Cn a new Variety of Epidote. ftc 



Ihat it is infoluble in liquid mercury: this has been afcer- 

 tained by experiment. 



An exaft knowledge of the fpecific denfity of aro-ental 

 mercury, as well as of the proportions of its two component 

 principles, has fuggeftcd the idea of making fome refearches 

 m regard to the denfity of folid mercury. Chemifls have fet 

 out with the fuppofition that the moleculse of the two frietals 

 experience no dilatation nor penetration in combining : 

 knowing the fpecific gravity of filver = 10*4743, that of 

 argcntal mercury = 14-1192, and the ratio of the tw6 

 metals 4tj it \^'ill be found that the fpecific gravity of folid 

 mercury ought to be i6'2662. In the cafe of there being a 

 penetration of molecul3e,as is probable, the real denfity would 

 be fomcwhat lefs : on the otfier hand, if there be dilatation, 

 it will be found to be more confiderable. In a word, this 

 approximative reOilt ought the lefs' to be m.'glc(Sl;ed, as it is 

 probable that it will be always very difficult to attain direHly 

 to an eftimation perfectly exatt. :r\ 



VII. Extrad of a Nqiice,, iwid;mikeFreneh..]^atiphalIn.' 

 Jlitute, on a new Variety ofEpidoie. ^ jB;<.C>HAMPeaux 

 and Cressac, Engineers of Mines *. 



JL HE fubftance which 'fotnis'»^HeobJc£l; of this notice was 

 found in the primitive chain which traverfes the country ©f 

 the Grifons, and unites the mountains of St. Gothard to 

 thofe of the Tyrol. .'aj; , n ',:,>-, .. ,-. : ■ ,^ , 



It has always been foUnd^iWVited tb aVariiety. qf red garnet, 

 which Sauflure has defcribcd f as a particular fpccics under 

 the name of hyacinth de DifJ'entis. 'To complete the defcrip- 

 tion of this fpccies, he ^ives a fhorj. defcription .of the. fub- 

 fiance which forms the Uibjecl of this article, ,a,nd he gives 

 it the name of phreiiile, becuufe he thought he could dillin- 

 guith in it charaAcrs which brought it near to the phrenile 

 of Oifans. 



In this defcrlplion we fliall follow the method adop^d.by 

 profeflbr ilaiiy. ..,^_, . I," t '^ 



r.ffential Charaacr. 



Divifible in a direction parallel to the planes of a right 

 rhomboidal prifm, which form with each oth(;r angles .of 

 J14" 37' and 65r2(i'. ; . , , , , 1 . " 



• From x\\cJMmlMfi^mnfs, 'No, Cf. 

 ■f Voyai'c dans Ic'S Alpts, 5 1901. 



Vh^'ftea^ 



