343 On a MINERAL supposed to be 



they entertain for the talents and accuracy of the celebrated 

 Hauy, may induce them to think his obfervations require no 

 concurring teftimony j and, on the other hand, the pupils of 

 the German School, confider no mineral deferring a place in 

 their fyftem, till it has been examined and clafied by their illu- 

 ftrious mafter, whofe authority will be handed down by them 

 with equal refpect to poflerity. 



It is unnecefTary to occupy the time of the Society, in gi- 

 ving a comparative view of the different defcriptions of the 

 Gadolinite. I fhall only notice a few prominent features. 



It is defcribed by every one of the authors, as poflefling a 

 fpecific gravity of upwards of 4, and as acting powerfully upon 

 the magnet. This laft character is noticed by Profeffor Jame- 

 son, in the nrft account he gives of the gadolinite ; but in the 

 fecond it is omitted, along with fome others. Klaproth takes 

 no notice of its magnetic power, but ftates the fpecific gravity 

 at 4.237. 



The French writers defcribe the colour as black and reddifh 

 black. The German as raven or greeniih black. Theie varia- 

 tions, with feveral others which may be obferved on referring 

 to the different authors, fhew that fome incorrectnefs muffc ex- 

 ift. Bat the molt remarkable of all is, that the gadolinite, if 

 'ever magnetic, is not always fo ; for the fpecimens in the poflef- 

 fionof the Count de Bourn on are not, nor, as he informs me, 

 are any that he has ever Teen. It is therefore reafonable to 

 conclude, that magnet ifm in the gadolinite may depend on 

 accidental caufes. 



The following is the defcription of the fojfil, which I fup- 

 pofe to be that iubftance in a cryftallifed ftate; % although no- 

 thing fhort of analyfis can afford indifputable teftimony of the 

 identity of any mineral fo little known. 



Specific 



