METEORIC STONES. 



503 



At the November meeting of the British 

 Geological Society, a letter was read from the 

 British embassy at Copenhagen, saying that 

 a Swedish scientific expedition, just returned 

 from the coast of Greenland, had brought home 

 a number of masses of meteoric iron found 

 there on the surface of the ground. The largest 

 was said to weigh 25 tons. Mr. David Forbes, 

 who had recently returned from Stockholm, 

 being present at the session, said that he had 

 had an opportunity of examining these remark- 

 able masses of iron, discovered in 1870, by one 

 Swedish expedition, which had brought home 

 several blocks of considerable size, to which 

 collection about twenty more fine specimens 

 had been added by a second Swedish expedi- 

 tion in 1871 : 



The largest, weighing more than 49,000 Swedish 

 pounds, or about 21 tons English, with a maximum 

 sectional area of about 42 square feet, is now placed 

 in the hall of the Eoyal Academy of Stockholm ; 

 while, as a compliment to Denmark, on whoso terri- 

 tory they were found, the second largest, weighing 

 20,000 Ibs., or about 9 tons, has been presented to 

 the Museum of Copenhagen. Several of these speci- 

 mens have been submitted to chemical analysis, 

 which proved them to contain nearly 5 per cent, of 

 nickel, with from 1 to 2 per cent, of carbon, and to 

 be quite identical in chemical composition with many 

 aerolites of known meteoric origin. When polished 

 and etched by acids, the surface of these masses of 

 metallic iron shows the peculiar figures or markings 

 usually considered characteristic of native iron of 

 meteoric origin. The masses themselves were dis- 

 covered lying loose on the shore, but immediately 

 resting upon basaltic rocks (probably of Miocene 

 age), in which they appear to have originally been 

 imbedded ; and not only have fragments of similar 

 iron been met with in the basalt, but the basalt itself, 

 upon being examined, is found to contain minute 

 particles of metallic iron, identical in chemical com- 

 position with that of the large masses themselves, 

 while some of the masses of native iron are observed 

 to enclose fragments of the basalt. As the chemical 

 composition arid mineralogical character of these 

 masses of native iron are quite different from those 

 of any iron of terrestrial origin, and altogether iden- 

 tical with those of undoubted meteoric iron, Prof. 

 Nordenskjold regards them as aerolites, and accounts 

 for their occurrence in the basalt by supposing that 

 they proceeded from a shower of meteorites which 

 had fallen down and buried themselves in the molten 

 basalt during an eruption in the Miocene period. 

 Notwithstanding that these masses of metallic iron 

 were found lying on the shore between the ebb and 

 flow of tide, it has been found, upon their removal 

 to Stockholm, that they perish with extraordinary 

 rapidity, breaking up rapidly and falling to a fine 

 powder. Attempts to preserve them, by covering 

 them with a coating of varnish, have as yet proved 

 unsuccessful ; and it is actually proposed to preserve 

 them from destruction by keeping them in a tank of 

 alcohol. 



Mr. Russell, Government Astronomer at 

 Sydney, Australia, in April last, received the 

 greater portion of a meteoric stone which fell 

 at Barrata some years ago. It originally 

 weighed about 300 Ibs. In a communication 

 to the American Journal of Science, Prof. J. 

 L. Smith remarks upon the occurrence of five 

 enormous meteorites in the Mexican desert, 

 in the western part of the province of Coha- 

 huila. The largest of these masses weighed 



from 1 to 2 tons each. The distance from any 

 one meteorite to its nearest neighbor is from 

 85 to 165 miles. They are closely allied in 

 composition, and in physical properties, such 

 as softness of iron, and freedom from rusty 

 crusts over the exterior, and Prof. Smith makes 

 the plausible suggestion that at some epoch, 

 probably far remote, they were the products 

 of the fall of one meteoric mass, moving from 

 the northeast to the southwest. A sixth me- 

 teorite, found in the same vicinity, has peculiar 

 chemical and physical properties, separating it 

 entirely from the others, and is therefore sup- 

 posed to have fallen at a different time. 



A writer in Nature reasons, from various 

 considerations, that the maximum velocity of 

 meteoric stones reaching the surface of the 

 earth is only between 159 and 197 feet a sec- 

 ond. This velocity does not exceed one-tenth 

 of the initial velocity of a rifle-bullet. And, 

 as the penetrating power of a given projectile 

 is proportional to the square of its velocity, 

 its power of penetrating the earth would only 

 be one-hundredth part as great as that of a 

 projectile of similar mass and dimensions 

 moving at the rate of a rifle-bullet. It is 

 well known that the maximum velocity of a 

 falling body is attained when the required 

 velocity is such that the resistance is at each 

 instant equal to the weight of the moving body. 

 In the case of small masses moving in the air, 

 it may be shown that this velocity is quite 

 moderate. 



In his address before the British Association, 

 the president, Sir William Thomson, indulges 

 in the subjoined novel speculations regarding 

 the part which he thinks meteorites may pos- 

 sibly have played, in endowing this earth with 

 the germs of vegetable life : 



"When a lava-stream flows down the sides of Vesu- 

 vius or Etna, it quickly cools and becomes solid ; 

 and after a few weeks, or years, it teems with vege- 

 table and animal life, which originated by the trans- 

 port of seed and ova, and by the migration of indi- 

 vidual living creatures. When a volcanic island 

 springs up from the sea, and after a few years is found 

 clothed with vegetation, we do not hesitate to assume 

 that seed has been wafted to it through the^air, or 

 floated to it on rafts. Is it not possible, and, if pos- 

 sible, is it not probable, that the beginning of vege- 

 table life on the earth is to be similarly explained ' 

 Every year thousands, probably millions, of frag- 

 ments of solid matter fall upon the earth whence 

 came these fragments ? What is the previous history 

 of any one of them ? Was it created in the beginning 

 of time an amorphous mass ? This idea is so unac- 

 ceptable that, tacitly or explicitly, all men discard it. 

 It is often assumed that all, and it is certain that 

 some, meteoric stones are fragments which had been 

 broken off from greater masses, and launched free 

 into space. It is as sure that collisions must occur 

 between great masses moving through space, as it is 

 that ships, steered without intelligence directed to 

 prevent collision, could not cross and recross the 

 Atlantic for thousands of years with immunity from 

 collisions. When two great masses come into col- 

 lision in space, it is certain that a large part of each 

 is melted; but it seems also quite certain that in 

 many cases a large quantity of debris must be shot 

 forth in all directions, much of which may have ex- 

 perienced no greater violence than individual pieces 



