Vol. XXV. No. 12.] 
POPULAR SCIENCE NEWS. 
187 
in. 
D. 
December 
IV. 
R. 
December 
II. 
R. 
December 
I. 
R. 
December 
I. 
R. 
December 
II. 
R. 
December 
I. 
R. 
December 
II. 
R. 
December 
I. 
R. 
December 
III. 
R. 
December 
I. 
R. 
December 
II. 
R. 
December 
I. 
R. 
December 
III. 
D. 
December 
III. 
R. 
December 
I. 
R. 
December 
nent object in the western sky in the evening. 
On December 1 it sets a little before midnight, 
and two hours earlier at the end of the month. 
The following eclipses of his satellites may be 
seen from some part or other of the United 
States. The phenomena take place off the right- 
hand limb of the planet. D. denotes disappear- 
ance ; R., reappearance. Times are Eastern Stand- 
ard. 
2, Ih. 29m. A. M. 
4, 7h. 32m. P. M. 
4, 7h. 37m. P. M. 
7, 12h. IGm. A.M. 
8, 6h. 45m. P. M. 
11, lOh. 10m. P, M. 
15, 8h. 41m. P. M. 
19, 12h. 54m. A. M. 
22, lOh. 36m. P. M. 
23, 4h. 38m. P. M. 
24, 5h. 5ra. P. M. 
29, 4h. 51m. P. M. 
30, 12h. 32m. A. M. 
30, 5h. 40m. P. M. 
30, 8h. 40m. P. M. 
31, 7h. Om. P. M. 
Saturn rises at 1 A. M. at the beginning of the 
month, and at a little after 11 P. M. at the end of 
the mouth. It is in quadrature with the sun on 
December 21. It is moving slowly eastward 
among the stars in the constellation Leo. The 
opening in the rings is gradually growing broader. 
Uranus is a morning star in the constellation 
Virgo. At 5 A. M. December 15 Mars passes it 
about half a degree to the north. Xeptnne is in 
the constellation Taurus, not far from the Pleia- 
des. 
The Constellations. — The positions given hold 
good for latitudes differing not many degrees 
from 40° north, and for 10, 9, and 8 P. M. for the 
beginning, middle, and end of the month, respect- 
ively. The head of Perseus is nearly in the ze- 
nith, the rest of the constellation being mainly to 
the east. Aries is high up on the meridian, south 
of the zenith, and Cetus is lower down. Taurus 
is to the left of Aries, high up on the southeast. 
Below Taurus is Orion, and before Orion is Canis 
Major, just rising in the southeast. Canis Minor 
has just risen in the east. Below Perseus (in the 
zenith) are first Auriga, then Gemini, then Can- 
cer; the last just above the horizon, a little north 
of east. Leo is just rising. Ursa Minor is mainly 
below the pole star. Draco is partly below and 
partly to the left. Cassiopeia has just passed the 
meridian between the zenith and the pole, and 
Cepheus is below Cassiopeia. Cygnus and Lyra 
are low down in the northwest. Andromeda is 
high up, just west of the zenith, and Pegasus is 
below it. Aquarius is just setting in the south- 
west, and Pisces lies between it and Aries. 
M. 
Lake Forest, III., Nov. 3, 1891. 
WEIGHT OF THE CARAT. 
Editor of Popular Science News : 
Deak Sir : I notice on page 159 of your No- 
vember issue that you state that " three and two- 
tenths grains make one carat ; 150 carats in one 
ounce of Troy weight; 1,800 carats in one Troy 
pound of 5,760 grains." This is not correct. A 
carat is equal to about three and one-sixth Troy 
grains (3.168168-f ), and 151% English carats are 
equal to a Troy ounce. In 1877 the weight of the 
carat was fixed by an international syndicate of 
London, Paris, and Amsterdam jewelers at 205 
milligrammes, or 151.76 carats to the Troy ounce. 
The French crown jewels were sold by this carat. 
Very truly yours, 
George F. Kunz. 
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. 
M. H. P., Mass. — What is the cause of the mo- 
tion of the toy known as " Ouija," or the talking 
board, which spells out words and sentences when 
two persons place their hands upon it? 
Answer. — "Ouija"' is nothing but a new variety 
of the once fashionable " Planchette,'' and its 
movements are doubtless due to the same cause, 
which is probably unconscious muscular action on 
the past o4.those touching it. Like many other 
similar psychical phenomena, there is much about 
it that is hard to explain with our present knowl- 
edge, and the action of natural laws as yet un- 
known to us may be involved. It is quite certain 
that neither electricity nor magnetism has any- 
thing to do with the mysterious movements. 
J. M., Penn. — What chemical reaction takes 
place during the effervescence of Seidlitz pow- 
der? 
Ansicer.—'n\e effervescence is due to the escape 
of carbonic acid gas (CO,). When the powders 
are dissolved together the tartaric acid decom- 
poses the bicarbonate of soda, forming tartrate of 
soda and setting the carbonic acid gas free. (2) 
Harvey is usually credited with the discovery of 
the circulation of the blood, but it seems probable 
that it was understood, at least in an imperfect 
way, previous to his time. Shakespeare, in Julius 
Coe'sar, makes one of his characters say : 
"As dear to me as are the ruddy drops 
That visit my sad heart." 
Apparently the pheuomeno7i of circulation is dis- 
tinctly referred to in these lines. 
J. J. F., New York. — Does ice always have the 
same temperature, or can it be made colder than 
32°? 
Answer. — Ice acts in this respect like any other 
solid body, and can be cooled to any temperatui'e 
below 32° that can be produced. It cannot, of 
course, be heated above 32° without melting into 
water; and in the act of freezing, no matter at 
what temperature, the temperature of the ice first 
formed will not fall below 32° until all the water 
is frozen. 
