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Psalmist says, ‘‘there is no speech nor language, their voice is not heard ”’ by the 4A STUDIES OF THE STARS ear. Neither is the voice of the flowers, But how can the lover speak more gently, beautifully, or significantly, or how can the loved one hear miore clearly, or feel more deeply? How can God write his name more widely or plainly, hold the open page before all men more constantly, or how can we read the message in more impressive language? Some have asked whether the myriads of distant worlds were inhabited. It is not’ known. Perhaps it is a sufficient cause of their being that they should tes- tify so effectually of .God to every man, whether savage or sage, in all ages of time. Let us learn to read the hieroglyphics, and then often turn to the blazonry of the page. A million torches, lighted by thy hand Wander unwearied through the blue abyss; ‘They own thy power, accomplish thy command, All gay with life, all eloquent with bliss. What shall we call them? Piles of glorious light, A glorious company of golden streams, ‘Lamps of celestial ether burning bright, Suns lighting systems by their joyous beams ? But thou to these art as the noon to night. —DERZHAVIN. THE .,SUN. “ His countenance was as the sun shining in his strength.”’ Diameter of Sun, 852,000 miles. Revolves on its axis in 25 days. Let us cut ourselves loose from the world, from all worlds, and float as dis- embodied spirits at will. Behold! before us the Sun. How vast and seemingly infinite. When one has journeyed for weeks on the ocean, and seen no shore, the Earth has seemed vast. But if the Sun were tunneled through by a hole large enough to receive our world, and we had plenty of such globes to fill up the hole, now many should we use? Roll ina dozen, then 20, then 75 more. It takes 1074 earths side by side to measure the ‘ast diameter of the Sun; 1,252,700 of our earths to make the vast extent of its bulk. Its appearance of ever-during calm is delusive. Its vast atmosphere is traversed by storms. Tornadoes almost cease to mean any thing in such vast commotions. Our little seas and winds sometimes seem to raise tremendous tempests. One can 6 STUDIES OF THE STARS scarcely stand when the wind blows sixty miles an hour. But enlarge the world a million fold, put all its forces into propor- tional activity, and what then? The vast photosphere is often rent asunder in huge chasms, thousands of miles in extent. They close up again. The sides approach each other at the rate of 20,000 miles an hour. The advancing sides strike to- gether. The rising wave of fire leaps thousands of milesinspace. The blazing surge falls again into the incandescent sea, spaces larger than the whole conti nent of America are almost suddenly laid bare of light, and as suddenly over- whelmed. Vast spires of burning hydro- -gen flash out 80,000 miles into space. Professor Young on one occasion saw them projected over 200,000 miles from the surface. It is 300,000 times as hot aS any summer we ever knew. The movement of these spots can be easily illustrated. Take an apple, or any other sphere, pass an axis through it, then in the region of the equator cut various sized irregular spots, and darken them withink. Incline the axis a little to the line of vision and cause your representa- THE SUN. ri tive sun to revolve. Now observe when a spot comes in sight; it appears long, thin, and nearly perpendicular. As it comes to the middle the full breadth appears, but appears thin again as it passes to the farther side. Also, in consequence of the inclination of the axis, the line of the moving spots will curve upward — on one side, and ~ downward on the other. Sometimes as many as fifty spots have been seen at once, and sometimes the sun is wholly clear of them. The period of - the wax and wane of these spots is eleven years, and corresponds with certain mag- netic disturbances and auroral phenomena on the earth. One Sun by day, by night ten thousand shine, And light us deep into the Deity ; How boundless in magnificence and might ! O what a confluence of etherial fires, From urns unnumbered down the steep of heaven Streams to a point, and centers in my sight; Nor tarries there; I feel it in my heart; My heart at once it humbles and exalts, Lays it in dust, and calls it to the skies. —Youne. LIGHT. OUR INSTRUMENT OF INVESTIGA- TION. “God said, Let there be light.” t. Velocity of oh T9r, 000 miles per second, — 2. It carries every-where indications of the material of the bodies from which it springs, and of the media through which it passes. 3. The intensity of illumination of ob- jects at different distances is inversely as the square of the distances. 