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The eastern branch was fainter than the western, and at mid- 
night it was seen from y Virginis, near the horizon, up to Pre- 
sepe in the zenith, as a broad and tapering cone of light. 
Hence the zodiacal light, when seen in perfection, consists of 
two cones of light, whose common axis is the Ecliptic, and 
whose common vertex isa point on that axis almost exactly 180° 
from the sun. The fact that the western branch is brighter than 
the eastern also confirms my idea of its origin, the brighter 
branch being over the warmer portion of the earth’s surface ; 
but I hope to make more observations of its breadth at different 
times of the year before writing more on this subject. 
Jamaica, Feb. 6 MAXWELL HAL 
[We hope our correspondent will continue to send us more of 
his interesting and valuable letters. It isindeed a great gain to 
scienceto have an observer stationed on the vantage ground 
which he occupies. —ED.] 
As no one has replied to Maxwell Hall’s letter on the zodiacal 
light (vol. vii. p. 203), I might state that his theory that the earth 
has two tails which stretch to an indefinite distance away from the 
sun is not in accordance with observation, for I have often seen 
the zodiacal light 180° off the sun. This is no proof against 
M. H.’s other idea that the two tails curve round and meet ; but 
is there anything in M. H.’s observations contrary to the gene- 
rally received theory of the zodiacal light? This is that it is not 
aring, but a somewhat lens-shaped disc of light, brightest and 
thickest at its centre (at the sun), and gradually growing thinner 
and less dense, till it seems io vanish some distance beyond the 
earth’s orbit. Its thickness at its centre would therefore be 
60,000,000 miles, or more, according to M. H.’s observation. 
The circumstance that he could not see it more than 177° off the 
sun might very likely be accounted for by the milky way obscur- 
ing it there. T. W. BACKHOUSE 
West Hendon House, Sunderland, Feb. 10 
The Meteoric Shower 
THE shower of meteors on the night of Nov. 27 last year was 
evidently well seen in Europe, as I had anticipated, but no 
notice seems to have been taken of the shower on the night of 
the 24th. On that night there was an equally fine display in 
Jamaica, from about the same radiant point; the night of the 
25th was cloudy, and only a few meteors were seen on the night 
of the 26th, which was clear ; and the shower on the 27th was 
simply a repetition of the shower on the 24th; but on both 
occasions the numbers seen here were somewhat less than in 
Europe. 
These meteors must therefore form two almost distinct bands 
passing round the sun, which their association with. the comet 
of Biela renders particularly interesting ; it is just possible that 
these two bands intersect, and that one part of the comet belongs 
to one band and the other part to the other, and that they 
came into notice and actual contact about the same time in 
the year 1846, and of course afterwards separated. 
Jamaica, Jan. 5 MAXWELL HALL 
Maupertius on the Survival of the Fittest 
CoNnSIDERING that the theories of Darwin and Spencer are 
among the most important additions ever made to human know- 
ledge, it seems to be a matter of much interest to trace out any 
occasional glimpses which previous philosophers may have had 
of the Principles of Natural Selection. Ina long note appended 
by Lord Bolingbroke to his fourth essay concerning Authority 
in matters of Religion (octavo edition of the Philosophical 
Works, 1754, vol. ii, p. 253; quarto edition, 1754, vol. 
iv. p. 255), he reviews a Memoir by Maupertius printed 
in the History of the Royal Academy of Berlin, for the year 
1746. Speaking of the appearances of design, Lord Boling- 
broke says :—‘‘ Mr. Maupertius proceeds, and admits, but ad- 
mits, as it were, for argument’s sake alone, that the proportion 
of the different parts and organs of animals to their wants carries 
a more solid appearance ; and he judges that they reason very ill 
who assert that the uses to which these parts and organs are ap- 
plied, were not the final causes of them, but that they are so 
applied because the animal is so made. Chance gave eyes and 
ears ; and since we have them we make use of them to see and 
hear. He thinks, however, it may be said, that chance having 
produced an immense number of individuals, those of them whose 
parts and organs were proportioned to their wants, have sub- 
sisted, whilst those who wanted this proportion have perished 
and disappeared. Those who had no mouth, for instance, could 
not eat and live; those who wanted the organs of generation 
could not perpetuate their species ; and thus from the present 
state of things theists draw an argument which will appear falla- 
cious when it is applied to the possible original of things.” 
I am not aware that notice has been drawn to this distinct 
allusion to the survival of the fittest. So far as regards the intro- 
duction of the notion of chance the statement is no doubt erro- 
neous. W. STANLEY JEVONS 
Manchester, Feb. 12 
** Diathermanous” or ‘‘ Transfervent ” 
THE words ‘‘ transfervent” and ‘‘transfervency ” are similar 
in form to ‘‘ transparent” and ‘‘ transparency,” and clearly con- 
vey their meaning to those who cannottrace them to their source. 
In number of syllables, also, and in sound are they not more 
English, or as a Greek might say, less barbarian than words of 
five, six, or seven syllables which are coined directly from the 
Greek, but which do not suit so well the Saxon tongue ? 
W. G. ADAMS 
Flight of Projectiles— A* Query 
I SHALL feel thankful to any of your numerous mathematical 
correspondents who will kindly favour me with a simple formula 
for determining the deflection in the flight of a leaden cylindro- 
conoidal projectile—the time of flight of which is known— 
caused by wind of known force acting at different angles to the 
vertical plane of the trajectory, with an application of the formula 
to the following cases. Any other cause of deviation, such as 
that due to rotation, &c., may be neglected :— 
Suppose the bullet to be 1°27" long, and its diameter +447”, 
weight 480 grs. and the wind to be of force 4, approximate 
pressure 4 lbs. per square inch, what is the deviation? 
1. When the wind acts at right angles to the trajectory ? 
2. When it acts at any angle less than a right angle, say 45°? 
Robert REID 
School of Musketry, Hythe, Feb. 10 
ON ACTION AT A DISTANCE* 
Ve have now arrived at the great discovery by Orsted 
2 of the connection between electricity and magnetism 
Orsted found that an electric current acts on a magnetic 
pole, but that it neither attracts it nor repels it, but causes 
it to move round the current. He expressed this by 
saying that “the electric conflict acts in a revolving 
manner.” 
The most obvious deduction from this new fact was 
that the action of the current on the magnet is not a 
push-and-pull force, but a rotatory force, and accordingly 
many minds were set a-speculating on vortices and streams 
of zther whirling round the current. 
But Ampére, by a combination of mathematical skill 
with experimental ingenuity, first proved that two electric 
currents act on one another, and then analysed this action 
into the resultant of a system of push-and-pull forces be 
tween the elementary parts of these currents. 
The formula of Ampére, however, is of extreme com- 
plexity, as compared with Newton’s law of gravitation, 
and many attempts have been made to resolve it into 
something of greater apparent simplicity. 
I have no wish to lead you into a discussion of any of 
these attempts to improve a mathematical formula. Let 
us turn to the independent method of investigation em- 
ployed by Faraday in those researches in electricity and 
magnetism which have made this institution one of the 
most venerable shrines of science. 
No man ever more conscientiously and systematically 
laboured to improve all his powers of mind than did 
Faraday from the very beginning of his scientific career. 
* Continued from p. 325. 
