574 Correspondence. 



every 80 or 100 feet of perpendicular descent beyond this limit, we gain 

 1° Faht. which ratio of heat would render the hardest substances fusi- 

 ble at little more than 300 miles of descent, and thus shewing that our 

 earth is a mere crust surrounding a vast globe of liquid fire. The ar- 

 guments pro and con have been ably discussed by many authors, so that 

 we need not allude to them at present. We must now conclude our 

 notice, but shall probably take another opportunity of examining Dr. 

 Lord's papers further. 



As we were just finishing this article, the melancholy intelligence 

 of the death of Dr. Lord reached us. Our remarks we send for pub- 

 lication, in order that the attention of others may be drawn to the 

 subject. In Dr. Lord, the Honorable Company have lost an able, 

 zealous, and accomplished officer, whose talents promised to have raised 

 him, ere long, to a most prominent place. Some of his actions may 

 have been condemned, and they may or may not have been injudicious 

 for aught we know, but in what place, in what society, will you find it 

 otherwise ; a talented, bold, and enterprising officer, raised by merit, is 

 always exposed to the shafts of envy. To the medical profession of 

 India, Macneil and Lord, in these stirring times, form bright ornaments, 

 and a beacon, as it were, by which others may mark out their career, as 

 in them we have examples of meritorious service receiving its due re- 

 ward. If however Dr. Lord's career has been but short, it has been 

 brilliant, and his death though sudden, has been honorable. To him 

 the scientific world are deeply indebted, seeing that, until he visited 

 those countries, their structure was quite unknown. From, however, 

 the short time that he was there, and the important duties he had to 

 fulfil, he has still left a vast field to be explored, and whoever enters 

 on the investigation with the same energy, resolution, and enthusiasm, 

 cannot fail to be amply rewarded for his trouble. 



October, 1840. M. A. S. B. 



$Lt\xs infiltration*. 



Edinburgh New Philosophical Journal, July, 1840. 



In an excellent article in the number of the Edinburgh 

 Philosophical Journal, July 1840, on Phenomena necessary 

 to be acquainted with in Preliminary Mining, Professor Mohs 

 states that mining districts usually lie between two or more 

 mountain groups, or constitute a portion of them. A know- 



