eS emeeeensl 
April 24, 1873) 
NATURE 
483 
these radiated from near a Lyre, or from a point at R. A. 274°, 
D, 37+. The following are the details :— 
~ Date. Time. Beginning. Ending. 
‘ R.Ayeee ROA OD. 
April 19... .. 9.28 rst mag. * 295°} 46°+ 316°  51°+ 
a we «w. 10.3% 2ndmag. * 305 38+ 309 373+ 
Bs wwe oe 10.43 3rd mag. K 277. 36+ 2788 35 + 
Fe ae os 10.50 4th mag. * 256 7 + 254 34+ 
April2o.. .. g.ro 3rd mag. * 266 w+ 2644 3134 
» oe « 9.50 3rd mag. * 319 45 + 329 45 + 
» ws ow 35.4 |ondmag. * 282 92-4 285 16 + 
a ws oe 12.13 2nd mag. * 2644 16+ 261} 9+ 
The other four showed a well-marked radiant point at R. A. 
221°3, D. 20 + in Bootes. The observed paths of these were as 
under :—- 
Date. Time. Beginning. Ending. 
R.A, D. RAS =D: 
Aprilig .«. «. 9.58 and mag. * 307% 43°+ 285° 33°+ 
April20 .. .«. 99 3rd mag. * 247 28+ 258 29 + 
ns on 9.54 1} mag. * 244 53 + 268 67 + 
» eee eee 10255 St mag. *K 225 19+ 246 16 + 
The brightest meteor seen was one that appeared at gh 28™ 
on April 20. It diverged from the radiant in Lyra, and was 
about equal in brilliancy to @ in that constellation This 
meteor left a train which remained visible about 1} sec. after the 
disanpearance of the head. 
Bristol, April 21 WiLiiaM F. DENNING 
IsenD the following observations of the shooting stars of 
the April period, viz., the 19th and 2oth. On the 19th I 
began to watch at rol, but saw no more until 11.45. I then 
watched them until 34 15™. I found they seemed to come in the 
region of the heavens about Corona, so I confined my obser- 
vations to that part as I had not a situation where [ could see 
the opposite side as well By 10 0’clock Hercules was quite 
above the buildings, so there may have been some meteors 
visible earlier, when these constellations were too low for me to 
see. The first night they were all comprised in a triangle, 
which wouid be formed by a line stretching from Vega by way 
of Ophiuchus to Mars, and thence up to Arcturus and by Corona 
back to Vega. They were pretty equally distributed over this 
region. The next night they were much more concentrated in 
Ophiuchus and Hercules and towards Libra. I was not able to 
determine the radiant, so I confined myself to reckoning them 
accurately in intervals of fifteen minutes, which time I had conve- 
niently marked for me by the church clocks, and only observed 
their tracks approximately. On the second night I noted the po- 
sition and direction of each which shows their concentration about 
the part named. On the nineteenth there were 25—15 horizon- 
tal, 10 vertical. On the 20th from 9.45 to 2.45 there were 33— 
22 vertical and 1% horizontal. hose I call vertical by distinction 
were almost all just half way between horizontal and vertical, 
z.e. atan angle of 45°. It was curious how this angle predomi- 
nated. It was also curious that the first night the horizontal 
ones predominated, and the second night the vertical. I do not 
know if I am wrong (I) in assuming that we pass through the 
node of the orbit of the meteors at this time, and (2) in inferring 
from this assumption that the angle at which they principally 
appear to us would be a guide to the inclination of the node. 
Would the fact of their being horizontal be any proof that the 
inclination of their orbit is small, and their being vertical a 
proof that it is much greater, and of a somewhat similar angle? 
But this would not explain the fact of the majority being hori- 
zontal the first night and the majority at a greater angle the next 
night. One seen on the 20th was intermittent, it ran for a long 
distance, and became visible at intervals of a few seconds a little 
way iurther on. Only a few were of any size, and the first 
night all but two were extremely small and very faint, with very 
short tracks. The next night they were not only greater in 
number but larger, brighter, and with longer tracks. A few 
left tracks lasting a second or two. One only moved very fast. 
