98 Extract from Dr. RoyWs Address. [March, 



accumulate ; in the hills, on the contrary, some power must exist which 

 carries off a portion of the heat as rapidly as it is communicated : this 

 power is the breeze which is found daily to set in from the plains towards 

 the hills, which commences about 10 A. m., (the very time after which 

 so little increase takes place in the temperature,) and passing over 

 the top of the range prevents the accumulation of any heat. It 

 might appear, however, that as the atmosphere is heated to so high 

 a degree in the subjacent plains, the effect of a breeze setting in 

 that direction would be rather of a heating than that of a cooling 

 nature ; and it would be so, but the air as it ascends becomes less 

 dense, and in proportion to this diminution of density is its capacity 

 for heat increased, so that it is enabled to absorb all that which was 

 sensible to the feelings, or was observed by a thermometer, in the 

 plains ; and thus, when it arrives at the top of the range, it feels cool and 

 refreshing. At night a similar but more gentle breeze sets in from the 

 hills towards the plains, and the two may with the strictest justice be 

 compared to the land and sea breezes of the coast. 



Vegetable Impressions of the Coal Strata. 



On my way to Calcutta by dak, 1 visited the coal mines of China- 

 kuri and Rdniganj, and procured a large collection of vegetable im- 

 pressions, but I have not yet had time to ascertain whether there be any 

 thing new among the number, though I am inclined to think, that the 

 straight and striated unjointed reed was not among the specimens I saw 

 with Dr. Falconer or the Rev. Mr. Everest. In travelling along the 

 road after collecting these impressions, it struck me, that as the theory 

 of the formation of coal supposes the existence of vegetables in swamps 

 or jhils of a former period of the world, at which time many phenomena 

 indicate a high degree of temperature, considerable assistance might be 

 derived in confirmation or refutation of this theory, by examining the 

 plants which now exist in the jhils of India, and comparing them with 

 the vegetable impressions which distinguish the coal bason. The subject 

 would lead me into too much detail now, but I hope to be able to 

 follow it up at some future period. It may be cursorily remarked, 

 that all the peculiarities stated by Mr. Conybeare as marking the 

 vegetation of coal fields, may I think, be observed in the vegetation 

 which now floats on the surface of the jhils round Calcutta. Their 

 peculiarities are, 1, great length of stem; 2, deficiency of bark; 3, 

 want of consistence in the woody fibre ; 4, striated appearance of stem ; 

 5, its frequently jointed nature, with great inequality in the length of 

 the joints ; and 6, the absence or smallness of roots. The Mentha 

 verticlllata displays itself many of these peculiarities : a resemblance 



