210 Biographical Memmr of M. Haiiy. 



miliarized them with difficulties which the force of habit ren- 

 dered them now unable to perceive. It was on account of ha- 

 ving learned these sciences at a later period, that M. Haiiy 

 viewed them in a different light. The contrasts, the voids in 

 the series of ideas, made a vivid impression upon a strong mind, 

 which, at the period of its full vigour, entered all at once upon 

 a new study. He was deeply astonished at the constancy exhi- 

 bited in the complicated forms of flowers, of fruits, and of all 

 the parts of organized bodies, and did not conceive that the 

 forms of minerals, which were much more simple and in a man- 

 ner all geometrical, were submitted to similar laws ; for at this 

 period there was not even known the kind of semi-approxima- 

 tion which Rome de Lisle proposed in the second edition of his 

 Crystallogrofhie^. How, said M. Haiiy, should the same 

 stone, the same salt, shew itself in cubes, prisms, and needles, 

 without their composition changing an atom ; while the rose has 

 always the same petals, the acorn the same curvature, the cedar 

 the same height and the same developement ? 



It was when he was filled with these ideas, that, examining 

 some minerals along with one of his friends, M. Defrance, a 

 teacher of arithmetic, he had the fortunate awkwardness to let 

 fall a fine group of calcareous-spar, crystallized in prisms. One 

 of these prisms broke in such a manner as to shew on its frac- 

 ture, surfaces not less smooth than the external, and which pre- 

 sented the appearance of a new crystal, entirely differing in 

 form from the prism. M. Haiiy picked up this fragment : he 

 examined its surfaces, their inclinations and angles. To his 

 great surprise, he discovered that they were the same as the 

 rhomboidal or Iceland-spar. 



A new world seemed at the moment to open itself to him. 

 He retired to his cabinet, took a piece of spar crystallized in 

 the form of a hexahedral pyramid, commonly called dogs tooth 

 spar, broke it, and found still the same rhomboid as in Iceland 

 spar. The fragments which fell from it were themselves small 

 rhomboids. He broke a third crystal, one of the kind named 

 lenticular. It also shewed a rhomboid in the centre, and the 

 small fragments were of the same form. 



• It only appeared in 1783. 



