465 Charcoal- Fire. 



therto mistaken for greenstone. This place is of easy access, 

 both by sea from Mull, and from the interior by means of the 

 Moidart and Airdnamurchan new roads. 



We mav terminate these remarks by sug2,"esting to mineralo- 

 gists the necessity of examining more minutely into the supposed 

 greenstones of the trap family. There is reason to expect that 

 among these Augit Rock, also described in the same memoir, 

 at Sky, will be found to occupy the place too often assigned to 

 greenstone. Mineralogists have for some time remarked, that 

 augit was found in trap rocks ; but the author above mentioned 

 has found it so prevalent, where formerly overlooked, or con- 

 founded with the greenstones containing hornblende, that he 

 has been induced to designate this member of the trap family 

 also by an appropriate term. It forms a large tract on the 

 north-east coast of Sky ; and it seems moreover to constitute 

 nearly the whole trap formation of Rum ; besides which, we un- 

 derstand that he has traced it in many other parts of Scotland. 

 It is composed of augit and felspar^ both of these minerals being 

 subject to considerable variations, and the compounds therefore 

 presenting a great variety of aspects. When the augit is green 

 and the felspar glassy, as in some parts of Rum, the rock is easily 

 recognised ; when the former is black, and the latter of the com- 

 pact kind, it is more difficult to distinguish it from ordinary 

 greenstone. When extremely fine, it forms a rock not to be di- 

 stinguished from basalt by mere inspection. We expect a fuller 

 account of this important rock from the author, and of the way 

 in which it can, under all its aspects, be distinguished from com- 

 mon greenstone. The utility of the name will be apparent to all 

 who know the power that names possess in natural history of 

 directing attention to the objects of its pursuit; and there may 

 also be pointed out an important and new analogy thus proved to 

 exist between the traps and the lavas of modern volcanoes, of 

 which augit, and not hornblende, has also been recently shown to 

 be a principal constituent. 



CHARCOAL-FIRE. 



Notwithstanding the numerous accidents tirising from burning 

 charcoal in close rooms, a coirespondent assures us, that he, as 

 well as several of his friends, to whom he has recommended it, 

 has experienced almost immediate relief from cough and catarrhal 

 affections by sitting a few hours in his library with a chaffing- 

 dish of burning charcoal near his feet. He has found this prac- 

 tice so effectual a check to the effects of cold during the winter 

 seEison, that he can assuage even a violent catarrhal cough in 

 the course of a single day. It has even relieved persons with 

 weak lungs, and who are consequently subject to coughs during 

 the continuance of cold weather .or easterly winds. 



MR. 



