106 
POPULAE SCIEIvTCE l^WW^. 
[J0LY, 1891. 
twenty-tliree Mays has been 2.92 inches, with ex- 
tremes of .55 inch iu 1878, and 4.8,S iuclies in 1890. 
In 1879 and 1887, also, tliere was less tlian one 
inch iu May, but iu tiiose years, lilie the present, 
large amounts liad fallen in April and preceding 
moutlis. Tlie amount this year since January 1 
was 29. .35 inches, while the average for these five 
mouths in twenty-three years has been only 22.33. 
The amount of precipitation the present spring 
was 14.21 inches, while the average for the last 
twenty-three springs has been 12.50 inches, with 
extremes of 8.44 m 1880, and 17.39 in 1890. 
PRESSURE. 
The average pressure the past month was 29.996 
inches, with extremes of 29.70 on the 1st, and 
30.40 on the 20th and 21st,— a rauge of .70 inch. 
The mean for the last eighteen Mays has been 
29.942 inches, with extremes of 29.868 in 1874, and 
30.038 iu 1887,— a range of .170 inch. The sum of 
the daily variations was 3.94 inches, giving a 
mean daily movement of .127 inch. This average 
the last eighteen Mays has been .123, with ex- 
tremes of .073 and .170. The largest daily move- 
ments were .38 and .37, while 14 observations were 
stationary — indicating much steady weather. 
The average pressure the last spring was 29.997 
inches, with extremes of 29.12 and 30.45, both in 
April. The daily variations were .174 inch. 
VFINDS. 
Tlie average direction of the wind the past 
month was W. 11° 53' S., or one full point south 
of west. Tlie mean for the last twenty-two Mays 
has been W. 1° 33' N., with extremes of E. 63° 
45' X. in 1881, and VV. 57° 32' S. in 1887,— a range 
of 173° 47', nearly half the entire circle. The rel- 
ative progressive distance travelled the last month 
was 38.83 units, and during the last twenty-two 
Mays 552.2, an average of 25.24, — showing much 
less easterly winds than usual the last month. 
The mean direction of the wind this present 
spring was W. 26° 2' X., while the average of the 
last twenty-two springs has been W. 29° 10' X. 
The distance travelled the last spring was 97.93 
units, and the last twenty-two springs 2,138 such 
units, an average of 97.18, — showing the winds 
this spring to have been a very near average. 
D. W. 
NatiCk, June 5, 1891. 
[Specially Computed lor Populak Science News.] 
ASTROXOnCAL PHEXOMEXA FOR JULY, 
1891. 
The earth is in aphelion — that is, it reaches its 
greatest distance from the sun — on July 3, at 10 
P. M. Mercury, at the beginning of the month, 
is a morning star; it passes superior conjunction 
with the sun and becomes an evening star on the 
morning of July 7, and by the end of the month 
is well out toward eastern elongation, which it 
reaches about the middle of August. It is rather 
too far south of the sun to be easily seen. Venus 
is still a morning star, but it is getting nearer the 
sun, and by the end of the month rises only about 
an hour earlier. It is much fainter than it was in 
the spring, and is moving toward superior con- 
junction, but will not reach it until the middle of 
September. Mars is quite close to the sun through- 
out the month, too close to be seen, and passes 
conjunction, changing from an evening to a morn- 
ing star, on the morning of July 30. Jupiter is in 
the constellation Pisces, and moves slowly east- 
ward among the stars until July 8, when it stops 
and begins to move westward, but the whole mo- 
tion is only about equal to the moon's diameter. 
It rises at the beginning of the month at 11 P. M., 
and about two hours earlier at the end. The fol- 
lowing eclipses of Jupiter's satellites may be seen 
from some point or other in the United States. 
All the phenomena take place on the left of the 
planet, as seen in an inverting telescope. D. de- 
notes disappearance; R., reappearance. Times 
are Eastern Standard. 
1. D. July 
I. D. July 
IV. R. July 
I. D. July 
II. D. July 
I. D. July 
III. R. July 
II. D. .Tuly 
I. D. July 
III. D. July 
III. R. July 
II. D. July 
I. D. Jiily 
I. D. July 
4, 3h. 49m. A. M. 
5, lOh. 17m. P. M. 
7, 12h. 4m. A. M. 
8, 5h. 4.3m. Jt. M. 
11, llh. .39m. P. M. 
13, 12h. 12m. A. M. 
19, 12h. 14m. A. M. 
19, 2h. 14m. A. M. 
20, 2h. 6m. A. M. 
26, 12h. 55m. A. M. 
26, 4h. 15m. A. M. 
26, 4h. 48m. A. M. 
27, 4h. Om. A.M. 
28, lOh. 29m. P. M. 
Saturn is in the constellation Leo, and during 
the month moves eastward among the stars about 
2%°. It sets at about 11 P. M. on July 1, and at 
about 9 P. M. on July 31. During the month it is 
quite a conspicuous object in the sou'.hwestern 
sky in the evening. Uranus is in the constellation 
Virgo, and is in the southwestern sky, following 
Saturn a little less than three hours. Xeptune is 
a morning star in the constellation Taurus. 
The Constellations. — The positions given hold 
good for latitudes differing not many degrees 
from 40° north, and for 10 P. M. on July 1, 9 P. M. 
on July 16, and 8 P. M. on July 31. On the south- 
ern meridian are Corona Borealis, near the zenith, 
and Scorpius, down near the horizon. Sagittarius 
is just rising in the southeast. Hercules is east 
of the zenith. Aquila is about half-way up, a 
little south of east. Lyra is a little north of east, 
somewhat higher than Aquila, and Oygnus is be- 
low Lyra. Delphinus is near the eastern horizon. 