1. Light goes the distance of the Earth’s circumference in + of a second. If we take.a photograph by exposing the plate ito the light sg44,5 of a second, we have 9 miles of light todo the work. Light goes ‘from the Sun to the Earth in 8 minutes; ‘from the nearest fixed star in 34 years; from the polar star in 45 years ; from more ‘distant stars in thousands of years. They may have been smitten out of existence decarles of centuries ago, but their poured out light is yet flooding the heavens. The wings of the morning bear swiftly to the LIGHT. 9 uttermost parts, but not beyond God’s right hand’s holding and leading. Light is propagated in waves like sound. The air does not move forward, but the undulations send the sound on. Every least ray of light has all the seven colors, each being made by a different number of vibrations. 2. If we examine these colors by means of the spectroscope, we find vast numbers of microscopic parallel lines, some. of which indicate salt, others iron, etc., in the bodies from which light springs, or in the media through which it passes. Suns differing from ours in the elements of their composition reveal it by their light. All these armies of light, from various suns, have a distinguishing uniform, The omniscient Eye seeing a light ray anywhere in the universe, though gone from its source a thousand years, and the very Sun from which it sprung blotted out of exist- ence, is able to tell from which sun it originally came. Our Sun has nearly every substance known on theearth. We have discovered nine elements in Aldeba- ran; only three in Sirius. 3. If a lamp illuminates a page at the to STUDIES OF THE STARS, distance of a foot with a brightness which we call 1,:it will illuminate the same page at a distance of two feet, } as much; four feet, jy as much. Neptune, our farthest planet, receives from the Sun only 94,5 the light and heat on a like extent of surface the Earth receives. And, on the other hand, if two stars appear of equal bright- ness whose distances from us are as I to 4, the more distant star is sixteen times as_ bright as the nearer one. This affords a means of comparing the brightness, and probably the size, of suns whose distances we know. Thus Sirius is equal to 63 of our Suns; the Pole star, 83; Vega, 344; Capella, 430; Arcturus, 516; Alcyone, in the Pleiades, 12,000; a light that is unap- proachable by mortals. Our Sun could not be seen at all at the distance of these bodies. Study the light; attempt the high, seek out The soul’s bright path ; and since the soul is fire Of heat intelligential, turn it aye To the all Fatherly source of Light. —BAILEY. GRAVITATION. 1. Attraction varies in direct proportion to the masses and, 2. Inversely as the square of the dis- tance. There is a force which we call attrac- tion or gravitation. It has certain modes of operation which we know, but of its essence we are profoundly ignorant. It acts with more than human intelligence, and. with inconceivable constancy. It is as if every particle of matter had an attraction for every other particle of mat- ter in the universe. It brings down the apple loosened from the bough, makes the avalanche thunder down the mountain, and holds all worlds together. That two bodies of the same mass, hanging freely in space, being attracted, should meet half way, is one phase of the first law; that two bodies whose mass is as 1 to 81, namely, the Earth and the Moon, being attracted together should meet y4 of the distance from the larger, is another ‘phase. Since every particle of a world pulls its proportionate part, it follows, that if a 12 STUDIES OF THE STARS. body is pulled an amount represented by 150 pounds on the earth, it’ would be pulled twice as much on a body of twice the mass.. Hence an average man would weigh two pounds on the Moon and two tons on the Sun. Who could stand up, or even lie down, under the burden of his own body? But if the Sun attracts ‘so much, why are not all plucked off the Earth, and drawn to its blazing center? Because of the second law. The small Earth near attracts morethan the great Sun far away. Streaming from a point, the influence which would cover a square foot a mile away, would cover four square feet two miles away. Hence the influence of the. Sun on such little bodies as,man_ is not appreciable at such a’ distance, but. is appreciable on such a. vast body as the Moon, or the sea, as will appear when we come to the subject of tides. But why are not the Earth /and all other bodies attracted to a common center in one universal crash and wreck? Because of another force that counterbalances grav- itation, and holds all in delicate,and per- fect equipoise. | GRAVITATION. 