MINERALOGICAL SYSTEMS, 33 



Mr. De L'llle terminates the introdu6lion to his work by De rifle's pro- 

 certain axioms, as he ftyles them> the 2d and 16th are asfol-^"^ axiom* 

 low: , 



*' II. Every angular polyhedron, or every cryftallized fub- 

 ftance is a salt in the mofl: extended acceptation of that 

 terra/' 



" XVI. Every faline fub^ance whofe confiituent parts are 

 perfectly faturated and combined affefts the cubic form, or its 

 inverfe the octahedron; whereas the falts which are not neuter, 

 or whofe conftituent parts are not exa6lly combined, affedt' 

 either the prifmatic or the rhomhoidal forms. '^ 



I need fcarcely obferve that, to treat thefe axiofils ohly as 

 doubtful, would be treating them kindly. The other axioms 

 are matters of fad, from which he draws no confequence, and 

 indeed it would have been difficult for him to have drawn any. 



The Abb^ Hauy does not undertake to prove generally, that Hauy'sexhlbl- 

 among the different cryftafline forms of the fame fubftance, one '^'o" <>f '^he pri- 



f xi • .1 • •.• 1.1 1 .1 . • ■>.' r mitive form in 



or them is the primitive; but he produces that primitive form cryftals, 

 from each cryftal, which is always fimilar in fimilar fubftances. 

 He demonftrates it analytically and fynthetically ; by an ana- ^y analyfis and 

 lyfis which might be called mineralogical analyfis, and pointed fynthefis. 

 out by nature herfelf : By a fynthetis hitherto the property of 

 mathematicians, but here fupported by the general laws which 

 bis analyfis has revealed to him. The conftant accord found 

 between this fynthefis, and daily obfervation is a proof of the 

 exadnefs of his method. 



Two fa6ls were the foundation of his theory : 1 . In all times Fundamental 

 jewellers and lapidaries have remarked that flones are more ^^*^^* '-Cry- 

 calily cut in fome certain directions than in others. 2. Who- in certain di- 

 everhas been in the habit of feeing natural cryftals muft have *"^'^ions only j 

 obferved, that when their forms are well determined, they are daries^are ^rigbt* 

 always terminated by plane furfaces. Thus, fays the Abb^, lined or plane. 

 ** thofe foft outlines, and that roundnefs fo frequent in the ani- 

 mal and the vegetable kingdom, where they are inherent to 

 the organization, and contribute even to the elegance of the 

 forms, indicate on the contrary in minerals a want of per- 

 fedlion. The charaderiftic of true beauty in minerals is the 

 ftrait line, and it was with truth that Rom^ de L'Ifle declared 

 that line to be the peculiar property of the mineral kingdom." 

 The firft fad fuggefted the mineralogical apalyfis, and the fe- 

 cond furniflied him with the laws on which he grounded his 

 fynthefis. 



Vol. IX. — September, 1804. D Enquiries 



