240 METALS IN THE ATMOSPHERE. 



station des Avaiits below the Moutiers; at (S.IOO tVot at tlie hospice of 

 the Great St. Bernard — and compared the evaporation residue from 

 this snow with the dust collected in the towers of several cathedrals 

 at Paris, Geneva, Lausanne, Varsovie. and at Samara on the Volga. 

 He concluded that iron is as surely present in recent snows as in the 

 dust of centuries accumulated in the clock towers of the old churches. 

 In all cases the appearance of this metal indicated that it had been 

 subjected to high temperatures. 



These corj^uscles, found always in greater (piantities in the snows of 

 lower altitudes than from higher regions, do not always have the same 

 characteristics, and students of them have classified them into several 

 groups : 



1. Irregular amorphous grayish fragments, measuring from 0.1 to 

 0.2 nnn. in diameter. 



2. Mannnilated particles, black and o[)a<iue, much smaller, measur- 

 ing only 0.01 to 0.05 mm. 



3. Fibrous particles of about the same size. 



4. Spherical corpuscles, black and opaque, diameter O.Oi to 0.02 

 mm. 



5. Corpuscles apparently with a tiny vase-like neck. 



Moreover, these minute ferruginous corpuscles divide into two 

 classes, some which have been deposited on the surface of the earth, 

 others of an extra-terrestrial origin. The effects of showers of 

 meteors are shown in an incontestable manner. Ehrenberg, Arago, 

 Quetelet, Daubree, and Nordenskiold have brought forward a great 

 number of facts in this connection. Examining a fine dust which on 

 the 25th of January, 1859, fell in the Indian Ocean, covering the 

 decks of the good ship JosiaJt Bates, Ehrenberg showed that this 

 powder, which to the naked eye appeared to be only little agglom- 

 erate grains, was in reality formed l)v drops comjiosed of metallic 

 iron and iron oxide solidified and creased in a manner analogous to 

 that of the Batavian tears. He considered this ])r()()f that a mass of 

 meteoric iron is nuide incandescent by the friction of the air. Sedi- 

 ments of this sort may come from the superlicial fusion of meteorites, 

 or, as Daubree has indicated in his memoir on the meteorite of 

 Orgueil," th"y may be simply the result of disintegration. 



The dust is so friable that some bits were reduced to a powder by 

 the pressure of the fingei's. Its difl'erent i)arts are cemented together 

 with some alkaline salts so soluble in water that this liquid will 

 Avork a (;()mplete disintegration into a line j)()Wiler that will pass 

 through the hardest filtei's. Numerous cases of rains of lire which 

 should apparently be attributed to the fall of incandescent debris of 

 meteorites are familiar. The Baron de Reichenbach insisted strongly 



o Journal des Savants, 1870. 



