246 NICOLAUS STENO 



the bases of triangular planes, since traces of striae appear in 

 them parallel to the bases. 



That in the case of copper, angular bodies are formed in the 

 same way that has been mentioned in the case of' the crystal 

 and iron, is inferred from those bits of copper which you ^ pre- 

 serve among the curiosities of nature,^ but since the abundance 

 of the matter has filled all the interstices of the bodies, it is 

 difficult to ascertain the original form of the bodies. And pre- 

 cisely the same is true of the angular bodies of silver sent to 

 you from Germany. 



CONCERNING THE DIAMOND 



Concerning the diamond, the same thing is inferred touching 

 the place and manner of production which is inferred from the 

 crystal, namely: 



1. That diamonds have been produced in a fluid enclosed in 

 p. 49. the cavities of rocks, although a distinguished writer on India 



attempts to prove that diamonds are again produced in a certain 

 period of years, in the earth from which they have once been 

 dug.^ 



2. That they have been produced from a fluid by the 

 accretion of diamond matter. 



3. That in their production the workings of both the at- 

 tenuated permeating fluid and the surrounding fluid must be 

 taken into account. 



For the rest, as regards the form of diamonds, it varies 

 greatly, since some are bounded by eight planes, others by 

 nine,* others by eighteen, others by twenty-four planes; and 

 among these most of the planes were striated, while some were 

 also smooth. Although some diamonds might be angular, 

 they nevertheless could have some surfaces curved rather than 

 plane. 



^Ferdinand II. See p. 205. 



^ Stenb refers to the collection in the Pitti Palace. See p. 182. 



^ Maar (op. cit., Vol. II, p. 338) observes that Steno may have had in mind P. de Rosnel's 

 Le Mercure Indien (Paris, 1667), Seconds parte, livre premier. Chapter II, p. 12 : "Monardes 

 en son livre . . . remarque que les grands diamants prennent d'ordinaire leur naissance de la 

 partie inferieure de la mine, et que les petits prennent la leur de la partie superieure." 



■> Not a regular form of diamond but doubtless due to the disappearance of certain faces. 



