294 



The phofphoref- 

 ceace of tremo- 

 litc being ad- 

 mitted to arife 

 from intetfperfed 

 ca: bonate of 

 lime, will ac- 

 count for the 

 differing obfer- 

 vations of au- 

 thors. 



Though the 

 phofphorefcence 

 of tremolife 

 cannot b*. ad- 

 mi ttedas fpeci fie, 

 yet the f.iriiity 

 with which this 

 very hard mine- 

 ral is crulhed 

 by preflure with 

 the hammer and 

 its elaftic refift- 

 ance, are pecu • 

 liar ipecific cha. 

 rafters. 



Tremolite is 

 found in Scot- 

 land, at Mount 

 Vefuvius, and 

 in Bengal. 



Defcriptinn of 

 the tremolite of 

 Scotland. 



OBSERVATIONS ON THE TREMOLITE. 



When it is once admitted that the tremolite is phofphorcf- 

 cent only in proportion as this property is contained in the 

 carbonate of lime interpofed in its fubftance, the variations 

 which fome authors have found in its phofphorefcence, will 

 be eafily accounted for. It muft, for example, be the more 

 eafily obtained by friction, as the hardnefs of this ftone is lefs 

 confiderable ; becaufe the friction, by breaking its furface, 

 will fucceffively arrive at the interpofed particles of carbonate 

 of lime. And hence it is quite natural that the fibrous varie- 

 ties fhould be more phofphorefcent than the others, and that 

 thefe fhould be the lefs fo in proportion as they are harder. 



As this character, which was reprefented as fpecific in the 

 tremolite, muft no longer be confidered as fuch, there is one 

 which has been overlooked, and which, in my opinion, ought 

 to be added to thofe which have been already obferved in it ; 

 I mean the great facility with which, notwithstanding its 

 hardnefs, which, in the pureft fpecimens is fuch that it eafily 

 cuts glafs, it is cruihed by the mere preflure of the hammer, 

 and the kind of flexibility which it then exhibits. If, in break- 

 ing it, the preflure be moderate, the cryftals of tremolite di- 

 vide, pretty generally, according to the length of their prifms, 

 into fmall fibres, which are frequently as fine as thofe of the 

 amianthus, to which, in this ftate, they have much refem- 

 blance. We may then even increafe the preflure without 

 breaking the fibres, which in this cafe afford by their refi fi- 

 ance the fame fenfation as is felt from a flightly elaftic body. 

 This effect, as well as the reduction of the tremolites into 

 fmall fibres, is more diftinct the lefs pure the mineral. Both 

 properties however are obferved, but in a much lefs degree 

 in the pureft tremolites, and confequently in thofe whofe 

 hardnefs is the moft confiderable. 



With a view to add as much as poffible to the knowledge 

 already acquired refpecting this fubftance, I fhall add to the 

 lift of places which have been indicated as the native coun- 

 tries of the tremolite, Scotland, Mount Vefuvius, and Ben- 

 gal. Mr. Greville's rich cabinet in London contains fpeci- 

 mens from each of thofe different places; a defcription of 

 thefe will probably be acceptable to mineralogifts. 



The tremolite of Scotland is in the fibrous ftate, its fibres 

 being very fine and clofe, part of which is difpofed in diver- 

 gent 



