The evening times., 1900-06-30

S7Sitt1rtuS - The summer Sotstice
and the Longest Day of the Year.
In course of the month of July the moon
viii present her phases as follows: First
quarter. on the 4th; full. On the 18th; last
quarter. en- the 18th: new. on the 26th.
Sne viii be in apogee on the Sd and 31st
and in per.gee ca the 18th. The sun.
which On the lst Of the month Will be only
i minutes Of arc below its maximum decii-
nation-that is. the summer solstice-win
traverse in the course of the entire month
an arc Of degrees minutes. At the be-
ginning of the month and at the latitude
Of Washington me sun viii rise and set
so degrees so minutes north Of the true
I east and west points OF the horizon, and
on the last day OF the month very nearly
| p degrees. The expression Of the suns
I rising in the east and setting in the west
is strictly true only on two days of the
year. the beginning OF spring and autumn.
since then the sun is on the equator and
! its diurnal path a great circle, whilst on
any other day its path is a small circle. On
the Ist q the month and at the latitude
Of Washington the sun will end shining
( through windows that directly face the
! north at 20 minutes past a. N, and on
/ the last day about minutes past a. m
The planet Mercury. which on the Sd OF
the month viii reach its greatest eastern
eiougation VIII be in the constellation
Cancer throughout the entire month. We
/ nus VIII be in Gemini and cease to be an
/ evening star bur about the middle OF the
month begin TO act as a morning star
! though since IL rises when the morning
twilight IS far advanced. il viii not be IN
a favorable situation for observation. On
the Sth OF the month Venus will be in in
! feriOr conjunction with the sun. that is
in q straight line between the sun and the
e2~th, and consequently invisible The in
tervai between two conjuncticus Of the
same kind OF planet r. called its synOdIo
period. which in the case Of Venus is 5S4
days. while her sils-eal period-the time
Of complete revolution about the sun
4 is only 225 days.
Consequently Venus viii remain q morn
/ ing star for 292 days and then become an
/ evening star for as many days. Since We
nus becomes 4 morning star on July s.
3 IL viii continue 10 act in that capacity
! until April 25 Of the coming year. Mars
[ is in Taurus and acts as a morning star
/ 1t viii rise about o'clock in the morning.
/ OF all the larger planets Mars has the
]
I OF the numerous peCuliarities OF Mars the
/ fact Of the period OF the inner satellite
/ Phobos being the shortest in the whole
! solar system is one. PhobOs revOIves
| abOuT its primary in the remarkably sho-t
/ time Of seven hours and Jhirty-nine min
/ utes. which is not one-third OF the day OF
I Mars. L is owing 10 this fact that Il rises
/ in the West every night for the inhabit-
ants Of Mars. II there are any, and sets in
/ the East after about Eve and a half hours.
] Jupiter is in SCOrpiO. greatly enhancing
/ by its lustre The intrinsic beauty Of that
/ constellation. At about o'clock in the
! July evenings IL is on the meridian. set
/ ting about 2 o'clock in the beginning OF
/ the month and a few minutes past mid
/ night at the end. Not far from Jupiter.
4 toward the East. TIE fine planet Saturn
! shines in the neighboring constellation OF
] SagittaTius. Il sets about two hours later
! than Jupiter. thus being visible nearly
/ throughout the night
The Zones of the Earth.
The division Of the earth's surface into
/ the different zones IS not an arbitrary ar
rangement. like the division Of the land
! into continents. empires. and States. There
/ is an astronomical reason for the division
/ into zones. The boundary lines Of the tor
/ rid zone-the tropics OF Cancer and Cap
I
| the suns apparent annual molten north
| and south. and the lines tha: separate the
| temperate zones from thefrigi6-the polar
! circies-pa-S through the poles OF the
! eclipGc. When th@ sun Is al the summer
solstice the day S longest IN all places
| north Of the equator. but the length Of she
! longest day depends upon the latitude OF
! the place. On the Arctic and Antarctic il
is exactly twenty-f0ur hours; in fact, Oh
.n.rs +. Il
| the midnight sun due north. While at the
| Arctic circle the maximum length Of the
| day is twenty-four hours. it is a whole
I month only ffty-one minutes north OF il
! and at the pole six months Il is somewhat
] peTplexirg to not a few that while the sun
/ has TO sweep through q large arc OF about
| seventeen degrees from the equator 70
| increase the longest day by one hour il
/ only sweeps through an arc OF less than
! one degree from the polar circles to in
/ crease the longest day by whole month.
The matter. hOweve-, becomes clear BY
/ considering that the ecliptic-the apparent
/ path of the sUn-cuts the parallels Of lati-
1 tude at smaller angles with increasing Iati-
tude so that the sun in its motion north
| and south tends more and more TO par
| ailelism with the equator, and that as a
/ matter Of course its motion in declination
| becomes the slower the nearer It is to
It's northern or southern boundaries the
I solstices. There is nothing more interest
ing than the twofold motion Of the sun
| in right ascension and declinaucn. upon
| the former of which its motion among
/ the consultations of the zodiac and upon
the latter Of which the seasons and the ex-
I tent and limits OF the terrestrial zones de-
pend.
A very interesting question is how far
/ one would have 70 rise above the surface
| of the earth in o-her zones than the frigid
| in order to see the midnight sun. The eIe-
walton in the latitude Of WaShington
whence to see the Sun at midnight at the
/ time Of the sumner solstice would be
/ 495 miles, while az the time OF the yernal
| equinox (spring) it would be 234I miles
4 At a latitude OF degrees and 30
| minutes 2t the time OF the summer soIstice
! the elevation required wodId be equal to
! the earths diameter. ana at the latitude
! thirty degrees at the beginning Of spring
| it would have the same elevation of the
| eaTth's diameter At the tropics the ele-
| vatiOn at the beginning Of summer would
be about the earth's radius.
The Scorpion.
OF all the consultations that are on the
meridian at about O'Clock in the July
| evenings the most striking is Scorpio. OF
| Scorpius, the principal ccnfguration of
whose stars is boys kite with lone
! the first magnitude and in its intense
redness resembles the planet Mars, whence
| its name. which means equal to Ares.