The first might there was one quite vertical upwards. This was 
the only instance. The majority were from E. to S. or E. to W. 
on both nights ; and the only two of any length on the 19th were 
one running out of Corona and one running into it. It seemed 
curious to me how these should be so much longer than all the 
others and yet lie so close to the point of apparent divergence of 
them all. The following is a list for the two nights of the num- 
ber in each 15 minutes: April 19.—From 11.45 to 12, 2; 
E2505, 5's E230) 202 45, 2 5-13, 1 3'13-LG be A s30 1550345, 
O} 14, 33 14.15, 25 14.30, 03; 14.45, 15 15, 15 15 1015.30, 0; 
Total ; 25. 
April 20.—From 9.45 to 10, 1; 10.15, 3; 10.30, I ; 10.45, 0; 
TT) 5 ELS, 23 LI. 30, 23 Baby. ty 12, Ob tearho ts L2r3Q, 
15 12.45, 15 13, 23 13-15, 45 13.30,23; 13.45, 2; 13.45 to 
Mego. 14.45, 5; Total ; 33. P. BL 
att 
Instinct 
A Mechanical Analogy 
Mr. Darwin, in his article on ‘‘ The Origin of certain In- 
stincts,” in NATURE, of April 3, appears inclined to think that 
what we may call the instinct of direction in animals is of the 
same kind as the faculty by which men find their way: and he 
instances the power of the natives of Siberia to find their way 
over hummocky ice. He afterwards, however, raises without 
discussing the question ‘‘ whether animals may not possess the 
faculty of keeping a dead reckoning of their course in a much 
more perfect degree than man, or whether this faculty may not 
come into play on the commencement of a journey when an 
animal is shut up in a basket.” I wish to point out that this 
peculiar power of animals is one that cannot be explained 
as a higher degree of any power that man possesses. What man 
can do is to find the third side of a triangle after travelling the 
other two sides with his eyes open. Animals can do the same 
after travelling the two sides with their eyes shut. The former 
power does not in any degree involve the latter. Moreover, the 
power of man here spoken of depends on the careful use of his 
powers of observatin. This does not appear to be the case 
with animals. Among the many instances of animals finding 
their way home after being conveyed away without any oppor- 
tunity of seeing their way or taking their bearings, there must in 
all probability be many in which the animal slept on the jour- 
ney : and if so, the mental or organic process whereby it was 
able to know its way back must have gone on during sleep. 
There is nothing in man’s mind similar to such a process as this. 
It on be made conceivable only by a mechanical analogy, if. 
at all. 
If a ball is freely suspended from the roof of a railway carriage, 
it will receive a shock sufficient to move it, when the carriage is 
set in motion: and the magnitude and direction of the shock 
thus given to the ball will depend on the magnitude and direc- 
tion of the force with which the carriage begins to move. While 
the carriage is in uniform motion the ball will be relatively at 
rest ; and every change in the velocity of the motion of the 
carriage, and of its direction, will give a shock of corresponding 
magnitude and direction to the ball. Now, it is conceivably 
quite possible, though such celicacy of mechanism is not to be 
hoped for, that a machine should be constructed, in connection 
with a chronometer, for registering the magnitude and direction 
of all these sh icks, with the time at which each occurred ; and 
fiom these data—the direction of the shock indicating the direc- 
tion of the motion of the carriage, the magnitude of the shock 
indicating its velocity, and the interyal of time between two 
shocks indicating the time during which the carriage has run 
without change of velocity or direction—from these data the 
position of the carriage, expressed in terms of distance and 
direction from the place from which it had set out, might be 
calculated at any moment. The automatic register of the jour- 
ney may be conceived as exacily resembling the records of the 
velocity and direction of the wind produced by one of Robinson's 
or Beck’s self-registering anemometers, where one pencil-mark 
indicates the direction of the wind,at any past hoar, and another 
its velocity. 
Further, it is possible to conceive the apparatus as so inte- 
grating its results as to enable the distance and direction of the 
point where the journey began to the point it has reached, that 
they can be read off, without any cal.ulation being needed :— 
a hand on a dial pointing to the direction expressed in degrees 
of the circle, and the distance being shown in figures expressing 
miles and decimals of a mile. 
Now, I suppose such an integrating process as this (though of 
course not by any similar mechanism) to be eff-cted in the brain 
of an animal unconscivusly, and that the animal has the power 
of reading off the result—that is to say, bringing it into con- 
sciousness when wanted. JostPH JoHN MurPuy 
Old Forge, Dunmurry, co, Antrim, April 11 
Sense of Orientation 
Your article on this subject in the issue of March 20, insists 
very properly on the objecuion to Mr, Wallace’s theory that “ir 
it be solely by the aid of this memory of smells that the dog is 
