220 



Frafture. 



Composition. 



ON STONY AND METALINE SUBSTANCES, &C. 



" des noeuds et des petites veines, qui Ie parcourent en tout 

 " fens : la couleur des pyrites eft dore* ; le poli leur donne un 

 a ^clat d'acier, et, expofees a l'atraofphere, elles terniffent 

 " et bruniflent. On diftingue de plus, a Poeil mid, de la mine 

 f « de fer grife, (Scailleufe, non fulfureufe, attirable a l'aimant, 

 •' diffoluble dans les acids, peu oxid£, ou s'approchant beau* 

 " coup de l^tat meHallique. 



" La caflure eft irr^guliere, grenue, d'un grain un peu 

 " ferr£ : dans l'interieur on voit de tres petites fentes. Elle ne 

 " fait pas feu au briquet : fa contexture eft ii lache quelle fe 

 y laifle entamer au couteau. Enlapilant, elle fer^duit aflez 

 " facilement en une poudre grife bleuatre d'une odeur terreufe. 

 *' Quelquefois il fe trouve de petits criftaux de mine de fer, 

 " qui reiiftent plus aux coups du pilon." 



The fpecific gravity of the piece in ProfefTor Barthold's 

 pofleftion, was 3233, diftilled water being taken at 1000. 



The analyfis of Mons. Barthold, of which I mall alfo 

 have occaiion to fpeak hereafter, gave in the 100. 



Sulphur 

 Iron 



Magnefia - 

 Alumina 

 Lime 

 Silica - 



2 

 20 

 14. 

 17 



2 

 42 



97 



From the external characters, and from his analyiis, the 



Profelfor confiders the ftone of Enfifheim to be argillo-ferru- 



ginous ; and is of opinion that ignorance and fuperftition have 



attributed to it a miraculous exiftence, at variance with the 



firft notions of natural philofophy.* 



Sir W. Hamil- The account next in fucceflion is already printed in the 



ton's account of Tranfadions of the Royal Society ; but cannot be omitted, as 

 ftones that fell . . ' J J ' T , '. 



during a thunder it immediately relates to one of the lubltances 1 have examm- 



ftorm. e j # J allude to the letter received by Sir William Hamil- 



ton, from the Earl of Briftol, dated from Sienna, July 

 12th, 1794. " In the midft of a moft violent thunder-ftorm, 

 " about a dozen ftones, of various weights and dimenfions, 

 " fell at the feet of different perfons, men, women, and 

 " children. The ftones are of a quality not found in any part 



* See Journal de Phyfique. Ventose, An. 8. p. 16$. 



of 



