DECEMBER 24, 1896] 
NATURE 
175 
ingly this latter point, still very near to « Zeonzs in the middle 
of the sickle, was a very well defined and exactly marked centre 
of the shower’s radiation, since nineteen out of thirty, or 63 
per cent. of all the tracks of possible Leonids recorded, pro- 
ceeded from within 3° or 34 from it, outwards towards all 
directions. 
The chief apparent wandering from this centre shown by the 
eleven erratic-flighted Leonids was south-westwards, towards 
a, k Cazcr?, where seven of those outlying tracks (including the 
three wide-circle-grazing path-lines) are loosely collected ; but 
of these seven, some may have belonged, as was surmised above, 
to contemporaneous sparse showers at about 135°, + 17°, and 
150°, — 12°; andasthe four paths which strayed north-eastwards 
from the sickle, though forming a fan-like group roughly focused 
at about 155°, + 35, near f/, ¢ Leones Menorzs, were no doubt | 
Leonid stragglers, shooting in proper numbers for their own half 
of a field supposed to be about evenly strewn with them, from no 
really existing radiant centre there, there would thus seem to 
have been among the strayed Leonids themselves no tendency 
that could be noticed to move in side-flows and tangent-streams 
presenting laterally drawn-out and branching radiations strong 
or distinct enough to be discernible. No such lateral disper- | 
sions or divisions, therefore, seemed, from all the tracks’ pro- | 
jections, to have affected the shower’s radiation with any per- | 
ceptible apparent changes from the very exactly defined centre, | 
with even, and not very great dispersion round it, which has | 
been usually observed asa strikingly conspicuous feature of this 
star shower’s radiation at its principal returns. 
Positions of this after-shower’s radiant-point, obtained formerly 
and in the present year, are not in very perfect, although in fair | 
general accordance; as even inits bright 
display of November 14 a.m., 1868,! 
the flight was seen breadthwise, though more distant there than 
from Bristol, it subtended an arc in the sky of fully 12°. The 
computed speed of flight, 48 miles per second, although cer- 
tainly terrific, does not exceed the known meteor speed of the 
Leonids, 43 miles per second, very greatly. One of the sporadic 
meteor-paths observed by Mr. Denning was directed from the 
| vicinity of A Hydre, and the other four apparently from Gemznz 
or Zaurus, and from Ursa Major. 
A fairly satisfactory comparison of this year’s observations of 
the Leonids with the views obtained of them last year, although 
much frustrated by the cloudy weather which prevailed in 
England on those nights, in both years, when the earth’s passage 
through the densest part of the meteor-system was expected, may 
be made rather scantily, but perhaps not insufficiently to show 
the increased intensity of the display this year in its gradual 
progress onwards towards its maximum The subjoined figure 
was prepared to assist the recognition of the separate streams 
| of which returning signs have no doubt been visible in some 
of the present year’s and of the last two years’ watches. The 
relations of the leading and following side-showers, a and 
6 in the figures, to the central one A, in duration and separation- 
distance, are supposed to be as shown by Mr. Marsh’s similar 
projection in a figure! of the chief showers in 1865-68 ; for the 
leading showers, 12 hours, ending 64 hours before, and for the 
following shower, 133 hours, beginning 6 hours after the limits 
of the middle-shower’s duration, whose entire range, in time, on 
the ecliptic also only reached 44 hours for the two tracts together 
in which the earth there met with and passed through the middle 
stream in 1866-7. 
The central stream’s node on the ecliptic is also supposed tu 
places were assigned to it, at Rome, ‘‘at 
the centre of the five stars of Leo’s 
sickle” (1493°, + 224°) at Moncalieri, 
Piedmont, ‘*exactly between vy and 
5, ¢ Leonzs” (153°, + 22°), and at Madrid, 
“close to » Leonzs” (150°, + 17° 
mean of these places, 151°, + 204°). 
