J(J(5 Tnrallel of Home de VhUs ami 



ate matters of fact from which he draws no consequences ; 

 and indeed it would have been difficult for him to have 

 drawn any. 



' The Abbe Hatty does not undertake to prove, generally, 

 that among the different crvstalline forms of the same sub- 

 stance, one of them is the primitive. But he produces from 

 feach crystal that primitive form which is always similar in 

 similar substances. He demonstrates it analytically and 

 synthetically : by an analys is which might be called minera- 

 logical analysis, and pointed out by nature herself; by a 

 svnthesis hitherto the property of mathematicians, but here 

 supported by the general laws which his analysis has re- 

 vealed to him. The constant accord found between this 

 synthesis, and daily observation, is a proof of the exactness 

 of his method. 



Two facts were the foundation of his theory. 

 1st, In all times, jewellers and lapidaries have remarked 

 that stones are easier cut in some certain directions than in 

 others. 



2d, Whoever has been in the habit of seeing natural 

 crystals must have observed that, when their forms are well 

 determined, they are always terminated by plane surfaces. 

 if. Thus," says the Abbe, "" those soft outlines, and that 

 roundness so frequent in the animal and the vegetable king- 

 doms, where they are inherent to the organization and con- 

 tribute even to the elegance of the forms, indicate, on the 

 contrary, in minerals, a want of perfection. The charac- 

 teristic of true beauty in minerals is the straight line, and it 

 was with truth that Rome de ITsle declared that line to be 

 the peculiar property of the mineral kingdom." The first fact 

 suggested the mineralogical analysis, and the second furnish- 

 ed him with the laws on which he grounded his synthesis. 

 Inquiries on the first fact. 



1st, All crystals that can be split by means of instruments 

 offer to the view, if split in certain directions, plane and 

 smooth surfaces. If divided in other directions, the frac- 

 ture is rugged.' I use the word split, and not sawed or cut, 

 as the sections of the crystal are not to be obtained by slow 

 and continued efforts, but by sudden shocks. Patience, 

 dexterity* and habit enabled the Abbe to split a great num- 

 ber of crystals; in all he discovered plane smooth surfaces, 

 when split in certain directions, but when in other direc- 

 tions the fracture was always rugged and irregular. I re- 

 quest, sir, vour attention to this important fact ; it is fun- 

 damental, and the more important, as several persons of 

 Huick general information have neglected to attend to it, 

 1 anji 



