500 Mr. WiJliam Croolces [June 11, 



this iron have already been collected, and specimens of the Canyon 

 Diablo meteorite are in most collectors' cabinets. 



An ardent mineralogist, the late Dr. Foote, in cutting a section 

 of this meteorite, found tlie tools were injured by something vastly 

 harder than metallic iron, and an emery-wheel used in grinding the 

 iron had been ruined. He examined the specimen chemically, and 

 soon after announced to the scientific world that the Canyon Diablo 

 meteorite contained black and transj^aient diamonds. This startling 

 discovery was afterwards verified by Professors Friedel and Moissan, 

 who found that the Canyon Diab'o meteorite contained the three 

 varieties of carbon — diamond (transparent and black), gra23hite and 

 amorphous carbon. Since this revelation, the search for diamonds 

 in meteorites has occupied the attention of chemists all over the 

 world. 



I am enabled to show you photographs of true diamonds I myself 

 have extracted from pieces of the Canyon Diablo meteorite (Figs. 29, 

 30), five pounds of which I have dissolved in acids for this purpose 

 — an act of vandalism in the cause of science for which I hope 

 mineralogists will forgive me. A very fine slab of the meteorite, 

 weighing about seven pounds, which bus escaped the solvent, is on 

 the table before you. 



Here, then, we have absolute proof of the truth of the meteoric 

 theory. Under atmospheric influences the iron would rapidly oxidise 

 and rust away, colouring the adjacent soil with red oxide of iron. 

 The meteoric diamonds would be unaffected, and would be left on 

 the surface of the soil to be found by exj^lorers when oxidation had 

 removed the last proof of their celestial origin. That there arc still 

 lumps of iron left at Arizona is merely due to the extreme dryness of 

 the climate and the comparatively short time that the iron has been 

 on our i)lanet. We are here witnesses to the course of an event which 

 may have happened in geologic times auy where on the earth's 

 surface. 



Although in Arizona diamonds have fallen from above, confounding 

 all our usual notions, this descent of precious stones seeius what is 

 called a freak of Nature lather than a normal occurrence. To the 

 modern student of science there is no great difference between the 

 composition of our earth and that of extra-terrestrial masse«. The 

 mineral peridot is a constant extra-terrestrial visitor, present in most 

 meteorites. And yet no one doubts that peridot is also a true con- 

 stituent of rocks formed on this earth. The spectroscope i ^eals thafc 

 the elementary composition of the stars and the earth are ^ '^^ much 

 the same ; so does the examination of meteorites. Inde». only 



are the selfsame elements present in meteorites but they arj combined 

 in the same way to form the same minerals as in the rust of the 

 earth. 



This identity between terrestrial and extra-terrestrial rocks 

 recalls the masses of nickeliferous iron of Ovifak. Accompani( d with 

 graphite they form part of the colossal eruptions which have covered 



