302 MINERALOGY. 



also been busy analyzing Canadian minerals. Yery interesting are 

 the analyses of scapolites by Mr. Adams. He found them all to con- 

 tain chlorine, the overlooking of which was probably the cause of the 

 evident errors of previous analyses. 



The relationship in which hornblende and pyroxene stand to each 

 other has always been a favorite subject. Although each species has 

 numerous varieties of very variable composition, each possesses the 

 same chemical varieties, and they are therefore considered as dimorphous. 

 Moreover there is a very definite relationship between their forms, since 

 doubling the length of one axis in pyroxene gives the axes of hornblende. 

 Another feature that has attracted much interest is that pyroxene tends 

 to alter its own internal molecular structure into that of hornblende. 

 This results in giving us quite perfect crystals apparently pyroxene, 

 but which possess the cleavage and optical iiroperties of the allied spe- 

 cies. Since the two species may be identical in composition, this has 

 usually been spoken of as a case of paramorphism, of which we have 

 some other illustrations. Calcium carbonate crystallized as aragonite 

 can, for example, be internally altered tocalcite, which change involves 

 no chemical alteration. But Mr. Harrington among the apatite deposits 

 has succeeded in finding pyroxene crystals in which this process of alter- 

 ation was in progress, and in some cases had progressed to that extent 

 that the crystals were internally pyroxene and externally of horn- 

 blende. Analyses of the materials in all cases showed that a chemical 

 change had taken place, which was largely expressed in a loss of lime. 

 In other words, the pyroxene was changed, not into a hornblende of a 

 like comj)osition, but a hornblende of different composition. Pyroxene 

 crystals altered into hornblende have been called uralite, because first 

 brought from the Urals by Gustav Eose. Professor Harrington's analy- 

 ses demonstrate that his crystals are to be considered as pseudomorphs, 

 and not as paramorphs. 



Mr. Hidden has been seeking minerals in the Southern States. 

 Among others he has found some very beautiful, transparent, green 

 crystals of spodumene, which are a novelty and an interesting addition 

 to the varieties of this species. Some immense crystals of sphene, 

 weighing fifty pounds or more, have been brought from Eenfrew, in 

 Canada. Dr. Shepard has bought the celebrated Graves Mountain, 

 Georgia, and has mined from it great numbers of very large and very 

 beautiful rutile crystals ; and the shelves of the mineral dealers will be 

 found enriched with a great deal of material from new localities that 

 have been develoiDcd during the past two years. 



Meteorites. — When one remembers how very few are the meteorites 

 that have been seen to fall and have then been found, and the general 

 and keen interest felt by the whole scientific world in these celestial 

 bodies, the very remarkable fall of meteorites that took place in our 

 country last year must be considered as an important event. Most of the 



