NOTES TO BOOK XV. 281 



M. Fuchs afterwards (in Schweiggers Journal) retracted 

 the opinions he had put forwards on this subject. 



(p.) p. 277. For additions to our knowledge of the 

 Dimorphism of Bodies, see Professor Johnstone's valuable 

 Report on that subject in the Reports of the British Asso- 

 ciation for 1837. Substances have also been found which 

 are trimorphous. We owe to Professor Mitscherlich the 

 discovery of dimorphism, as well as of isomorphism : and 

 to him also we owe the greater part of the knowledge to 

 which these discoveries have led. 



I do not know that I have anything to add to the 

 history of the Progress either of Crystallography or of 

 Classificatory Mineralogy ; but I may notice some of the 

 works which have recently appeared, looking at them in 

 the point of view to which the text conducts me. 



Elemente der Krystallographie, nebst einer tehellarischen 

 Uebersicht der Mineralien nach der Krystallformen, von 

 Gustav Rose. 2. Auflage. Berlin, 1838. The crystal- 

 lographic method here adopted is, for the most part, that 

 of Weiss. The method of this work has been followed in 



A System of Crystallography, with its Applications to 

 Mineralogy. By John Joseph Griffin. Glasgow, 1841. Mr. 

 Griffin has, however, modified the notation of Rose. He 

 has constructed a series of models of crystalline forms. 



Frankenheim's System der Krystalle. 1842. This work 

 adopts nearly the Mohsian systems of crystallization. It 

 contains Tables of the chemical constitution, inclinations 

 of the axes, and magnitude of the axes of all the crystals 

 of which a description was to be found, including those 

 formed in the laboratory, as well as those usually called 

 minerals; 713 in all. 



Fr. Aug. Quenstedt. Methode der Krystallographie, 

 1840, employs a fanciful method of representing a crystal 



