•1'24> Mr. Brooke's Additional Remarks on Isomorphism. 



candens. M. (white trailing hispid) : 



a. minus :ioYi\s magis candentibus. Flores (duos solum 

 vidi) terminales in ramulis lateralibus, solitarii parvi 

 albi concinni antemeridiano, mox erubescentes, deni- 

 (]iie la?te rubicundi. Ca?teri ordinarii. 



Floret Junii mense. G. H. ^2 • 

 )3 viridius, duplo majus omni parte, foliis viridioribus 

 floribus (horum 2 solum vidi) albis seu niveis pulchri- 

 oribus mox erubescentibus, denique alte rubicundis, 

 antemeridianis. 



Flo7-et Septembris mense. G. H. ^ . 



Obs. 3. Rami prostrati hujus speciei ex eorum nodis 

 valde radicant, uti Fragraricc sarmenti. 



L V. Additional Remarks on Isomorph ism. Bij H . J. B rooke, Esq. 



F.R.S. L.S. 4- G.S.* 

 TN the appendix to a work just published by Dr. Daubeny 

 -*- on the Atomic Tlieory, some observations are inserted re- 

 lative to a paper of mine on Isomorphism, inserted in No. 57 

 of this Journal. 



Upon these observations I shall at present only remark, 

 that they contain two paragraphs upon which I am desirous 

 of immediately setting myself right with Dr. Daubeny and the 

 readers of his work. 



Dr. Daubeny says, "It seems impossible to apply the [theory 

 of mixture of foreign matter] to the garnet species, neither has 

 Mr. Brooke attempted to do so." 



What mineral is it, I should first be disposed to inquire, 

 that is to be designated by the name of Garnet? It is not 

 denoted by its crystalline form, for that is common to a 

 variety of others ; and there is no very apparent reason why, 

 among the substances which, chiefly on account of their si- 

 milar forms, have been included under the supposed garnet 

 tribe, there should not be some, which, on account of their 

 chemical differences, do really constitute distinct species. 

 To enter, however, upon an investigation of this question 

 would require a knowledge of the chemical constitution of the 

 matrices or rocks in which the several varieties have been 

 found ; — a point upon which scarcely any correct information 

 can be collected from the published works on the subject. 

 And probably on reconsideration Dr. Daubeny will be of 

 opinion, that the garnets are, from the class of forms to which 



* Communicated by the Author. 



they 



