M. Dutrochet on Endosmose and Eocosmose. 317 



three of the neighbouring stratum only, one of which touches 

 by its flat surface, and the other two by their edges only. 



I am satisfied, however, that there are in the crystal strata 

 of this description, because in a piece weighing half a pound 

 it is divided in its whole length by the plane GHKL, which 

 appeal's from the prismatic colours diffused over the whole of 

 the plane, although the two pieces are still kept together.* All 

 this proves, then, that the composition of the crystal is such 

 as we have mentioned. To this I add one experiment more, 

 which is, that if we draw a knife in scratching upon any of 

 these natural faces, descending from the obtuse equilateral 

 angle, that is, from the point of the pyramid, we shall find it very 

 hard, while in scratching it in the opposite direction it is easily 

 cut. Thisfollows manifestly from the situation of the small sphe- 

 roids upon which, in the first case, the knife slides, while in 

 the second case it takes them below like the scales of a fish. 



I will not undertake to say any thing respecting the man- 

 ner in which so many small corpuscles are produced, all 

 equal and similar, nor how they are put into such a fine ar- 

 rangement ; whether they are first formed and then arranged, 

 or whether they arrange themselves as they are produced, 

 which seems to me the most probable. In order to unfold 

 truths so concealed, requires a knowledge of nature greater 

 than we possess. I shall only add, that these small spheroids 

 may greatly contribute to form the spheroidal waves of lights 

 (i. e. the unusual refraction of calcareous spar,) already sup- 

 posed, both of them being similarly situated, and having their 

 axes parallel. 



Art. XXII. — New Researches on Endosmose and Exos- 

 mose. f By M. Dutrochet. 



The experiments which I communicated last year to the Aca- 



* These are the faces of composition (and not cleavage planes), describ- 

 ed in the preceding paper. — Ed. 



•J- Read before the Academy of Sciences of Paris, 17th March 1828, and 

 translated from the Annates des Chimie, Fev. 1828, p. 191. See our last 

 Number, p. 103—112. 



M. Dutrochet has received from the Academy of Sciences of Paris, one 

 of the Gold Medals founded by M. Monthyon, for his discovery of En- 

 dosmose. — En. 



VOL. IX NO. II. OCTOBER 1828. X 



