"^j THEORIES OF CRYSTALLOGRAPHY. 



pepper-corn is'cut in two, we find it compofed of two coats* 



The outermoft brown ftirivelled coat is eafily feparated by 

 ileeping the pepper in water. The fecond coat is much 

 thinner and hghter coloured ; it does not feparate by macer- 

 ation. Beneath this coat is a thick zone of pale green mat- 

 ter, apparently ftarch united to oil. This is fucceeded by a 

 thin yellow zone, feemingly of nearly the fame compofition. 

 Within this is a fmall fpherical fpace, fometimes hollow, but 

 moft commonly filled with a foft white fubftance like the pith 

 of trees. All the zones have the peppery tafie. The outer 

 coat has the flavour, but little of the heat of pepper. 



III. 



Letter from the Abbe Buee on Mr. Rome' de Lisle's and 

 the AbbS Hauy's Theories of Cryfiallography , 



(Concluded from p. 39.) 



OYNTHESIS is grounded, as I mentioned, on the fad, that 

 all well formed cryftals are terminated by plain furfaces. 

 Primitive forms: Since there exift primitive forms, there mufi alfo be fecond- 

 ary forms, for the one fuppoles the exiftence of the other. 

 SecoHdary, The fecondary forms are fuch, that fedions can be made only 

 parallel to the fides of the primitive ; and when the primitive 

 has been produced by Ihefe fc(5lions, the divifion being conti- 

 nued the integrant particles are obtained. 

 Laws of the 'The mineralogical analyfis defcends from the fecondary to 



ftruftureof (he primitive form, and from the latter to the integrant par- 

 SorVthenae ^'^^^ » J"^'' ^^ ^^^ mineralogical fynthefis afcends from the inte* 

 refuiting, grant particle to the primitive, and from thence to the fecond- 



ary forms. A cryfialline edifice is therefore raifed by means of 

 the integrant particles. What are the laws of this extraordi- 

 nary architedure ? By laws I mean the difpofition of the la- 

 minae, not the means employed by nature to execute the 

 curious ftrudure. 



Laws mud exift. Hi, for the formation of the primitive, 

 and 2dly, for the conftruclion of the fecondary form. I'he 

 primitives are either fimilar to their integrant particles, or 

 they are not. If they are not, their forms niuft be parallelopi- 



pedon?> 