1Z Suppose a rifle ball fired from A with force enough to carry it in one second 2,000 feet, to B. Gravity is a force sufficient to cause it to fall in the same second six- teen feet, to. C. The result of both forces. acting at once will cause the ball to take the curved line A, D.. Sothe Earth has a forward motion, A, B, of 68,091 miles an hour. And the sun draws the earth to- ward it, A, C, 247402, miles an hour, giv- ing the line A, D, which, being indefinitely prolonged, circles back to its. starting place, and so the Earth never flies off into: space, nor falls into the Sun. .When the slinger whirls the stone swiftly enough, it will fly off and crash the skull of Goliath ; slowly enough, it will fall on his hand from above. he tension of the string repre- sents attraction, the centripetal (center- seeking) force; the tendency to fly off in a tangent represents the centrifugal (center- fleeing) force. Now in all relations of 14 STUDIES OF THE STARS. whirling worlds, these must pertectly bal- ance each other, and that, not only in re- gard to two bodies, as Moon and Earth, but in regard to the Sun, all its planets, their moons, and myriads of suns besides. Nothing can be more wonderful. The infinite delicacy of the unstable equilib- rium of the universe is inconceivable. The water of our globe is a good illustration. It rests in even poise around all shores. But if it were a trifle heavier or lighter, if the Earth should revolve slower or faster, if the Moon should come nearer or go farther away, if the Sun’s attraction should increase or diminish, these plastic seas would rush, and bury either the poles or the equator miles deep, and leave the de- serted parts miles from any moisture. Job could not understand the balancing of the clouds, much less the balancing of vast systems hung’upon nothing. The Moon is another illustration. In going round the Earth it rushes 480,000 miles nearer the Sun. It feels the Sun’s attrac- tion increase with every mile. It is led thousands of miles out of its true course ; but the elastic hold of the Earth at length prevails, and the Moon climbs away from GRAVITATION 15 the Sun in defiance of its power. The Moon varies its distance from the Earth to the amount of 31,355 miles. The adjust- ment of two bodies and two forces in simple curve would be a comparatively easy matter. But there are over 60 causes of variation from such a simple curve in the case of the Moon. The value of each of these must be considered in calculating an eclipse, or the moon’s place as a guide to the sailor. One planet affects every other. Jupiter’s four moons affect him and themselves. They turned a comet out of its course in 1770, and tangled its path for four months. Still the equipoise is maintained. The scale nods from side to side, but neither pan ever kicks the beam. The universe is infinitely wide, and conquering reason, if self-glorified, Can nowhere move, uncrossed by some new wall Or gulf of mystery, which thou alone, Imaginative faith ! canst overleap In progress toward the fount of Love. — WORDSWORTH, THE: PLANBTS: “He hangeth the earth upon nothing.” Distance from : Hourl Name. Sai! Boe Diameter. “rib ie Yr. Ds. 1 Mercury .. 35,392,000 © 88 3,058 95,000 2 Venus .... 3134,000 © 225 7,510 75,006 Si bartnensere 92,430,000 I. ... 7,926 68,000 4 Mars...... 139,311,000 I 322 4,363 55,000 5 Asteroids , 4 200,000,000 3 230 240 44,000 q 315,000,000 4 225 2,000 41,000 6 Jupiter ... 475,092,000 I1 317 84,843 30,000 7 Saturn. s.% 872,137,000 29 175 70,136 22,000 8 Uranus ... 1,753,869,000 84 ... 33,247 15,000 9 Neptune.. 2,745,998,000 164 ... 37,276 11,000 Looking out from the Earth, we see one body, the Moon, making a circuit about it in 27 days. Looking out from Jupiter, we see four bodies, or moons, making circuits about it at various distances, and in vari- ous times. Looking out from the Sun, we see 8 planets with satellites, making their various circuits about the Sun. The rela- tive size and distances of the Sun and planets may be represented as follows: Put in position a globe 2 feet in diameter— a half of a barrel, or a two bushel basket will do; 14 feet from its center mount on a stick, so as to reach the equator, a mus- tard-seed for the planet Mercury; a pea ditto, for Venus, 3 feet from the Sun’s cen- ter ; another pea, not al] on the same side, THE PLANETS. 