198 Mr, Henwood on the Differences of Temperature 



300. Menispermum cordifoUum. 



301. MussL pai^adisaica. Plaintain 



302. Musa,? On Ghauts. 



303. Mimoss. pudica. 



304. ,, cinerea. 



305. ,, Arabica. 

 sive use as firewood. 



306. ,, scandens. 



307. ,, Sirissa. 



308. ,, glauca. 



309. ,, dulcis. 



{To be continued.) 



Babool tree; common; in exten- 

 On the Ghauts. 



Article VI. 



On the Differences of Temperature between the Granite and 

 Slate in the Cornish Mines. By W. J. Henwood, F.G.S. 

 London and Paris, Hon. M.Y.P.S., Assay Master of Tin 

 in H. M. Duchy of Cornwall. 



To the Editor of the Records of General Science. 



Sir, — Having, in an examination of the mines of this 

 county, made many observations, which, I think, clearly 

 show a difference in the temperatures of the granite and 

 slate, permit me a page of your valuable Journal for a brief 

 abstract of them. 



Granite. 



Depth. 

 Surface to 50 fathoms ; average 31 fathoms, 



50 „ 100 „ 

 100 „ 150 „ 

 150 „ 200 „ 

 200 and beyond 



79 

 133 



Slate. 



Depth. 



Surface to 50 fathoms ; average 35 fathoms, 



50 „ 100 „ „ 73 „ 



100 „ 150 „ „ 127 „ 



150 „ 200 „ „ 170 „ 



200 and beyond „ 221 „ 



These observations have been, in all cases, made on jetting 

 and running streams of water, immediately on their issuing 

 from the unbroken rock; a mode, which, I think, more 



