The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1900-11-11
sequenuy the direction. Of the I.eonid

Some of the Photographic appliances tt
| be used-always supposing the swarm re
| appears-have been especially devised fol
the occasion. The most remarkable, per
| haps, is swinging camera, for securing
/ stationary images Of the Leonids 1t Is
ike the swing of a pendulum-in state
| of balance at either end; moving faster
| comparatively, than the shooting star al
] the middle, but at some point between,
on the rise or the fail, exactly CORE
| spending to the velocity of the object
| which 1t is all this time photographic.
| Besides getting the image at rest In this
| way, 1t will be easily possible to calculate
| the speed Of the meteor by aScertaining
the position of the camera in its swing
| when that image was secured.
Another interesting instrument Is fitted
! with prisms to photograph the spectra of
! the LeonidS, from which II will be posi-
bic to learn their composition. The only
spectrum of a shooting star ever secured
by photography was obtained at the Ear-
ward station at Arequipa four years ago,
and shows by it's lines the. presence of
hydrogen. Still another Photographic in
suument has a rotating disc over the
aperture. revolving thirty times a second
In the disc is a hole which, passing over
! the aperture, records the. path of the
meteor in "a series of dots. Any differ
ence In the distance between the dots
.ethO dI1 lilOlCI3tlDll VI d -dlllt5l SIlC6
in the rate Of movement ofathe meteor.
The preparations at the Harvard Obser-
! Xatory last year were on a very extensive
scale, and covered a number OF stations
three in the vicinity Of Providence. r. l.,
and two, including the Observatory itself,
near Boston, The plan for the work in
Cambridge was an admirable example of
the way astronomers are able to system
atlze difficult and complicated observa-
tons, and will be followed, If opportunity
offers, next week. Aside from those in
charge of the photographic, the staff
VIII be divided into counters, time-keep-
ers, recorders, cloud observers ito note
interruption In the observations, and
draughtsmen.
The matter OF time is, of course, most
important. gong will strike automati-
cally every ten, minutes, SO as to afford a
constant check on the observations At
the beginning Of observation the counters
Will have stationed themselves to watch
the portion of the sky containing the con-
/ stellation OF the Lion, and count the
meteors as they appear. while the time
! Keepers note the time of each as exactly
as possible-a difficult undertaking. when
| 1t Is remembered that the mateors may
! possibly fall at the rate of over fifty q
minute. The record Will. serve to iden-
] TRY all, or at least great many. of the
meteors by serial number and the time
recorded.
The general observers will look for
! special features, like the magnitude col
or, whether the stars explode or not, and
whether trail appears. A general OBJ
server, for example, may note that the
/ ll2th meteor marked by the counter was
yellow and left a trail lasting ten sec
J ohds' and that its path was from near
some standard star to another standard.
his notes can be compared later with
the observation sheets Of the other OBJ
servers. With each general observer
Will be a recorder, to note according to a
code the phenomena which he announces.
The draughtsmen will be supplied with
maps Of the region around the constella-
ton Leo, and they will draw the path as
well as possible Of each notable meteor.
The direction and line of 1.-The 10Th
meteor, for instance, its brightness and
the character of its trail, are useful facts.
The matter Of brightness necessities the
quickest obserEa ton, which offers. how
ever, no special difficulty when one has
nothing else to attend to. The scale
adopted IF one may go into technical
details for a moment) Is to assign a mag
nitude Of minus 2 to a meteor a little
brighter than Sirius or Jupiter; 0. If
equal tosGapella; 2, If equal to Gamma
Leonis, the bright star in the blade OF
the Sickle, which stands out clearest in
tiiG COitSlS4Id t4Otl Leo q, II equal to MU
LeorAs, the second next star to Gamma
in the Sickle; 5, to faint meteors gen
orally. - tsys
A year ago, the Harvard Observable
asked for the cooperation of observers
all over% the world-not only astrono
mers, but intelligent Iaymen everywhere
and full circular of rules to govern
such observers was sent out by the Uni
yersity.E The most Important part of tie
circular Is al f01I0Uys
The most important time for observa-
ton is from midnight until dawn, as com
paratively few meteors are expected
earlier Observations are particularly
needed at Hours when they cannot be
made at the obserVatories of Europe and
america. In general, the time REQUIRED
for ter or more meteors to appear in the
region covered by-the-a &C oHnpanylng man
should be recerTed, e This observation
should be repeated every hour zor half
hour. II the meteors are too numerous
| TO count all those appearing upon tha
| map, the observer should cenffne his ar.
tentlon exclusively to some small region.
| such as that included between the sta re
| Mu Ursae MAJORS, 40 Lvncis. and Deli.
and Alpha Leonis. If the meteors occur
put seldom one every five minutes for
instance the time and class Of each me-
| teor should be recorded Also motto +be
time during which the sky was watched
ana no meteorS seen, and the TINA. d,r
| ing which that portion of the sky wa
| obscured by clouds. Passing clouds or
haze, during the time Of observation
should also be recorded. The date should
be the astronomical day, beginning AT
noon; that is, the date Of early morning
observations should be that of the IRE.
ceding evening. Specify what time is
usedS as Greenwich. Standard, or Local
| time. When a meteor bursts. make q
| second obserVat ton Of its light and. color
| and, when it leaves trail. record tbe
motion of the latter by cf1artino tbo
I ne1ghboring stars, and sketchfne it's ,osl
ton among them at short intervals mt,
! 1t disappears, noting the time of each
! observation. If the path of a meteor ,s
surely curved, record it carefully uno1
| the map
! Photographs may be taken fret hv
leaving the camera at rest, when the
images of the stars will trail over the
! plate and appear as lines or. secondly ~
| tachlrg the camera to an equatoriaI +e1o
scope moved by clockwork, when a. chs -,
/ OF the sky will be formed, in which 49,
/ stars will appear as points. A raDid-rec1
uHnear lens is to be preferred in the fire,
case, wlde-ang!e lens in the SECOND
Inc 1uli aperture should be used and &c
! large plate as can be covered rrbe
| most rapid plates are best for this work
they should be changed once an hour. and
the exact times of starting and stonnino
recorded. Care should be taken to stiffen