(e) May 13th, 1831, Vouillé, France.
(f) May 13th, 1855, Oesel, Baltic Sea.
(g) May 13th, 1855, Bremevörde, Hanover.
(h) May 14th, 1861, near Villanova, in Catalonia, Spain.
(i) May 14th, 1864, Orgueil, France.
All the foregoing, except that of May 14th, 1861, may be found in Shepard's list, Silliman's Journal for January, 1867.
It has been shown in a former chapter that more than seven millions of shooting-stars of sufficient magnitude to be seen by the naked eye daily enter the earth's atmosphere. As the small ones are the most numerous, it is not improbable that an indefinitely greater number of meteoric particles, too minute to be visible, are being constantly, in this manner, arrested in their orbital motion. Now, it would certainly be a very unwarranted conclusion that these atmospheric increments are all of a permanently gaseous form. In view of this strong probability that meteoric dust is daily reaching the earth's surface, Baron von Reichenbach, of Vienna, conceived the idea of attempting its discovery. Ascending to the tops of some of the German mountains, he carefully collected small quantities of the soil from positions in which it had not been disturbed by man. This matter, on being analyzed, was found to contain small portions of nickel and cobalt—elements rarely found in the mineral masses scattered over the earth's surface, but very frequently met with in aerolites. In short, Reichenbach believed, and certainly not without some probability, that he had detected minute portions of meteoric matter.