74 
POPULAE SCIEIJTOE I^EWS. 
[Mat, 1891. 
the northerly exceeded the southerly by thu-ty- 
five. D. W. 
Natick, April 6, 1891. 
[Specially Computed for Popular Science News.] 
ASTRONOMICAL PHENOMENA FOft MAY, 
1891. 
There will be a total eclipse of the moon on 
Miiy 23, but it will not be visible in this country, 
as the middle of the eclipse occurs at about 1.30 
P. M., eastern time. It will be visible in the east- 
ern hemisphere. Mercury will be an evening star 
at the beginning of the month, but rapidly ap- 
proaches inferior conjunction with the sun, pass- 
ing between the earth and sun on May 9 — giving 
us a transit. It then becomes a morning star, and 
moves rapidly toward western elongation. By 
the end of the month it is over 20° distant from 
the sun, but it is at the same time very far to the 
soutli, so that it will not be easily visible. The 
transit occurs on May 9th, and only its beginning 
can be seen in the eastern part of the United 
States, the first contact coming just before sunset 
and the other phases occurring after sunset. 
Transits of Mercury occur on or near May 9 or 
November 7, when the sun is near one of the 
nodes of Mercury's orbit, and there are usually 
six in a period of forty-six years — two May tran- 
sits and lour November transits. The next will 
come on November 10, 1894. They are of no great 
astronomical importance. Venus is still a morn- 
ing star, and rises about two hours before the sun. 
It will be considerably less bright thau it was 
during the winter. Mars is slowly approaching 
conjunction with the sun. It is still an evening 
star, and sets about two hours after the sun at the 
beginning of the month and somewhat earlier at 
the end. It has fallen off so much in brightness 
as to be no longer a conspicuous object. It will 
be occulted by the moon ou the evening of May 9, 
but the occultation will not be visible in the 
United States, except, possibly, in the extreme 
southwest. Jupiter is getting into better position 
for observation. It is still a morning star, but by 
the end of the month rises about midnight. It is 
moving eastward in the constellation Aquarius, 
and on the morning of May 29 passes very close 
to the fourth magnitude star Phi Aquarii. Saturn 
is on the meridian shortly after 8 P. M. on May 1, 
and shortly after 6 P. M. on May 31. It is in the 
constellation Leo, and is nearly stationary among 
the stars. It is in quadrature with the sun on the 
morning of June 1. Uranus is in the constellation 
Virgo, and is on the meridian at about 11 P. M. 
on May 1, and at about 9 P. M. on May 31. No 
very bright star is near it. y 
The Constellations.— The positions given are for 
latitudes differing not many degrees from 40° 
north, and for 10 P. M. on May 1, 9 P. M. on May 
16, and 8 P. M. on May 31. Canes Venatici is in 
the zenith. To the south, on the meridian, are 
Coma Berenices, Virgo, and Corvus. A few of the 
most northerly stars of Centaurus are on the 
south horizon. In the southeast is Libra, and 
below it, just rising, is Scorpius. Bootes is high 
up, east of the zenith, and below it are Hercules 
and Ophiuchus. Lyra and Cygnus are low down 
in the northeast. The principal stars of Draco 
are above, at about the same altitude as the pole 
star. Cassiopeia is on the north horizon. Per- 
seus aud Auriga are setting in thfe northwest. 
Ursa Major is high up, near the zenith, most of 
the stars being west of the meridian. Gemini is 
near the western horizon. Cancer and Leo fol- 
low, above, to the left. Canis Minor is below 
Cancer, near the soutliwest horizon. M. 
Lake Forest. Ili,.. April 5. 1891. 
QUESTIONS AND ANSWERS. 
Letters of inquiry should enclose a two-cent 
stamp, as well as the name and address of the 
writer, which will not be published. 
Questions regarding the treatment of diseases 
cannot be answered in this column. 
A. R. L., Penn. — I have a batteiy of several 
cells, biit upon connecting them together the gal- 
vanometer shows no stronger current than it does 
when one only is used. What is the matter? 
Answer. — The trouble probably lies in the way 
you have connected the cells together. To obtain 
the greatest electromotive force, you must connect 
the zinc of one cell with the carbon of the next, 
and not connect all the zincs and all the carbons 
together. 
I. L. M., 1^. T. — Is it not possible that there is a 
stratum of hydrogen or other light gases, expelled 
from volcanoes or gas wells, resting on the top of 
the earth's atmosphere? 
Answer. — The law of diffusion of gases would 
forbid this being the case. When a light and a 
heavy gas are brouglit into contact, even if the 
lighter gas is placed uppermost, the two gases 
will, in a short time, become uniformly mixed, 
without regard to their different specific gravities. 
If this were not the case, all the carbonic dioxide 
in the air would settle to the surface of the earthr; 
forming a layer several feet in thicliness, and ani- 
mal life would cease to exist, except on the sum- 
mits of hills and mountains. 
E. G. K., New Jersey. — How is vanilline, or arti- 
ficial vanilla flavor, procured from pine trees ? 
Ansioer. — A substance known as coniferin is 
found in the gummy liquid which is formed in 
the spring between the inner and outer barks of 
coniferous trees. By oxidizing with sulphuric acid 
and bichromate of potash, coniferin is changed 
into vanillin, identical with that occurring in the 
vanilla bean. It is at present also largely prepared 
from eugenol, a substance occurring in oil of 
cloves. Although artificial vanillin is quite ex- 
tensively manufactured, it is much inferior to the 
natural product. 
R. M. D., Mass. — The "Japanese filter paper" 
mentioned in a recent Issue is the same as that of 
which the common paper napkins are made, They 
can be obtained of any stationer at a very small 
cost. 
