METEORIC STONES AND SHOOTING STARS. 729 



of a scarcity or total absence of oxygen (in its gaseous state or in the form 

 of water) in the locality whence it came. The stony portions resemble the 

 older igneous rocks, and very closely those of some active or extinct vol- 

 canoes. Phosphorus is frequentl}^ but not always associated with the iron, f 

 Iron, nickel, cobalt and phosphorus are almost constant constituents, and 

 Dr. J. Lawrence Smith states that in only three or four, out of some hun- 

 dreds, they were not recognized; and none of these minerals are associated 

 with oxygen ; and excepting copper, none of them are even found upon the 

 earth without oxygen. Phosphorus is probably always an associate of me- 

 teoric irons. 



Although analysis reveals that meteorites do contain a few minerals un- 

 known to our earth, still these minerals may be resolved into their simple 

 elements such as we are familiar with. Besides the above constituents they 

 contain oxygen, hydrogen, sulphur, phosphorus, carbon, aluminium, titani- 

 um, lead, manganese, calcium, sodium, potassium, magnesium, lithium, 

 strontium; also olivine, augite, tin, and chromium. 



Dr. J. Lawrence Smith considers that enstatite, bronzite and chrysolite 

 form 90 per cent of the earthy minerals in the aggregate mass of all me- 

 teoric stones. X 



Schreiberaite and Troillite, two minerals not found in the earth, are 

 found in meteorites. Schreibersite is a phosphuret of iron and nickel, with 

 traces of copper and cobalt. Troillite is a pr<jtosulphid of iron, with some- 

 times traces of nickel and copper. 



Some scientific persons proclaim the theory that solid meteors have been 

 ejected from the moon, others that they are formed from particles collected 

 in the atmosphere. The theory of others, is that they are small planetary 

 bodies revolving around the sun, one portion of their orbit approaching or 

 crossing that of the earth, and, being small bodies, approach too near our 

 planet and fall to the earth's surface. This presupposes their having al- 

 ways had an individual cosmical existence. 



Terzego in 1660 and Olbers in 1795 advanced the lunar theory, which 

 was supported by Laplace up to his death. Berzelius, Arago and others 

 also held the same views, but in 1836 Olbers discarded it and adopted the 

 cosmical theory. 



The average specific gravity of meteors is claimed to be about the same 

 as that of the moon, as also their chemical composition. Astronomers say 

 that a body projected from the moon with a velocity of about 8,000 feet per 

 second would go beyond the mutual point of attraction between the earth 

 and moon. Dr. Peters, who made observations at Mount JStna, estimated 

 that the velocity of some stones was 1250 feet per second, and observations 

 at Teneriffe gave 3,000 feet per second. ^ 



WIDMANSTATTIAN FIGURES. 



There are certain lines resembling scratches, developed on the smooth 



t Scientific Researcliea, J. L. Jmith, p. 287, 288. J Scientific Researches, p, 376. 



* Scieimnc liesearches by J. Lawrence Snsith. 



