348 
NATURE 
a sheet of white paper held parallel to the card and 
at right angles to the rays. Take a pin with a round 
head of black glass, of a diameter very little less 
than the hole in the card, and, holding it about an 
inch from the card, pass it very slowly across the 
hole. The bright image of the sun will then pass 
through all the stages of an eclipse, commencing 
with the “first contact’? as the head of the pin first 
emerges into the rays at the edge of the circular disc 
of light, and forming all the successive crescent 
phases until it lies co-axially with the hole in the 
card, when the appearance of an “annular eclipse” 
is reproduced. Further movement of the pin in the 
same direction will reproduce the phases which occur 
after totality has been reached, giving, finally, the 
phase of ‘‘last contact.” 
If the bright annular ring of light be examined 
carefully when the ‘‘eclipse"’ is at its maximum, it 
will be seen to be free of blurs or blemishes if the 
edges of the hole and the head of the pin are both 
clean and free from projecting particles. Now coat 
the head of the pin with fine dust, such as flour or 
the pollen of a flower—even fine tobacco ash will 
suffice—and repeat all the above operations. No 
roughness, or only a very little, will be seen on the 
dark image of the ‘‘moon"—the pin’s head—until 
the annular stage is reached, when quite suddenly 
there will appear black spots and streaks in the 
bright ring of light, giving one the impression that 
“Baily’s beads” have been produced. Whatever 
may be the true cause of this latter phenomenon 
during an annular eclipse of the sun, such as was 
witnessed on April 17 last at some places, the effect 
in the experiment above cited may be produced in 
one of three ways: first, by roughening the surface 
of the pin’s head; secondly, by dust on the edges of 
the hole; thirdly, by both the causes stated in the 
first and second cases acting simultaneously. 
W. G. Royar-Dawson. 
17 Pembridge Gardens, W., May 27. 
Solar Halos on May 17. 
Tue set of halos described by your correspondent 
(NaturE, May 30) was also seen in London at the 
same hour. The inner one had a radius of about 
22°, measured by the rough method of holding a 
stick at arm’s length, and the outer one, of which 
only 60° or 70° were visible on the east, of approxi- 
mately twice this angle. 
Again on May 19 the inner halo was seen, and on 
May 27 both inner and outer, at approximately the 
same hour. To meteorologists it may be of interest 
to note that after none of these three dates did bad 
weather follow, as is usually expected. 
The above values (22° and 46°) for the radii of 
the two halos are in accordance with the accepted 
explanation that they are due to refraction through 
ice-crystals, these being the angles of minimum 
deviation through prisms of 60° and 90° respectively, 
the refractive index of ice being taken as 1-31. About 
one point of the explanation of the text-books I should 
like to be allowed to ask a question. The tangent 
are at the vertex of the halo, the mock-suns on the 
horizontal line through the sun, and the sun-pillar 
are said to be due to. particular orientations of the 
ice-crystals being preponderant, that of laminate 
erystals with their axes horizontal and that of needles 
with their axes vertical. Perhaps someone that 
knows will be good enough to say whether these are 
possible positions of equilibrium of such bodies fall- 
ing through air. : C. O. Bartrum. 
32 Willoughby Road, Hampstead, May 30. 
NO. 2223, VOL. 89| 
[JUNE 6, 1912 
Earthquake of May 23, 
THE recent earthquake, reported as severe in 
Burmah, has left its record on our Milne seismo- 
graph by a displacement of the boom nearly as 
great as on January 3, Ig1I. On that date all the 
three needles of the magnetograph were shaken by 
the earth wave, and notably that of the horizontal 
force, of bifilar suspension. On the recent occasion 
of May 23 we find no indication of any mechanical 
disturbance of the needles. In the former waves the 
vertical movements must have been much more pro- 
nounced than on May 23.- 
The first tremors arrived here on May 23 at 
2h. 36.6m, a.m., thirty-six minutes before the greatest 
swing of the boom, and this interval indicates on 
Milne’s curve a distance of 56°—considerably short 
of Burmah. May it be that this was the trigger to 
start a stronger movement nearer to us, itself too 
weak to leave the mark of its first preliminaries on 
our films? This would be an illustration of the 
secondary earthquakes referred to by Milne in his 
Sixteenth Report of Seismological Investigations, 
p. 3 (from the British Association for the Advance- 
ment of Science, Portsmouth, 1911). 
W. SIDGREAVES. 
Stonyhurst College Observatory, May 28. 
Anatomy of the Bee’s Sting. 
DurinG a recent inquiry into the existing know- 
ledge of the chemistry of bee poison, I examined also 
the anatomy of the bee’s sting, a subject to which I 
venture to direct attention, It is stated, and the 
evidence seems to be undeniable, that the sting of 
the worker bee is the insect’s ovipositor metamor- 
phosed into an efficient weapon of attack. On the 
basis of the principles of evolution, it would be said 
that the conditions, producing the specialised activi- 
ties of the worker bee required, also the change 
indicated. By inference, obviously, one must turn 
to the queen bee, whose existence is justified 
solely by her egg-laying capacities, and who may 
have been specialised in this direction—an opposite 
one to that of the worker. But here, too, is found 
the same metamorphosis to an almost equal extent, 
so that it would seem, considering that the genital 
opening is below the base of the sting (itself the 
original ovipositor), that stinging was of vastly more 
importance to the queen bee than egg-laying. But 
since the queen employs her weapon a few times 
only during her life, this suggestion falls to the 
ground. The only other explanation seems to be 
that at a certain stage in the evolutionary develop- 
ment of insects the ovipositor underwent meta- 
morphosis before bees and their specialism ‘came into 
being as such, and that it persisted in this form. 
I should be glad, indeed, if those versed in this 
branch of knowledge would “cast out the devil” of 
my perplexity. Percy E. SPIELMANN. 
21 Cadogan Gardens, London, S.W., May 14. 
Glouds and Shadows. 
Tue shadows to which Mr. Cyril Crossland refers 
in his letter to Nature of May 30 have. straight, 
fairly well-defined edges, and are therefore certainly 
cast by the sun itself, which would be still visible 
to anyone in the high reflecting layer, whether to 
east or west of the observer. They are certainly not 
cast by light ‘‘reflected from the glowing clouds in 
the west,” as Mr. Crossland thinks. The con- 
vergence of these rays towards the east, which the 
present writer has often seen, is purely a perspective 
ag te, 
