564 Reviews — Prof. Judd — On Volcanoes. 



amongst them not less than 999 out of 1,000 parts of the earth's 

 crust, and all of these twelve common terrestrial elements occur in 

 meteorites, we see how closely these small bodies unite us to the 

 other heavenly bodies around. 



One fact, however, the author points out, of great importance, 

 namely, that the way in which these elements occur in meteorites 

 differs materially from their mode of occurrence on our earth's crust, 

 as if the circumstances surrounding their union were very unlike those 

 of our earth's surface. We have, for instance, Meteorites (called 

 Holosiderites) which are masses almost wholly composed of metallic 

 iron or of iron alloyed with nickel — others (Syssiderites) formed of 

 a network of iron inclosing stony materials — others (Sporadosiderites) 

 of stony material with particles of metallic iron disseminated through 

 it — and lastly Asiderites, which contain no metallic iron, but consist 

 entirely of stony materials. 



The stony materials of these (^Asiderites) have been matched by 

 certain ultra-basic rocks which have clearly been carried up with 

 the other lavas from great depths in the earth's crust. Nodules 

 composed of the same minerals which are so highly characteristic 

 of meteorites occur in basaltic lavas and tuffs and also in the centres 

 of volcanic bombs which are thrown out of craters during eruptions. 



Lastly, and still more interesting, is the discovery that materials 

 similar to the metallic portion of meteorites, and consisting of 

 nickeliferous iron, also occur in deep-seated portions of the earth's 

 crust, and have been brought to the surface during periods of igneous 

 activity. 



Large blocks of iron like ordinary metallic meteorites (being 

 composed of iron alloyed with nickel and cobalt) were found in 

 1870 by Prof. Nordenskiold at Ovifak, Disko Island, off the coast 

 of Greenland (see Geol. Mag. 1872, Vol. IX. p. 462, etc.). These 

 were at once concluded to be a number of meteorites which at some 

 past time had fallen upon the earth's surface. 



But a further examination of the locality showed that the rocks 

 composing the basaltic dykes adjacent to the iron-masses were fidl 

 of particles of metallic iron! 



Thus another link is added to the wondrous chain by which our 

 earth is united to other and distant worlds ; planet to planet, and 

 star to star ; binding the whole material universe together by the 

 law of Continuity. 



Turning from our earth to the sun, we see in its brilliant promi- 

 nences evidence of a volcanic energy far surpassing in grandeur 

 anything of which we can form an idea, yet there can be no doubt 

 that its surface is but a highly accelerated and immensely magnified 

 repetition of what goes on in the pigmy volcanos on our earth. 



Our own satellite presents us with the obverse of the sun's busy 

 energy. In the moon we see the condition to which a planet may 

 be reduced in which all cosmical energy has died out, because the 

 motive power of that energy (its atmosphere and ocean) no longer 

 exists. It is, as our American cousins would say, "played out." 