In Nature, November 30, 1871, a 
description of the shower’s appearance 
in England on the morning of No- 
vember 15, 1871, assigns the radiant- 
point’s position from twenty-six Leonid 
paths as ‘‘not very well defined, but 
approximately close to ¢ Leonzs” (152°, 
+ 24°). On the morning of November 
I5 in the present year, Mr. Corder 
obtained a position of 150°, + 24°, from forty-three Leonids ; 
and four of the seven paths mapped at Walthamstow at day- 
break on that morning by Mr. Besley (see note on p,. 174) 
diverged accurately from 149°, + 22°—all slightly onward in 
R.A. from the principal radiant-point in Leo at 148°, + 23° ; 
but the positions are too slenderly consistent to make this small 
difference appear to be of very much importance. 
In a watch for the Leonids, from 4 to 6 a.m. on the 15th 
ult. at Bristol, Mr. Denning mapped the apparent paths of ten 
Leonids and five sporadic meteors. Three of the Leonids (one 
of them a foreshortened flash as bright as Jupiter) diverged 
accurately from 150°, + 23°, the other seven (also including one 
as bright as Jupiter) being directed eastwards from the lower 
part of Zeo’s sickle-circle. Of the three true-pathed Leonids, 
a small, very foreshortened one, of 3rd mag., leaving a streak, 
which fell at 5.45 a.m., about 2° from 7 down the sickle- 
handle, was also seen and mapped at Slough, at 5.444, of 2nd 
mag,. leaving a streak for two seconds, but shooting through 
12° in half a second to near a Orzonzs from the stars in the head 
of Monoceros, this path among the stars being from 50° to 60° re- 
moved by parallax (owing to the long base line of 84 miles, 
nearly due east and west, between Slough and Bristol) from the 
short course in Zeo which it seemed to have from Mr. Denning’s 
place of observation. The meteor’s real path was found to be 
from the mean radiant-point of the shower at 150°, + 23° (then 
about 60° high above the S. by E. horizon), shooting steeply 
down through 24 miles, from 70 miles over a point 8 miles south, 
to 50 miles above a point 7 miles W.N.W. from Blandford, in 
Dorsetshire, the earth-point of this course being near enough to 
Bristol (about 20 miles south) to give a nearly end-on view there 
of the swift flight, subtending only 2°, while at Slough, where 
1 Reports of the British Association, 1869, pp. 293-4. 
7 | 
NO. 1417, VOL. 55] 
Fic. 1.—Probable times, of recurrences of the Leonid meteor-shower and of its lateral branches, in 
the recent and coming years, 1894-1901; assuming the node of the meteor-orbit to have moved 
since 1866-7 with its observed and calculated mean motion. 
have been constantly, and to be still advancing at the mean rate, 
found for it by Prof. Newton and Prof. Adams, of 28’ or 297 
from a fixed, or of 57’ fromthe mean movable equinox, in each 
complete period (33+ years) of the stream’s revolutions ; so that 
the earth returns to the meteor-node in 414 minutes more than a 
true tropical year (amounting to 23 hours in a meteoric cycle), 
and in 30} minutes more than a mean Julian year. The Leonid 
showers thus recur in successive years, as the figure shows, 63 
hours later in each year than in the previous year; but the 6 
hours in this amount are corrected every fourth year, as in the 
present leap-year, by the supernumerary day, and only the half- 
hours accumulate in long times, and made the return of the after- 
stream 4 this year fall 14} hours later, on November 14, than its 
appearance 28 years ago, in 1868? (for 13 or 14 hours, from near 
midnight in Europe until after daybreak in America) on the 
morning of the 14th then ; and even shift its time of appearance 
into lasting on now, apparently through all the morning hours of 
November 15. 
No striking exhibitions this year of either the middle or the 
preceding showers A and @ appear to have been noted. At 
Slough, on the morning of November 13, only one true-pathed 
Leonid, with two from Cancer and Hydra, and three sporadic 
meteors were recorded in a sky half-clear, from 2 to 4 o'clock. 
In a watch of two or three hours on the same morning at 
Bridgwater, Mr. Corder noted twenty meteors, at a rate of eight 
per hour, and only five of these, or about two per hour, were 
Leonids. On the morning of the 14th, when the sky in England 
was generally overcast, similar numbers were observed ; by Mr. 
Corder, ina sky often foggy, thirty-three meteors being seen at 
1 Given in the discussion of those showers by Mr. B. V. Marsh, already 
cited above, in the Reports of the British Association, 1869. 
2 [bid, 1869, pp. 289-94. 
