THE 



EDINBURGH 

 JOURNAL OF SCIENCE. 



Art I. — Specimen of the use of Notation in the Analysis of 

 Crystalline Forms. By the Reverend W. Whewell, Tri- 

 nity College, Cambridge. Communicated by the Author. 



THE notation by which the faces of crystalline forms shall be 

 designated, is, I believe, among persons who have paid an 

 imperfect attention to the subject, looked upon as a matter not 

 of great importance, nor offering any decisive principle of se- 

 lection with respect to the different systems which have been 

 proposed. It is probably taken for granted by most, that 

 such a notation can only answer the purpose of registering the 

 mode of derivation of crystalline faces in a manner easily un- 

 derstood and recollected ; and that, therefore, simplicity and 

 symmetry are the only merits which it can aspire to. This is, 

 in fact, the case with respect to Hauy's notation ; and though 

 that system might perhaps be improved and extended, it could 

 hardly be made subservient to any ulterior object. 



If, however, we have a notation which indicates, by means 

 of geometrical or arithmetical considerations, the law by 

 which planes are derived, these indications may be used in 

 finding the relations of the planes to one another, and the 

 angles which they make. Such a notation is that of Weiss, 

 which differs very little from a system which I had proposed 

 in the Philosophical Transactions, (Part i. 1825,) without 

 being aware that any similar method had been elsewhere 

 brought forwards. And by means of either of these systems* 

 we may, from the designation of the planes of a crystal, de~ 



VOL. VI. NO. I. JAN. 1827. A 



