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4 6 



T H 



NAT 



R A 



H 





T 



« 



R Y 





i °. TALCUM 



Talk. 



. Diaphanum lamellis tenuijjimis. 



Izing glafs. 

 2 . Diaphanum lamellis craffioribus rhambeis. 



Scaliola. 





. Particulis ad angidwn acutum ftriatis. 

 (_ 4 . Fibris radiatis e centra radiantibus. 



fparent, and though compofed of many Iamin: 

 an eafy paffage to the rays of light : the productions of this kind are 

 fifiile into horizontal and traniparent flakes \ and bear the action of the acid 

 irate with eafe, but yield more or lefs, though never perfectly to the fire. 



L. S. N. 



Talk is generally 



yield 



ways 

 every 



t 











2°. GYPSUM 



Gspfe. 





1. Pellucidum decaedro rhombeum. 



2 . Pellucidum triquetrum> adfummmn pyramidatu 



3 . Pellucidum pentagonum, adfummum pyramidat 



I 







The Gypfe is not only tranfparent, but is commonly found of fome regular fo 



approaching upon the rhomboide. It yields readily to the fire, but does not ferment 

 with acids in any flate. 



There are other produ&ions of this nature that are flill more compound and opake; 

 and though, generally, of no firm cohefion, feldom yield to the fire, but never to the 

 acid when pure and alone : it is not, however, uncommon to find them mixed with 

 a foreign fluor, or other particles on which you may obferve the fire, or the acid, to a<3: 

 occafionally. I fhall range the fpecies of this clafs in the following order, viz, 



} Particulis impalpabilibiu argenteis, 



Particulis impalpabilibus_ aureis. ^ 

 Particulis fquamojis fparjis. 



Particulis fubprifmaticis inter cujfantibus. \ L. S. N" 

 Solida nigra Juperficie atro glabra. 



MICA 



Mica, 





The mica is a terrene fubflance of a fparkling appearance, and feemingly compofed 



of thin, fmooth, fubdiaphane and fquamofe parti 



are feldom of any firm 

 with equal eafe 



the productions of this kind 



though they bear the a&ion of the fire and the acid 



2°. ASBESTOS. 



Jfbejlos. 



i. 



2 



2: 



Soli diuf cuius Ji/Jilis. 

 Solidiufculus Jlexilis . 



t 





L. S. N. 



3 . Membranaceus Jlexilis. 



The Afbeftus is of a true terrene nature, and a fibrous interwoven 



bears 



the action of both the fire and the acid with equal eafe 





mj 







I. 



Fibris Jilijormibus Jlexilibus 



3°. AMIANTUS | 2. Fibris angulatis rigidis op 



Amiante 



< 



I 



3. Fibris fragilibus diaph 

 \±. Fibris mollibus pappofis 



L. S 



•i 



mm n* 



The Amianth is diftinguifhed from the foregoing only by the fi mple longitudinal 

 difpofition of its fibres ; it bears the adtion of both the fire and the acid equally. 





/ 





f I . Fibris fubdiaphanis oblique difpoJitis x 

 4°.TRICHERIUM 1 2. Fibris longitudinalibusfubdiaphanis. 



1 3 . Fibris radiatis fubdiaphanis. 





The 