I. N. D., New York. — What is the lowest tem- 
perature any body can have? 
Atistcer. — On theoretical considerations the ab- 
solute zero, or greatest possible cold, has been set 
at — 460° F. ; but this has never been practically 
attained. The lowest artificial temperature yet 
produced is about — 220°, and the lowest observed 
natural temperature about — 70°. 
W. T. C, Penn. — When Jupiter is reflected in a 
mirror two faint reflections are seen on each side. 
Are these his satellites? and if so, why are they 
visible? 
Answer. — The faint images are simply secondary 
reflections of the planet, due to reflections between 
the front and back surfaces of the glass mirror. 
With a metallic mirror they would not occur. The 
same phenomena can be beautifully observed by 
holding a lighted candle before a mirror at one 
side, so that the reflected image is viewed ob- 
liquely. 
S. L. C, Boston. — Is there any way of bleach- 
ing printers' ink, or removing it from printed 
paper? 
Answer. — The basis of printers' ink is lamp- 
black, or carbon. This is a most indestructible 
body, and cannot be bleached by any process or 
agent which would not also destroy the paper. 
J. D. R.. Montreal. — A galvanic battery is con- 
nected with a small electric motor. Motion and 
force are produced. How can this force be traced 
back to the sun ? 
Answer. — The force, or energy, produced by the 
battery is due to the oxidation of the zinc plate 
by the acid. To obtain this metallic zinc, the ore 
must first be reduced by smelting with coal, which 
removes the oxygen with which the zinc is com- 
bined in the ore. In thus breaking apart the 
molecules of zinc and oxygen, energy is absorbed 
from the coal, which is given out again when the 
zinc is oxidized in the battery. As the carbon of 
the coal was obtained [from the decomposition 'of 
carbonic acid gas by the ancient coal plants, 
through the chemical force of the radiant energy 
of the sun, we see that even the force referred to 
must, like all other terrestrial forces, be traced 
back to the central member of the solar system. 
LITERARY NOTES. 
Laboratory Practice, by_Prof. J. P. Cooke, of Har- 
vard University. I). Appleton & Co., New 
York. 
This work comprises a series of experiments on 
the fundamental principles of chemistry, and is 
especially a laboratorj' companion. It is not in- 
tended to be used without a teacher, but is an aid 
both to the teacher in laying out the work of his 
class, and to the student in performing that work. 
It is unnecessary for us to commend this book, as 
the name of its distinguished author is a sufficient 
guarantee of its superiority in every respect; and 
we can only say that in the field of practical 
chemistry it will be found as indispensable as are 
Professor Cooke's "Chemical Philosophy" and 
"New Chemistry" to a clear understanding of 
the theoretical principles of this important sci- 
ence. 
Principles and Practice of Plumbing, by S. Stephens 
ilellyer. Macmillan & Co., New York. Price, 
.81. 2o. 
This is a most valuable treatise upon the plumb- 
er's art in all its branches, including those espe- 
cially important ones of sanitary, water, and 
drainage fixtures. While particularly useful to 
practical plumbers, who will find all the latest 
inventions and molhods of work fully described 
in its pages, it contains much information of gen- 
eral interest. Any person intending to erect a 
dwelling-house will find many extremely valuable 
suggestions in regard to the water supply and 
diainage, upon which the health of the occupants 
will so largely depend. 
The same firm publishes a Pictorial Astronomy 
for General Headers, (§1.25), by George F. Cham- 
bers, F. R. A. S., which is a most excellent pop- 
ular treatise on, this fascinating science, and a 
perusal of whichWill give to anyone a good un- 
derstanding of the tuilrtamental facts and princi- 
ples of the science of the heaveus. Many fine 
illustrations add to the value of the book. 
flow to Make Inventions : A Practical Guide for In- 
ventors, by E<lward P. Thompson, M. E. D. 
■ Van Nostrand Co., New York. 
Every inventor, and everyone interested in in- 
ventions as well, can read this book with pleasure 
and profit, not only for the valuable advice given 
to those occupied in devising new forms of ma- 
chinery and applications of natural forces, but for 
the large amount of incidental scientific informa- 
tion comprised in its pages. 
Messrs. Cassell & Co., of New York, publish 
ITiirty Years of Wit and Humor, by Melville D. 
Landen (Eli Perkins), and all those who love 
good stories are sure to find an abundance of 
them between the covers of the book. All are 
entertaining and most of them are new, very few 
specimens of the "chestnut" family being found 
among them. 
The same firm also publishes in the " Unknown 
Series" three more entertaining novels, — The Ho- 
tel d'Angleterre, Amaryllis, and European Relatives, 
— which are fully equal in interest to the preced- 
ing numbers of the series. 
Pamphlets, etc., received: Dynamics of the 
Sun, by J. Woodbridge Davis; The Comparative 
Osteology of the United States Cohtmbidce, and Ter- 
tian/ Fossils of North American Birds, by R. W. 
Shufeldt, M. D. ; Molecular Motions in the Radi- 
ometer, etc., by D. S.- Troy, (50 cents), of N. D. 
C. Hodges, 47"Lafayette place. New York; Care 
of Eyesight During Infancy and Youth, by L. Web- 
ster Fox, M. D. ; Statistics and Lessons of Fifteen 
Hundred Cases of Errors of Refraction, by George 
M. Gould, M.D. ; A Celestial Messenger, by Gus- 
tavus Ilinrichs, LL. D. ; and 2'he Zodiacal Light, 
by M.rA. Veeder, M.'D. 
