26 BULLETIN 94, UNITED STATES NATIONAL MUSEUM. 



primeval forest; yet the mass was not deeply buried, a small project- 

 ing portion leading to its discovery. 



The Bacubirito iron, weighing at a rough estimate 20 tons, lay 

 in a soft soil, with its surface but little below the general surface of 

 the field around it. 



It is a noteworthy fact that the members of different meteor showers exhibit 

 visible features which in certain cases are quite dissimilar. This arises from 

 the circumstance that the various showers encounter the earth at different 

 angles, and their apparent speed depends in a great measure upon this. Thus 

 the meteors of November 13 (Leonuls) are moving in a direction opposite to the 

 earth ; hence their velocity is very great, being about 44 miles per second. But 

 the meteors of November 27 (Andromedes) are moving in nearly the same direc- 

 tion as the earth, and hence have to overtake us, so that they apparently move 

 very slowly, their speed being only 11 miles per second. The Leonids above 

 referred to, together with the Perseids of August 10 and the Orionids of Octo- 

 ber 18-20, are good examples of the swift-moving meteors, and they are almost 

 invariably accompanied by phosphorescent streaks. The slow meteors, of which 

 the Andromedes are a type, throw off trains of yellowish sparks.' 



In conclusion, the result of the investigation may be said to have created a 

 strong presumption in favor of the following general deductions : 



(a) That the velocities of meteorites are materially changed by the resist- 

 ance of the atmosphere, and, in general, by a fractional part of the velocity 

 which is independent of the velocity of approach. 



(&) That the superior limit for incandescence is probably about 150 miles 

 above the earth's surface. 



(c) That no iron meteor the original weight of which was less than 10 to 20 

 pounds reaches the earth's surface, and that when a meteor does so the tem- 

 perature of its center is not in general above that of liquid air (assuming the 

 temperature of space to be zero).* 



All statements relative to the temperature of meteorites imme- 

 diately after reaching the ground must be accepted guardedly owing 

 to their extremely contradictory character. According to Haidinger, 

 some stones which fell in Styria in 1859 continued in a state of incan- 

 descence for from five to eight seconds, and for a quarter of an hour 

 were too hot to be handled without burning. Beinert, in his account 

 of the Braunau iron, states that for six hours it also remained too 

 hot to be handled. On the other hand, the Dhurmsala stone is stated 

 to have been intensely cold when picked up immediately after falling. 



The reports of the setting of fires by the falling of meteorites must 

 also be taken with the same degree of allowance. In the cases of both 

 the Allegan and Winnebago falls the stones struck on the dried grass, 

 which, though pressed closely against the surfaces, was not charred 

 in the least. Indeed, one of the Winnebago stones fell on a stack of 

 dry straw, but without igniting it. 



1 Handbook of Descriptive and Practical Astronomy, by George F. Chambers, Sun, 

 Planets. Comets, ed. 4, vol 1, p. 635. 



2H. E. Wimperis, Nature (London, Eng.), vol. 71, 1904, p. 82. 



