34; GENERAL VIEW. 



Here, however, Bergman's investigation appears 

 to have terminated, while the Abbe Haiiy proceeded 

 to complete this theory, by determining the forms and 

 dimensions of the molecules of which he conceived the 

 primary forms were composed, and by demonstrating 

 mathematically the laws of decrement by which the 

 secondary forms might be produced. 



He also established a peculiar nomenclature, to 

 designate individually each of the observed secondary 

 forms of crystals; the nomenclature consisting of 

 terms derived from some remarkable character or 

 relation peculiar to each individual form. But the 

 disadvantage accruing to the science from encumber- 

 ing each individual crystal with a separate name, 

 must be immediately apparent, when it is considered 

 that the rhomboid of carbonate of lime alone is capa- 

 ble of producing some millions of secondary crystals 

 by the operation of a few simple laws of decrement. 



The number of names requisite to designate all 

 these, if they existed, would form an insuperable 

 obstacle to the cultivation of the science of crystal- 

 lography, even if it were practicable to devise some 

 sufficiently short and simple terms for the purpose. 



To obviate the inconvenience arising from the use 

 of so many individual names, the Gomte de Bournon 

 adopted a much simpler method of denoting the 

 secondary forms. He numbered all the individual 

 modifications he had observed, from one onwards, 

 and as the secondary forms are produced either by a 

 single modification, or by the concurrence of two or 

 more single modifications, any secondary form what- 

 ever might, according to his method, be expressed by 

 the numbers which designate all the particular modi- 

 fications which it is found to contain. 



Mr. Phillips has adopted this method in his papers 

 on oxide of tin, red oxide of copper, &c. published in 



