184 Fretp Museum oF NATURAL History — GEo.toey, Vor. III. 
from noon to 6 P. M. 124, and from 6 P. M. to midnight 60. Hence it 
seems probable that some of the diminution in the number of falls 
is due to lack of observers, although Newton* seemed to conclude 
from studies of the orbits of the morning falls that lack of observ- 
ers had little to do with their scarcity. Lack of meteorites during 
morning hours may also be due in part, as Newton suggested, to the 
fact that such as have retrograde motion are more likely to be burned 
up by the greater velocity with which they strike the earth’s atmos- 
phere. This increase in velocity 1s not so great as might be supposed 
since Lowell has shown f that it cannot exceed 2.66 miles per second. 
Yet Pickering t thinks it is sufficient to destroy all that have retro- 
grade motion, or that the velocity of such as have retrograde motion 
would be higher than any that has yet been recognized. It is not 
clear how such an increase would be very apparent if this increase at 
most is only 2.66 miles per second. On account of the above proba- 
bilities Pickering is of the opinion that most if not all of the meteorites 
which fall in the morning hours are moving at so slow a speed that 
they are overtaken by the earth. Schiaparelli, who gave the matter 
much study and to whom we are indebted for extensive researches 
in the relations between comets and meteors, concluded that many 
meteorites had hyperbolic velocities and hence must come from the 
world of fixed stars rather than from comets or the solar system. | 
Newton assigned to the stone of Stannern a velocity of 45 miles per 
second, and concluded that most meteorites are allied to short period 
comets in their velocities.§ Pickering 4 regards it doubtful whether 
any stony meteorites move fast enough to be accredited with cometary 
velocities. 
The hourly falls of the writer’s table are shown plotted in Plate LIX. 
It will be observed that the peak of the falls occurs at 3 P.M. Picker- 
ing has shown ** that other things being equal the greatest number of 
meteorites would be expected when the Earth’s quit is highest above 
the horizon and that this occurs for the northern hemisphere, longi- 
tude 90°, at 3 Pp. M., May 6. This high point agrees with that of the 
greatest number of meteorites, for they are most numerous in May 
* Am. Jour. Sci., 1888, 3,36, ao. 
{ ocience, IN5S., 1000,40, 3302 
t Popular Astronomy, 1910, 18, 264. 
|| Entwurf einer Astronomischen Theorie der Sternschnuppen. Boguslaw- 
ski’s translation, 1871, p. 228. 
S$Am: Jour, Sct, 188853530, 11, anders 
J Popular Astronomy, rg1o0, 18, 276. 
Ft OD. Ci Dos. 
