INTRODUCTION. xxiti 2. As orydtognofie is the ground work of mine- Oryaogno- ralogy, a knowledge of it mult neceffarily precede fis of miiie- that of the other dodtrines. This is the reafon why^' 087 ' it is to occupy the early part of this work. I mult re mark, however, that it is not purely orydtognoltic, or I have added to the defcription of each mineral, lts c ^emical characters, conllituent parts, geognoftic and geographic Situations, and a few notices refpedt- mg its ufes. 3. An arrangement to be corredt flrould have but ar . one objedt for its bafis; for when feveral are affumed n,n g e,lli:ut - it fails completely in accomplilhing its purpofe: it is a o indifpenfably necelfary in arranging naturat bo- 'es, that none which fall within the bounds of the .* em be om 5wed. Many mineralogilts, by affum- as the bafts of their fyftems not only the natural phi cl C fimatio ^ ^ chemica } compofition, geogra- anH K r ’• 3 economical ufes of minerals, p ?T g ,he volcmic °'i«r a 1 t pr ° ' > ha,e rendered their fyftems mi (table tem ! p° ln Pj te ‘ Ur e Wernerian orydtognoltic fyf-Bafisrfth. Sf,c2 m C °"/ 0rmi,y ' vi,h ,h ' IW “ mler of^S- anccs / j-«■ 1C 1S oun{]ed foleI y on the natural alii• flJ- on wha! a '^f rcnces obfervable among minerals. But quality ^ dCpend ? Werner anfwers on the conftituent pTrtl’ ^ m ° de ° f C ° mbinat5on of the have ohil/J | dUy ’ Broc!lant > anJ other mineralogifts objeai«™ ^es m n \° thC Wenierian that k ar-^ Cra to gcther which are completely dif ferent