280 NOTES. 



must be placed those relating to the fall of meteoric stones. The 

 fact itself, so long doubted, has now been established by an accumu- 

 lation of the most positive and unexceptionable evidence. The stones 

 have been seen to fall, and taken up in a still heated state ; there 

 can be no manner of doubt about the fact, although the explanation 

 is extremely difficult. All these stones are found on examination to 

 resemble each other in their general characters ; they usually consist 

 of an earthy material, having disseminated through its substance 

 globules and small masses of metallic iron containing nickel in the 

 state of alloy. The stones are often covered by a thin vitreous crust, 

 as if partial fusion had commenced. It is well known, also, that 

 large masses of soft, malleable iron, also containing nickel, are found 

 in several places far removed from each other, lying loose upon the 

 earth, as in South America and in Siberia, and no doubt can exist of 

 the meteoric origin of these masses. It has been conjectured that 

 these meteoric stones proceed from the moon, having been shot out 

 from volcanoes with such violence as to be brought within the reach 

 of the earth's attraction. A view now more generally received sup- 

 poses the existence in space of very numerous small bodies, moving 

 in more or less regular orbits around the sun and larger planets, which 

 at certain periods undergo such perturbation that their motion be- 

 comes completely deranged, and they at length fall upon the surface 

 of the earth or other planet, whose attraction has been the exciting 

 cause of the derangement of their orbits. Whatever may be their 

 real origin, they are by common consent looked upon as foreign to 

 the earth : their physical constitution is completely different from 

 any known minerals. But what is exceedingly remarkable, and par- 

 ticularly worthy of notice as strengthening the argument that all the 

 members of the solar system, and perhaps of other systems, have a 

 similar constitution, no new elements are found in these bodies ; they 

 contain the ordinary materials of the earth, but associated in a man- 

 ner altogether new, and unlike anything known in terrestrial miner- 

 alogy. Note by a Correspondent. 



(9.) The researches on this subject were conducted chiefly by the 

 late Baron Fourier, perpetual secretary to the Academy of Sciences 

 of Paris. See his Theorie Analytique de la Chaleur, 1822. 



(10.) See Geological Researches by Sir Henry de la Beche, 1834. 



(11.) That the rocks anterior to the protozoic may represent a 

 time of earlier life is admitted by Sir E. Murchison, who, speaking 

 of the Lower Silurian rocks which he examined in Sweden, says, 

 " We have come to the conclusion that the lowest of these beds that 

 are fossiliferous are the exact equivalents of the Lower Silurian strata 

 of the British Isles, and that they have been formed out of, and rest 

 upon slaty and other rocks, which had undergone crystallization 

 before their particles were ground up to compose the earliest beds in 

 which the remains of organic life appear. We apply to these crys- 



