tf 



ON THE DIOPSIDE. 



Rumination thrown upon vapours supposed to arise from the 

 J>ody of the comet. 



By the gradual increase of the distance of our comet, we 

 have seen, that it assumed the resemblance of a nebula ; 

 and it is certain, that had I met with it in one of my 

 swee]>s of the zones of the heavens, as "it appeared on either 

 of the days between the 6th of December, and the 21st of 

 February, it would have been put down in the list 1 have 

 given of nebulae. This remark cannot but raise a suspicion, 

 that some comets may h::.ve actually been seen under a ne- 

 bulous form, and as such have been recorded in my cata- 

 logues; and were it not a task of many years labour, I 

 should undertake a review of all my nebulce, in order to see 

 whether any of them were wanting, or had changed their 

 place, which certainly would be an investigation, that might 

 lead to very interesting conclusions. 



III. 



Remarks on the Diopsidc, a new Species in Mineralogy esta- 

 blished by Mr. Haiiy, comprising two Varieties found in 

 the Piedmontese Alps by Mr. Bonvoisin, and described in 

 the Journal de Physique for May, 1806, under the names of 

 Mussite and Alalite. By Mr. Tonnelier, Keeper of the 

 Cabinet of Mineralogy to the Council of Mines*. 



Di-covery of Jl HE naturalist, who is led by his zeal to researches ajt- 

 " ew . s,,bstant ; tended with much toil, feels himself well rewarded, if in 



ths best reward ' 



of the natu- his travels he be so fortunate, as to meet with substances not 

 rahst. y e |. j inown> Such discoveries he considers as the most valu- 



able recompense of his labours; and he deems it his duty, 

 to publish descriptions of the new objects, with which he 

 has enriched the field of science. Mr. Bonvoisin, a much 

 respected natural philosopher, member of the imperial aca- 

 demy of Turin and of the legislative body, has recently ex- 



This occurred p er jenced this satisfaction. Many celebrated naturalists had 

 toBonvoi-sm in ....... . , • 



the Piedmon- visited the Piedmontese Alps before him, and made known 



tese_Alp$. ^ us, among the subjects they have had opportunities of ob- 



• Journal des Mines, vol. XX, p. 65. 



serving, 