J. D., Mass. — How is the paper prepared which 
is used in the toy barometers, so called, and 
which changes color according to the state of the 
weather? 
Answer. — The paper is soaked with a strong so- 
lution of muriate of cobalt (cobaltous chloride), 
and allowed to dry. In damp weather it is of a 
pink color, which changes to blue in dry weather 
or when the paper is warmed. Although an in- 
teresting scientific toy, these "barometers" are 
utterly worthless in foretelling changes in the 
weather. 
N. D. B., Boston. — What is "fuming sulphuric 
acid," and how does it differ from the ordinary 
kind? 
Answer. — Fuming sulphuric acid is a mixture 
of two parts of ordinary sulphuric acid (H, SO^) 
with one part of sulphuric anhydride (SO3). It 
was first made by Basil Valentiue over four centu- 
ries ago, and was for a loug time the only "oil of 
vitriol" known. The fuming in the air is due to 
the escape of vapor of sulphuric anhydiide. It is 
prepared by the distillation of ferrous sulphate 
(Fe SO4), and is now made in considerable quan- 
tity at Nordhausen in Saxony. Its principal com- 
mercial use is as a solvent of indigo for use in dye 
works. 
W. G. IL, Penn. — How are the "magic papers" 
made which, when touched witli tlie end of a 
glowing match, form words or designs by the 
jjassage of a burning spark through the paper? 
Answer. — They are made by tracing tlie desired 
words or figures on absorbent paper with a strong 
solution of nitrate of potash (saltpetre). When 
touched with a piece of glowing charcoal, the 
paper will ignite and smoulder without bursting 
into flame, and the oxygen in the saltpetre will 
support the combustion, which will follow the 
lines traced by the solution, but will not extend 
to other parts of the paper. 
LITERARY NOTES. 
Petrology : An Introduction to the Study of the Ig- 
neous BocJcs, by Frederick H. Hatch, F. G; S. 
New York: Macmillan & Co. Price, 90 cents. 
The study of rocks, which are simply collections 
or mixtures of different mineral species, is an in- 
teresting and important one, and deserves moi-i> 
attention than is usually given to it in elementary 
science teaching. A book that should briefly de- 
scribe the mineral constituents and internal struct- 
ures of the igneous rocks, their mode of occurrence 
at the surface, and their origin beneath the cru?1 
of the earth, has long been a desideratum among 
English text-books of science. With the view of 
filling this giip this little book has been prepared ; 
and we can recommend it, not only as a useful 
introduction to the subject, but also as a handy 
work of reference. 
Appleton's School Physics; price, .$1.20. Advance'} 
Lessons in English Grammar; price, 60 cents. 
The above are among the latest publications of 
the American Book Company, of New York, and, 
like all the other text-books published by this 
company, are distinguished by their accuracy, re- 
liability, and completeness. In the study of phys- 
ics, especially, a work comprising the results of the 
most recent investigations is very welcome ; and 
a glance over the pages of the advanced grammar 
shows how many commendable changes have been 
made in the teaching of this rather dry subject, 
within the past few years. 
Simple Lessons in Astronomy, by Dr. Lewis 
Swift, of the Warner Observatory, Rochester, N. 
Y., is a collection of fifty-two popular articles in 
astronomy, reprinted from the columns of the 
Bochester tfnion and Advertiser, in which they were 
originally published. We can most he.artily re- 
commend them to the perusal of all our readers, 
especially as they present the profovmd knowledge 
of one of our most eminent astronomers in sucli 
a clear and interesting manner. 
P. Blakiston, Son & Co., the medical publishers 
of Philadelphia, announce for early publication, 
A Handbook of Local Therapeutics, hemg a practi- 
cal description of all those agents used in tlie lo- 
cal treatment of disease, such as ointments, plas- 
ters, powders, lotions, inhalations, suppositories, 
bougies, tampons, etc., and the proper methods of 
preparing and applying tliem. This book will 
have several new features that demand considera- 
tion, namely, its combined authorship that guar- 
antees thorough work, its incorporation of mate- 
rial hitherto inaccessable, and its general practical 
character that oft'ers directly to the practicinj;- 
physician many important details in the treatment 
of diseases that the usu.al text-books omit. 
The Cassell Publishing Co. have issued another 
novel in the "Unknown Library" series. The- 
story of Eleanor Lambert. Price, 50 cents, clotli. 
Estes & Lauriat, Boston. 
Pamphlets, etc., received : The Belation of Life 
Insurance to Inebriety, by T. D. Crothers, M. 1)., 
Hartford, Conn; Besection of the Optic Nerve, l>y 
L. Webster Fox, M. D., Philadelphia; Copyright 
Laws of the United States, (including z\ct of 1891), 
by tlie F. H. Gilson Co., Boston; Education at the 
Michigan Agricultural College, by President (). 
Chute; Camera Notes for Ornithologists, by R. \\. 
Shufeldt, M. D., Washington ; and the Proceedings 
of the Thirteenth Convention of the Empire State 
Association of Deaf Mutes. 
To Locate the Deficient Working of Ma- 
chinery with numerous points of friction, causes 
often both annoyance and waste of time, owinn 
to the surrounding noise interfering with the ol'- 
servation of the sound to be isolated. The Beviir 
Industrielle mentions as an effective .and exeeeil- 
ingly simple means of overcoming this difficulty 
the use of a rubber tube about a yard long, one 
end of which is placed in the ear and the other 
passes over the suspected spots. The vibrations 
from all other parts th.an the one covered beiiii;- 
excluded, it is an easy matter to locate a jariing 
noise, and, when found, to observe the intensify 
and periodicity with which it occurs. 
