402 
NATURE 
[ fH EBKUARY 21, 1907 
OUR ASTRONOMICAL COLUMN. 
Tue Recent Sorar Eciips—E 1N Inpia.—From a _ brief 
paragraph which appears in the Pioneer Mail for 
January 25 we learn that some interesting photographs 
of the partial eclipse of the sun were obtained at Dehra 
Dun (N.W. Prov. India) on January 14. A drop in the 
temperature of 4° corresponded with the passage of the 
shadow, and there was a very marked decrease in the 
illumination of the surrounding landscape. Venus became 
clearly visible to the naked eye. 
THE Late Dr. Roperrs’s CELesTiAL PHOTOGRAPHS.—A 
preliminary catalogue of Dr. Roberts’s collection of photo- 
graphs of various celestial objects and regions, comprising 
some 2485 original negatives, is published by Madame 
Dorothea Isaac-Roberts in No. 4154 of the Astronomische 
Nachrichten (February 9). An _ introductory statement 
which accompanies it gives a brief account of the various 
classes of negatives, the period during which they were 
obtained, and the instruments employed by the observer. 
A complete list of Dr. Roberts’s tribute to astronomy is 
to be published as soon as circumstances permit, and, as 
the number of copies of the paper will be limited, those 
interested in photographic astronomy, and desirous of 
receiving a copy, are requested to send in their names at 
once to Madame Dorothea Isaac-Roberts, Chateau Rosa 
Bonheur, By-Thomery, S.-et-M., France. Positives on 
glass reproduced from the Isaac-Roberts negatives will 
be lent for the purpose of micrometric measurements if 
application be made, and provided that the documents be 
returned after the completion of the measurements. 
A Lost Comer (1905f).—Whilst examining three photo- 
graphs taken at Mount Wilson on July 22, 1905, Prof. 
Barnard found the trail of a comet which appears to have 
evaded all other observations, and, as the object might 
prove to be a periodic comet, he now publishes some 
measures of position which he has made in order to deter- 
mine, if possible, an approximate orbit, in No. 4153 of 
the Astronomische Nachrichten (February 6). ¥ 
The positions (1905-0) of the comet at the beginning and 
end of the trail were :— ; 
R.A.=18h. 23m. 16-4s., 
at 16h. 20m. G.M.T., and 
R.A.=18h. 23m. 41-2s., 
5=— 20° 31’ -9, 
at 18h. 55m. G.M.T., respectively ; the position angie and 
length of the trail were found to be 288° 24’ and 368", 
thus giving a daily motion amounting to 3m. 4o:s5s., 
—17'55". On examining the Harvard plates for this 
date, Miss Leavitt was unable to find any trace of the 
object, which must have been much smaller than 
Giacobini’s 1905 III. comet, and at least six or eight times 
less bright. 
THe SpectRuM or Mira.—Four photographs of the spec- 
trum of Mira were obtained at the Lowell Observatory 
during the recent maximum of the star’s brightness, and 
a_ brief discussion of them is published by Mr. V. M. 
Slipher in No. 1, vol. xxv. (February), of the Astrophysical 
Journal. The first spectrogram, obtained on December 
13, 1906, included the region A 4300 to A 5000, and shows 
both Hf and Hy as strong, bright lines. The second 
photograph was taken on December 18, and shows the 
four hydrogen lines Ha, H8, Hy and Hé as bright lines 
increasing in intensity in the order given, Ha being notably 
weaker than the others. Numerous absorption bands, 
sharp and intense on their more refrangible edges, and 
gradually fading out towards the red, are shown, in 
addition to the hydrogen lines, on the plate taken on 
December 21. On the last plate taken, December 24, all 
the hydrogen lines were bright, Ha being bordered on the 
violet side by a strong and rather broad absorption line. 
Of the metallic absorption lines, those due to vanadium 
are recorded as being especially strong. 
