AUGUST 19, 1915] 

Bose’s figure. We have made the necessary additions, 
and find a biquadratic, as was anticipated. But a 
more unfortunate circumstance is that the author 
makes the variations in the components of the tension 
of the kite string depend on the velocity components of 
the Kite instead of on the angular displacements. It 
is to be mentioned, however, that the investigation is 
independent of the assumption that the surface of the 
kite is a narrow plane gliding at a small angle of 
attack, an assumption sometimes justifiable in the case 
of an aeroplane, but inapplicable to the old-fashioned 
quadrilateral kite. 
THE Psychological Bulletin for June 15 contains 
several summaries of recent work in the different de- 
partments of sense perception, One of them deals 
with the factors which influence the estimation by an 
observer using one or both ears of the position of the 
source of a regular sound such as a musical note. For 
a person using one ear only Arps and Klemm have 
confirmed the belief that some factor besides the 
intensity of the sound heard plays a part in the esti- 
mation of the distance of the source. Myers has 
shown that the timbre of a note is one of the factors 
which affects the estimation of distance of a source 
in the hearer’s median plane, but not in any other 
direction. Another summary deals with optical illu- 
sions, amongst others with that of two or more parallel 
lines, one of which when crossed obliquely by short 
lines no longer seems parallel to the others 
—Zollner’s lines. Giese has shown that if one line 
only of a pair of parallel lines is crossed by oblique 
lines, the extent of the illusion is half that when 
both lines are crossed when one eye only is used, but 
that when both eyes are used the illusion is the same 
in each case. If the figures are presented in succes- 
sion instead of simultaneously, the extent of the illu- 
sion is diminished. Practice also decreases the 
illusion. 

OUR ASTRONOMICAL COLUMN. 
AuGcust Merrors.—Mr. Denning writes :—‘‘ Very 
unsettled weather, with thunderstorms unusually pre- 
valent, has interfered with observation of the Perseids 
this year, but a fair number of them were recorded. 
The display appears to have been one of average 
character. 
“On August to the sky was only partly clear at 
some places. There were about 20 meteors per hour 
(14 Perseids) for one observer watching uninter- 
ruptedly. 
“On August 11 clouds were more abundant, and 
not much could be seen of the shower. 
““On August 12 the sky was very favourable in the 
west of England, but somewhat clouded in the east. 
At Bristol 80 meteors (68 Perseids) were seen up to 
12.30 p.m., but many others were missed, and the 
horary rate for a constant watch of the sky would 
have been about 4o. 
“On August 13 there were some passing clouds, 
but up to midnight these did not materially affect the 
progress of observation. At Bristol 45 meteors (29 
Perseids) were counted. The number had evidently 
decreased since August 12. 
“On August 14 several thunderstorms 
during the night, and nothing could be seen. 
NO. 2390, VOL. 95] 
occurred 
NATURE 




683 
“The radiant point of the meteors was as 
follows :— 
July 15 15 + 48 
August 10 40+55 
August 12 47 +58 
August 13 49+58 
Nearly all the meteors left strealxs. 
‘The most brilliant object appeared on August 13 
1th. 8m., shooting from 344°+50° to 253°+453°, 
where it left a streak for 30 seconds as seen from 
Bristol. It was seen at Bristol, and by Mrs. Wilson 
at Harrow. Its radiant point was at 54°+56°, and 
height 79 to 55 miles, path 48 miles, and velocity 
40 miles per second. It moved from over Northamp- 
ton to Oxford. 
‘““A curious meteor was recorded on August 12 
toh. 44m., shooting upwards from 303°+20° to 
13°+51°. It moved slowly, and left a bright streak. 
Half-way along its course it appeared to stop, and 
then renewed its course. 
“The radiant of the Perseid swarm was fully four 
degrees in diameter. 
“Large meteors were not very abundant, but 
several were noticed, and will be made the subject 
of further investigation. Several of them were 
recorded by two or more observers. 
“Mrs. Fiammetta Wilson at Harrow-on-the-Hill, 
and Miss A. Grace Cook at Stowmarket, obtained a 
number of valuable observations, though the atmo- 
spheric conditions were seldom very good. It will be 
possible to compute the real paths of many large 
meteors (Perseids) and of several meteors directed 
from the minor radiants of this period. Mrs. Wilson, 
with her usual perseverance, has sent the writer a list 
of 110 meteor-paths observed from August 7 to 15. 
“One of the most interesting objects that has 
appeared during the recent display was a brilliant one 
from Musca (40°+29°) on August 10 at gh. 33m. 
The meteor had a long path of about 154 miles from 
over London to the English Channel east of Start 
Point, Devonshire. It fell from a height of 68 to 
52 miles. 
““A feature noticed in regard to the Perseids was 
that they exhibited a distinct difference of velocity. 
This was quite apart from such discordances as might 
be induced by differences in position and distance. 
Two meteors appearing in very nearly the same region 
gave in several instances an apparent speed essenti- 
ally dissimilar, though presumably at same height, or 
very nearly so.” 
Tue Derroir OsserRvaTory.—We have _ received 
vol. i., pp. 73-206, of the Publications of the Astro- 
nomical Observatory of the University of Michigan, 
which forms an impressive testimony to the activity 
of the staff. Thus, in about four years, no fewer 
than 3200 spectrograms have been secured with the 
37s in. reflector, and meanwhile the Director has 
found time to organise and direct the work of the La 
Plata Observatory, which has already made a mark 
in cometary discovery. The long-projected Lamont 
24 in. refractor, it is to be regretted, is still delayed, 
awaiting the delivery of the flint glass disc from the 
Jena makers. 
The astronomical researches described in the pre- 
sent volume include determinations of the geo- 
graphical position of the observatory, the visual light 
curve of 8 Lyrz, a paper on the characteristics of 
Cepheid variables, and studies of the spectra of 6 and 
e Orionis, all the work of Prof. Ralph H. Curtiss; 
the spectra of y Persei and £8 Monocerotis, and 
radial velocity of Maia, treated by Dr. Paul Merrill; a 
study of the titanium spark as a comparison spectrum, 
