Page:Popular Science Monthly Volume 18.djvu/559

3h.	45	m.	to	3h.	50	m.,	1	meteor.		4h.	45	m.	to	4h.	50	m.,	3	meteors.
3	50		"	3	55		1	"		4	50		"	4	55		6	"
3	55		"	4	0		0	"		4	55		"	5	0		6	"
4	0		"	4	5		0	"		5	0		"	5	5		7	"
4	5		"	4	10		0	"		5	5		"	5	10		1	"
4	10		"	4	15		0	"		5	10		"	5	15		2	"
4	15		"	4	20		0	"		5	15		"	5	20		7	"
4	20		"	4	25		5	"		5	20		"	5	25		7	"
4	25		"	4	30		0	"		5	25		"	5	30		12	"
4	30		"	4	35		4	"		5	30		"	5	35		11	"
4	35		"	4	40		0	"		5	35		"	5	40		5	"
4	40		"	4	45		4	"		5	40		"	5	45		9	"

Table showing the same Meteors as above by the Quarter-Hour, Half-Hour, and Hour.

3h.	45	m.	to	4h.	0	m.,	2	$\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$	2	$\scriptstyle {\left.{\begin{matrix}\ \\\\\ \ \end{matrix}}\right\}\,}$	15	Moon during first hour.	4h.	45	m.	to	5h.	0	m.,	15	$\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$	25	$\scriptstyle {\left.{\begin{matrix}\ \\\\\ \ \end{matrix}}\right\}\,}$	76	Moon during second hour.
4	0		"	4	15		0						5	45		"	5	15		10
4	0		"	4	30		5	$\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$	13				5	15		"	5	30		26	$\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$	51
4	30		"	4	45		8						5	30		"	5	45		25

Remarks.—1. The maximum was at 5^h 30^m, when five Leonids were seen in one minute.

2. The shortest path—two degrees—was that of a meteor nearly stationary, seen in Leo at 5^h 18^m. The longest forty degrees crossed Ursa Major at 5^h 20^m.

3. The average length of path during the first hour was six degrees; in the second, about seven; the increase being probably due to the absence of moonlight.

4. At least three distinct meteoric swarms move in the track of Tempel's comet (1866 I). One has just passed or is passing perihelion; the second will pass about 1887-'88; and the maximum group about the close of the century.

5. The meteors on the morning of the 14th inst. were more numerous than those of the August shower; a fact quite remarkable when it is remembered that it is fourteen years since the great display of the principal cluster.

6. The estimated periods of the comet and the meteor groups of the Leonid ring are as follows:

Tempel's comet	33·176	years.
Group A	33·250	"
Group B	33·333	"
Group C	33·500	"

The last is derived from the showers of 1813, 1846, 1847, 1879, and 1880.

7. Oppolzer's period of Tempel's comet, as given above, is perhaps too short. If this body was a return of the comet of 1866, its mean period is 33·283 years—very nearly the same as the meteoric periods.