Sun AND Praner Cuart.—We have received, from the 
firm of Carl Zeiss, 29 Margaret Street, W., a copy of a 
very useful chart which enables a ready determination to 
be made of the position of the sun, or of any of the 
planets, in regard to the fixed stars during 1907. It con- 
sists of a chart of the equatorial constellations, together 
NO. 1947, VOL. 75] 
with right ascension and declination curves, on the same 
scale as the chart, of the objects to be found. By simply 
drawing ordinates for the required date, as found on the 
chart, and projecting the points where they intersect the 
R.A. and declination curves on to the star chart, the 
relative position of the sun or planet may be determined 
in Jess than one minute. 
Tuirty-six New Variable Srars.—By superposing posi- 
tive and negative copies of six photographs taken with 
a 1-inch Cooke lens, Miss Leavitt discovered thirty-six 
new variable stars in a region 30° square, having its centre 
at R.A.=12h., dec.=—60°. These variables are mostly 
situated in the constellations Carina and Centaurus, and 
six of them are probably of the Algol type. Nova Velorum 
was discovered, and sixteen known variables were re- 
discovered on the same plates (Harvard College Observatory 
Circular, No. 122). 
SEISMOLOGICAL NOTES. 
Valparaiso Setsmograms. 
ON August 17, 1906, Valparaiso was visited by an 
earthquake of unusual severity. Seismograms of this 
disturbance were obtained at all observatories throughout 
the world which were properly equipped with apparatus to 
record teleseismic motion. The seismograms obtained in 
this country, as was pointed out to me by Mr. R. D. 
Oldham, and noted by other observers, exhibit a dual 
character. This duality is clearly seen in the annexed 
seismogram from Kew, reproduced by the kind permission 
of Dr. R. T. Glazebrook. After preliminary tremors, there 
is a ‘‘shock’’ or maximum, marked A, at 1.5 G.M.T., 
and a second ‘ shock ’’ or maximum, marked B, forty- 
five minutes later, or at 1.50. If the latter shock origin- 
ated in or near to Valparaiso, and took th. 5m. to travel 
from that part of the world to Britain, it originated there 
at 7.59 in Valparaiso time. The most accurate time re- 
ceived from Santiago is 7.58.40, or practically 7.59. We 
may therefore conclude that B represents the disturbance 
which led to devastation in Valparaiso and places in that 
vicinity. The question now arises as to what is shock A at 
1.5 G.M.T. From the duration of its preliminary tremors, 
it evidently came from some place about 105° distant, 
which happens to be the situation of Valparaiso, and the 
time of its origin, wherever that may have been—Central 
Asia or South America—was in G.M.T. oh. om. (7-14 
Valparaiso time), but up to date I am not aware that the 
inhabitants in Valparaiso know anything about a shock 
at 7.14. Shock A and shock B may have a direct relation- 
ship, or they may he independent disturbances which 
occurred about the same time. Together they make a 
jumble which might be compared with the meeting of 
waves at the mouths of two opposing estuaries. The Inter- 
national Seismological Association, which met last year in 
Rome, issued from its headquarters in Strassburg a 
circular to seismological stations generally asking for 
seismograms of ‘‘ the Valparaiso earthquake.’’ These and 
a variety of detail about instruments and the stations where 
seismograms were obtained are to be placed before the 
delegates of that association when they meet at the Hague 
for their study. 
A New Seismometer. 
The International Seismological Association offers prizes 
of sol., 35/., 25/., and 15]. for the construction of a seismo- 
meter. It is to record earthquakes which have their origin 
near to the place of observation, which we assume means 
earthquakes that can be felt. It must register both hori- 
zontal and vertical movements. No doubt the authors of 
this condition are well aware that vertical displacements 
are accompanied by angular displacements. Any recording 
seismometer under the influence of vertical movement at 
its best becomes an indifferent variety of clinometer. 
Usually its records have no more value than those from 
a seismoscope. One remarkable condition is that the new 
instrument must have a magnification of not less than forty 
to fifty times. Seismographs used in Japan, and by all 
who have had experience in recording earthquakes of local 
origin, find a magnification of ea six to ten quite 
sufficient. If a shock has a range of a quarter of an 
inch, which in soft ground may well be the case, this 
