98 



Remorcfl to 

 Parij, and ex;a« 

 xnmed. 



Its fi^rc 



Col©ur, 



Has blebs. 



These marks 

 doubtful. 



Sped. grav. not 

 exami/ied. 



Hardness. 



liUPPOSED ANTIQUE EMERALD. 



At length this vessel having been transferred to the impe- 

 rial library, the Institute was requested by the ininibter to. 

 ascertain its quahty ; and Haiiy, Vauquelin, and Guyton, 

 were accordingly appointed to examine it. What follows is 

 the substance of Mr. Guyton's report. 



Its diameter, from one angle to another, is 39*143 cent. 

 [15 in. 2 1. Eng.], its depth within 12*357 [4 in. 8 1.], iU 

 height, including the foot, which is of the same piece, 1 6*476 

 [6 in. 4l.]. It has two handles, likewise formed in the same 

 piece, without any appearance of having being joined to it 

 after it was made. One of these is broken. The bottom ap- 

 pears to have been wrought on the wheel, so as to form a cir- 

 cle of small cavities, whence issue six rays, corresponding to 

 the angles. PI. Ill, fig. 3, is an exact representation of the 

 bottom ; fig. 4 shows it standing on its foot, and fig. 5 in- 

 verted, with the position of its handles, which are placed so 

 as to be concealed, yet in a manner to be taken hold of ea- 

 sily. 



The colour of the dish is an olive green, duller than that 

 of the peridot, with something of a greasy cast, that brings 

 it nearer to the plasma of the German mineralogists, than 

 to the green emerald of Peru, or the bluish emerald, or 

 aqua marina, of Siberia. Its transparency participates of 

 this tint. 



On holding it up against the light, a bleb about 2 millim. 

 ['78 of a line] is distinguishable near the centre, and farther 

 off some very small blebs. 



It would be difficult from this description to infer the na- 

 ture of its substance, since it is now well known, that the 

 colour of gems of the same species varies considerably, and 

 that rock crystals exhibit blebs interiorly, which we cannot 

 always distinguish with certainty from those in glass. 



We could not conveniently examine its specific gravity, 

 on account of its size : and besides it would have been to 

 little purpose, as the specific gravity of the emerald does not 

 much exceed that of common glass, and is inferior to that of 

 a glass loaded with metallic oxides. 



We ascertained its hardness, however, which is a less 

 equivocal character of gems ; and found it very evidently 

 scratched not only by the emeralds of Peru and Siberia, 



but 



