APPENDIX. 147 



Strontites and its compounds tinge flame, which barytes 

 does not. Laftly, thefe earths difagree in the order of their 

 attractions. 



From thefe confederations, it is concluded, that the mineral 

 is not aerated barytes. 



Sometimes the Strontian foflil refembles calcareous fpar ; yet 

 they efientially differ* in property and compofition. That from 

 Strontian is much heavier, and retains its fixed air with more 

 obftinacv in the fire. The incomparably greater folubility of 

 the pure earth in hot than in cold water, and the cryftalline 

 form it affumes, fufficiently diftinguifh it from lime, which the 

 difpofition of the nitrate and muriate to cryftallize, no lefs tends 

 to do. 



The quality of colouring flame does not ferve here as a cir- 

 cumftance of difcrimination, as Dr Hope has difcovered, that 

 muriate of lime alfo tinges the flame of a red colour, but in a 

 lefs vivid manner. Strontites further differs from lime in the 

 order of its attractions. 



No parallel is drawn between Strontian mineral and other 

 earthy bodies, as they have not the fmalleft refemblance. 



As the earthy bafis of the Strontian fpar poflefles remarka- 

 ble qualities, that are peculiar to it, and forms with acids com- 

 binations unlike thofe generated by the known earths, and dif- 

 fers from all of them in the order of its attractions, the author 

 of the paper concludes, that it is an earth fui generis, a. feparate 

 and diftinct genus, constituting the fixth Ample earth, to which, 

 as above mentioned, he gives the appellation of Strontites. 



Dr Hope afterwards details a long train of experiments to 

 eflablilh the order of the attractions of this new earth ; firft, 

 determining the order in which the principal acids attract it, 

 and then lhowing the place due to its attraction among thofe 

 of other fubftances for acids. The tables that are fubjoined ex- 

 hibit thefe attractions 



Dr 



