496 
gradual hauling-around to west-north-west again in 
the succeeding twenty-four hours. The arrows are 
here drawn proportional to the velocities (maximum, 
9.9 miles an hour; minimum, 5.6), as they should 
better have been in the original. The veering in the 
other months is much less regular. The little pam- 
phlet affords excellent material for use in teaching, 
as well as for use in improving weather-predictions. 
No. xi., by Lieut. F. K. Ward, of the same series 
of notes, treats of the elements of the heliograph, 
for use in military signalling, with the advantage 
of silently calling the attention of those to whom 
the signals are addressed without being visible 
to the enemy. No. xii., the latest of the series, by 
Sergeant J. K. Finley, is on the special character- 
istics of tornadoes, giving a concise description of 
their peculiarities. _We should have been glad to see 
in it a statement of what the signal-service is attempt- 
ing, in the way of tornado studies, by means of its 
special reporters. 
—R. Baron, writing to Nature from Antanana- 
rivo, Madagascar, of a curious habit of insects, says, 
‘One morning, while sitting by the side of one of 
these streams, I noticed a papilio, which is an insect 
measuring about four inches from tip to tip of its 
wings, resting ona wet bank; and, wishing to procure 
it as a specimen, I approached it as gently as possible, 
the creature being apparently so absorbed in what it 
was about as to be totally unconscious of my prox- 
imity to it. Noticing strange and unaccountable 
movements, —sundry jerks and probings with its 
proboscis, —I quietly sat down near it to watch it 
more closely. I observed that every second or two a 
drop of pure liquid was squirted (not exuded merely) 
from the tip of its abdomen. I picked up a leaf that 
was lying near, and inserted the edge of it between 
the insect’s body and the ground, so as to catch the 
liquid. Unfortunately, I had no watch with me at 
the time, nor means of measuring liquids; but I 
reckoned that about thirty drops were emitted per 
minute. I held the leaf for about five minutes, — as 
nearly so as I could reckon, — and at the end of that 
time there was caught in it about a saltspoonful of 
what seemed to be pure water, without either taste 
or color. After watching the butterfly for a time, I 
seized it by the wings between my thumb and fingers 
with the greatest ease, so utterly lost did it appear to 
be to what was going on nearit. In another spot I 
saw as many as sixteen of these large butterflies 
within the space of a square foot, all engaged in the 
same strange action.”’ 
— According to the London Academy, an ancient 
human skull has been found at Podhaba, near Prague. 
It was unearthed in a bed of chalk where the tusk of 
a mammoth had been dug out a few days previously, 
which gives an indication of its age. The character- 
istics of this skull are the extremely low forehead 
and the excessive development of the ridges, in both 
of which points it resembles the famous Neanderthal 
skull, though its facial angle is yet lower. 
— The Entomological society of Washington has 
organized with the following officers: president, Dr. 
C. V. Riley; first vice-president, Dr. J. G. Morris; 
SCIENCE. 
i, 
(Vou. III, No. 63. 
second vice-president, George Marx; recording sec- 
retary, E. A. Schwarz; corresponding secretary, L. 
O. Howard; treasurer, Benjamin P. Mann; execu- 
tive committee, the officers and Dr. W. S. Barnard, 
P. R. Uhler, and Dr. A. J.Shafhirt. The first regular 
monthly meeting of the society was held April 3, in 
the council-chamber of the U.S. national museum. 
The active membership list of the society numbers 
over twenty names. Regular meetings are held on 
the first Thursday evening of each month. 
— The pilot chart of the hydrographic office for 
April embodies several neat improvements on the 
preceding numbers. The printed supplement is 
replaced by a greater detail of conventional figures, 
with dates, printed in red on the chart; so that there 
is no longer necessity of looking elsewhere for needed 
information. The rig and attitude of wrecks are 
graphically represented, the name and date of obser- 
vation being placed beside them. Wrecks observed 
more than once are plotted in all their positions with 
dates, and connected by a dotted line. Thus, from 
Jan. 7 to March 12, the schooner Maggie M. Rivers 
had drifted from off Cape Hatteras about five hundred 
miles east-south-east, obliquely across the ordinary 
course of the Gulf Stream. An intermediate posi- 
tion was noted on Feb. 6. One water-spout is recorded 
for March 3, two hundred miles east of Norfolk. It 
would be worth while to give the hour of such tran- 
sient phenomena. Bergs and field-ice were very plen- 
tiful south-east of Newfoundland. Hereafter the 
charts will be sent to press the first of every month. 
The news of the previous month will be given as far 
as received, and any thing coming in later will ap- 
pear on the next issue. 
—It is rather late, but perhaps not quite too late, 
to call attention to the exceedingly important article 
by S. P. Langley, on the determination of wave- 
lengths in the invisible prismatic spectrum, in the 
March number of the American journal of science, 
simultaneously published, also, in the Philosophical 
magazine and some of the continental journals. 
It gives the first, and so far the only, reasonably 
accurate wave-length determinations in the lower in- 
visible portion of the spectrum. The results were 
obtained by a very ingenious and unexceptionable 
combination of grating and prism, and their correct- 
ness is beyond dispute within the limits of accuracy 
assigned. They show conclusively that the corre- 
sponding wave-lengths published by previous (and — 
some contemporaneous) investigators are, at best, — 
only roughly approximate, because founded on extra- 
polation from formulae which break down in the 
region of longer wave-lengths. The formulae of Red- 
tenbacher, Cauchy, and Briot, were all investigated, 
and all fail; Briot’s turning out the least inaccurate. 
Professor Langley’s work makes it evident that the 
theory of dispersion needs revision and perhaps 
reconstruction. 
Some of the results given in this article have been 
published before, within a year or two, in a fragmen- 
tary way, in the Comptes rendus, and in papers read 
before the National academy and elsewhere ; but we 
