is either explained by the diminution of the vapour consti- 

 tuent in the higher latitudes, which diminution appears very nearly to 

 correspond to the decrease of barometric pressure observed by Sir James 

 Ross, or it is a fact unexplained, and I believe hitherto unattempted to 

 be explained, on any other hypothesis, of so startling a character as to 

 call for immediate attention. 



Second Supplement to the Catalogue of the Birds of 



Southern India, by T. C. Jerdon, Esq. 



Madras Medical Establishment. 



A considerable addition to the Ornithological Fauna of 

 Southern India, and a few important corrections form the 

 present article. Those species which are introduced here 

 for the first time as inhabitants of the Peninsula, are marked 

 with an asterisk. 



* No. 1. bis — Vidtur Indicus, Scopoli and Latham — not of 

 Sykes', nor of Jerdon's Catalogue— V. tenuirostris, Hodgson. 



This large species has been hitherto overlooked by me. 

 Mr. Blyth appears to think that V. Indicus Temm. is a 

 synonym of V.f ulcus, to which he now refers my V. Indicus, 

 and that V. Imperialis T. is a synonym of the present bird. 

 From the dimensions however assigned to V. Imperialis, viz. 

 40 inches (French measure) I am inclined to believe that 

 Temminck's Indicus refers to the same bird as that of Scopoli 



