16 REPORT— 1839. 



Hence it appears that the mean temperature of 1834 was 67'3 Fahr., 

 that of the hottest month (April) 74*4', that of the coldest month (Dec.) 

 62*3 ; the mean maximum (April) 82*2, and the mean minimum 

 (Dec.) 56*2. The mean variation was greatest in April, 15*5, and 

 least in September, 2*8 ; and the mean variation for the year was only 

 9*5. The fall of rain was prodigious, being equal to 25 feet 2 inches, 

 and this enormous mass of water fell almost entirely in the months of 

 June, July, August and September. General Lodwick, late president 

 at the court of Sattarah, who transmitted to me the official register, 

 says, " I send to you a copy of Dr. Murray's meteorological table. 

 The inches of rain are no less than 302*21. This will astonish the 

 philosophers, but it would do more than astonish them, had they the 

 opportunity of seeing and hearing the rain fall in torrents through a 

 dense fog or mass of clouds which lie upon the ground for perhaps 

 six weeks together, with a temperature by no means cold, and with little 

 variation." The excessive fall of rain along the line of the Ghats does 

 not seem to be incompatible with health, for the military detachment 

 stationed permanently at Mahabuleshwar is not characterized by any 

 unusual sickness ; and the statistical returns of the population on the 

 hills are as healthy as those of the table-lands to the eastward. It now 

 remains to notice some striking facts on the western side of the pen- 

 insula. The quantity of rain that falls differs exceedingly between 

 the coast, the Ghats within fifty miles of the coast, and the table- 

 land eastward of the Ghats. The mean at Bombay is 80-69. Dr. 

 Murray shows a fall in the hills, at the elevation 4500 feet, of 302 

 inches, and my records at Poonah give a mean annual fall of 23*43 

 inches. The solution of the causes of the anomalous fall of rain does 

 not offer any considerable difficulties. The enormous mass of vapour 

 taken up from the Indian Ocean on approaching India, does not appear 

 to have its upper surface at a greater elevation than five or six thousand 

 feet, while the stratum is of great thickness ; and I can bear testimony 

 to its lower surface being below fifteen or eighteen hundred feet. The 

 temperature of the air over the equator is necessarily very high, and 

 its capacity for the support of aqueous vapour is proportioned to its 

 temperature. The vapour is converted into rain, as it is driven into 

 air of lower temperature ; and, as the temperature gradually lowers 

 proceeding to the north, and approaching the land, it follows, that out 

 at sea, and along shore, with equal supplies of vapour, a less quantity 

 of it would be converted into rain eastward. With respect to the pro- 

 digious fall at Mahabuleshwar and along the Ghats, it may be accounted 

 for by the supposition that the monsoon vapour being of low elevation 

 and high temperature, is driven against the mural faces, and up the 

 chasms of the Ghats, into higher regions, and into a colder atmosphere, 

 and is thus immediately converted into rain. The paucity of rain forty 

 or fifty miles eastward of the Ghats, results from the comparatively 

 small quantity of vapour which escapes from the cold belt of air 

 through which it is forced to pass in the hills. 