Draco lies on both sides of the meridian, between 
the zenith and pole. Cepheus is to the right of 
the pole star; Cassiopeia near the horizon, a little 
east of the meridian. The principal stars of Ursa 
Minor lie near the meridian, above the pole. Ursa 
Major is to the left, with the pointers at about the 
same altitude as the pole star. Bootes is just west 
of the zenith, and Leo is near the western liorizon. 
Virgo follows Leo, low down in the southwest, 
and Libra lies between Virgo and Scorpius. 
M. 
Lake Forest, III., June 3, 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. 
QtJESTiONS regarding the treatment of diseases 
cannot be answered in this column. 
T. D. X., Milwaukee. — What is the greatest dis- 
tance to which the most powerful modern cannon 
can throw a shot ? 
Answer. — From nine to twelve miles, according 
to various conditions of powder, w ind, etc. 
Subscriber, Vermont.—The laws governing the 
action of lightning are not well understood, owing 
to the impossibility of studying it in the labora- 
tory, and the uncertain and uncontrollable nature 
of the natural discharges. Although currents of 
such intensity would probably not act in exactly 
the same way as those produced by batteries or 
dynamo machines, yet the same general principles 
would undoubtedly apply to all manifestations of 
electric energy. It is a well-established fact that 
lightning-rods, properly applied, and with a good 
ground connection, do furnish a large measure of 
protection; and, although we have. obtained little 
additional knowledge regarding them since Frank- 
lin's day, there is no reason why we may not in 
the future arrive at a much better understanding 
of the nature and laws of lightning, and be able 
to protect buildings from its destructive effects 
with absolute certainty. 
LITERARY X0TE8. 
An Elementary Handbook of Potable Water, by 
Floyd Davis. Ph. D., Silver Burdett & Co., 6 
Hancock Avenue, Boston. 
This book is from the pen of an able chemist 
and sanitarian, who writes from the standpoint of 
an experience gained from the examination and 
study of nearly one thousand water supplies. 
The discussions are clear, compact, vivid, and sat- 
isfying. They cover well the field of inquiry, 
and display a thorough knowledge of the subject 
in hand. The impurities in drinking-water that 
are oftenest the cause of disease and death are dis- 
cussed and the natural and artificial processes of 
removing them from water are also given due con- 
sideration. But all methods of analysis are 
avoided, except some of the elementary qualita- 
tive tests given in the appendix. 
Table for the Determination of Minerals by Physi- 
cal Properties, by Persifor Frazer. J. B. I^ip- 
pincott & Co., Philadelphia. Price, $2.00. 
These tables are very full and complete, and are 
formed upon a system which enables one to de- 
termine in a very short time and with a few 
simple instruments which may be carried into the 
field, the identity of any unknown and doubtful 
mineral. It will be found extremely valuable to 
students, both as an aid for study at home and as 
a companion upon collecting tours. The present 
third edition has been entirely rewritten and 
brought down to date. 
Science of Every Day Life, and Science Applied to 
Work, by John A. Bower, F. C. S. Cassell & 
Co., New York. 
These two elementary works are intended for be- 
ginners in scientific study without previous knowl- 
edge of the subjects treated of. They are most ex- 
cellent in their way, and we can recommend their 
perusal to all desiring to obtain a knowledge of 
the first principles of physics and mechanics. 
'I'he endeavor has been made to give correct scien- 
tific information in plain language, so as to form 
a basis for successful work in the interesting and 
important branches of stady here dealt with. 
We have before made mention of The Fairyland 
of Flowers, (Educational Publishing Company, Bos- 
ton), but a more careful examination of this ele- 
mentary text-book of botany for children and 
others commencing the study of this fascinating 
branch of science, compels us to give it an addi- 
tional word of commendation. 
The Friend of Death is the fantastic title of the 
latest number of the " Unknown Library," pub- 
lished by the Cassell Publishing Co. of New 
York, (50 cents) , but it is a powerfully written 
story, showing considerable literary ability, and 
will be enjoyed by novel readers. 
The Pantobiblion. is a new monthly periodical, 
published at St. Petersburg, Russia, by A. 
Kersha, which is intended to be a complete sum- 
mary of contemporary scientific literature, both 
books and periodicals. It will also contain criti- 
cal articles on scientific publications and a review 
of the current periodical literature of the world, 
showing the contents of all the chief scientific 
magazines of the day devoted to the applied sci- 
ences and published in all the princip.al languages. 
The subscription price is '24 shillings, (about 
$6.00) per year, and Messrs. I). Appleton & Co., 
of Xew York, are the American agents and will 
receive subscriptions. 
Pamphlets, etc., received : Protection or Free 
Trade i^ by Henry George; Report of the Smithso- 
nian Institution for 1SS9 ; On Chemism, or The 
Organization of Matter, by A. E. Dolbear; The 
Limits of Scientific Inquiry, by Dr. H. Hensoldt; 
Osteological Notes on the North American Kites, 
Mortuary Customs of the Navajo Indians, Fossil 
Birds from the Equus Beds of Oregon, and Notes on the 
Classification of Pigeons, all by \i. W. Shufeldt, M. 
D. ; and the Report of the Numismatic and Antiqua- 
rian Society of Philadelphia. 
