204. 



any trustworthy result. He is, however, inclined to believe, 

 that both metals reflect most at a perpendicular incidence. 



From the foregoing detail of the properties, in several 

 respects so different, of this substance in its normal and ano- 

 malous states, the author thinks he is warranted in pro- 

 nouncing it the first observed instance of an approach to 

 dimorphism in a metaUic alloy ; and one, the mode of pro- 

 duction and characteristics of which present several points 

 of interest. 



The conditions under which the alloy was aggregated, 

 involved extremely minute division of the metal, great pres- 

 sure in forcing the divided particles into contact, and nearly 

 the exclusion of air. Considerable electrical disturbance 

 may have also co-operated; such, together with induced mag- 

 netism, being the constant accompaniments of motion in 

 heavy machinery. By re-establishing these conditions, under 

 suitable arrangements, the author hopes to repeat the re- 

 sults thus accidentally first obtained, and so produce possibly 

 dimorphous states of other metals or their definite combina- 

 tions. 



There is but one body which occurred to the author, 

 presenting an analogy to this anomalous alloy, namely, indigo ; 

 whose fracture, it is well known, is fine earthy, and of the 

 usual blue colour, but becomes coppery, or assumes the me- 

 tallic lustre on beins: rubbed or burnished. 



DONATIONS. 



Uber den Gahanismus gegen ortliche Krankheiien, von 

 Dr. Gustav Crusell. 



RecueUdes Actsde la Seance PiibUque de VJcademie Im- 

 periale des Sciences de St.Petersbotirg, tetnie le 29 Decemhre, 

 1840. 



^Icmoires de V Academie Impertale des Sciences de St, 

 Petersboiirg. 6™* Serie. Sciences Politiques, ^-c. Tome IV. 

 Livraison 6, and Tome V. Livraisons 1-4. 



