116 THE METEORITES.— THEIR ORICm AND CHARACTER. 



might the physicist explain the dispersion of boulders in the northern drift,* 

 or the origin of the large nuggets in the gold placers by supposing that they 

 were meteorites, as to explain the earth's structure by the meteoric theory. 



The further supposition that the earth has been formed from meteoric 

 matter that became entirely fused from the impact of the falling masses is 

 one that makes an assumption and then deprives us of every means of dis- 

 proving or proving it. 



Everything relating to the state of the earth prior to its fluid condition 

 is of course a matter of conjecture, and theories relating to it are beyond 

 scientific discussion, as belonging to the unknown and unknowable. 



The origin of meteorites, as shown by their structure, yields but little 

 assistance to the theory of the introduction of life upon this planet through 

 their agency; since the conditions under which they were formed, and those, 

 so far as can be ascertained, to which they have been since subjected are not 

 compatible with life as understood upon this globe.f 



In other words it may be said that meteorites show in their structure 

 that they have been formed from molten liquid material, while their chemical 

 composition is such as to show that they could not have been exposed to air 

 and water upon any globe in conditions compatible with life as we under- 

 stand it. If their structure points to an igneous origin, and their composition 

 shows that they could not have been exposed to conditions such as earth-life 

 demands, then Sir William Thomson was not right in claiming that it was 

 scientific to suppose that life was brought to this earth by meteorites. It 

 certainly only pushes the question of life a little farther off; it begs the 

 question but does not solve it, even could it have been shown that life might 

 have been thus brought here. Ztillner was indeed right in opposing tliis 

 theory and regarding it as iinscientific. Assuredly, the germs inclosed in 

 crevices would be destroyed by the cold of space, as much as the exterior 

 ones would be by tlie heat generated by the passage of the meteorite 

 throu"'h the air. It is not intended to state that water or air could not be 

 present on the body from which meteorites come, but that the meteorites 

 could not have been exjDosed any length of time to such agencies, or their 

 constitution would liave been changed. 



* Siuce the above fl'as written such au cxphmation has been publislictl, entitled : "Raguavok — tlic Age 

 of Fire and Gravel," — by Ignatius Donnelly. 



t W. Thomson, Proc. British Assoc., 1871, pp. civ., cv. ; 1877 (Sect,), p. 43 ; A. Thomson, ibid., 1877, 

 p. 75 ; Helmholtz, Popular Scientific Lectures (Sec. Ser.), 1881, pp. 193, 196, 197; Nature, 1S75, xi. 212; 

 J. C. P. Zollner, "Ueber die Natur der Cometen, Leipzig," 1S72, p. 21; Walter Flight, Pop. Sci. Rev., 

 1877, xvi. 390-401; David Forbes, Geol. Mag., 1872 (1), ix. 23i, 235. 