17 4 feet away, for Earth; a large pin-head, 6 feet distant, for Mars; 200 specks of pepper on a paper, I1 feet away, for the Asteroids ; a small orange, 20 feet away, for Jupiter; a smaller orange, 37 feet away, for Saturn; a cherry, at 75 feet, for Uranus; and another, at 118 feet, for Neptune. | The speed of Mercury is 79 times as swift as a rifle ball that goes % uf a mile in asecond. The great Earth flies more than. 1,000 miles a minute, besides revolving its. surface 1,000 miles an hour. Yet no bird is. ever unnested or babe waked by the motion. Neptune's motion is less than 200 miles. a minute. The planets do not go round the Sun in. a circle, but in an ellipse, the Sun being in one of the foci. In consequence of this the Earth is 2,066,000 miles nearer the Sun in one part of its orbit than another, and Neptune is 50,384,000 miles neare1. MERCURY. Distance from Sun, 35,392,000 miles. Diameter, 3,080 miles. Looking at the planets separately, little can be said of thts one. He is so near the 18 STUDIES OF THE STARS. Sun little can be seen of him. The aver- age heat of this planet must be about 14 that of boiling water, and for summer temperatures they must need thermome- ters ten feet long. VENUS. ' Distance from Sun, 66,134,000 miles. Diameter, 7,510 miles. This brightest of all stars is never seen more than 47° behind the sun; then it is the Evening Star; or, before it, then it is the Morning Star. Venus has an atmos- \ phere charged with aqueous vapor. She revolves on her axis in 23 hours, 21 min- utes, 19 seconds. Seen from the Earth, it presents phases like the Moon, which will be readily understood by an inspection of figure 2, When Venus is at B she would appear in the refiected light of the Sun as a thin crescent, as seen from A. When she is at C the lower half of its disk would THE PLANETS. 19 be illumined. When at D it would ap- pear round as a full Moon. Her apparent retrograde motion is, also, easily under- stood. The motion of Venus is judged by the distant stars, among which it seems tc be projected. When it is at B it ap- pears among the stars at 1. Passing on to C, it seems to retrograde to 2. Going to D, it passes back to I again. The ret- rograde movements of the exterior planets. are much greater, and as easily under- stood. THE EARTH. Distance from Sun, 91,430,000 miles. Diameter, Polar, 7,898 miles. ae Equatorial, 7,924 miles. Mass, 6,000,000,000,000,000,000,000 tons, More can be shown by illustrations that the reader can produce than by any draw- ing. Put on the table or wall a lamp shade, or other globe, to represent the Sun, mark on it the spots, and incline its axis 74° from the perpendicular. Around this, as one focus, draw several elliptical orbits, at suitable distances, for as many planets as you can represent. Now take an apple or other ball, flattened at the ends; through these pass an axis 20 STUDIES OF THE STARS. sharp enough to stick into any part of the: orbit drawn, and long enough to raise the ball as high as the center of the Sun, Draw the equator midway between the poles, and add meridians of longitude ' and parallels of latitude if you choose. Stick in pins for men, heads up, and sticks for a winter forest ; set up the Earth on its long axis in some part of the orbit, inclined from the perpendicular 234° Many things will now become evident; 4. g., by revolv- ing the Earth on its axis, the morning sun- light will come over the east, then shine from above, and then set in the west. Also the Moon and the dome filled with stars will seem to revolve in like manner. Since men are attracted to the earth, it makes no difference whether their heads are up or down ; indeed, toward the Earth is always down tothem. Hang the Moon from the upper pole so that it will swing Yr THE PLANETS. 21 round the earth near the equator, and it will be seen that when it comes hetween the Earth and the Sun it eclipses that orb, and when it goes behind the Earth into its shadow it is eclipsed itself. Also, when the Moon is nearly between the Earth and Sun it shows only a thin crescent of illu- mination. When it has passed go®°, or $ of a revolution, it would be half illumined ; and when opposite the Sun, and not in the Earth’s shadow, it shows full Moon. Itis seen, also, that the sunlight reaches 234° ' beyond the lower pole, and makes that region perpetual day as the Earth revolves. And 234° about the upper pole is in constant night. Remembering that the Earth’s axis always points to the same north star, z. é., it does not revolve in two directions at once, carry the Earth to the other side of the Sun. Now the upper pole is illuminated, making the days long and | nights short below the 234°, and leaving the lower pole dark. The measurement of the sing is easy. We observe that the North Star is 409 above the horizon at Philadelphia. We go north till it is 41° above, and find we have gone 69 miles, which, multiplied by 3609, 22 STUDIES OF THE STARS gives the circumference, 24,887 miles. The length of the degree differs a little in different places, according to the oblate- ness of the spheroid in those places. The distance of the Sun is measured in several ways: by taking the angles he makes at the two ends of a horizontal line as long as the Earth’s semi-diameter ; by the transit of Venus; by the velocity of light ; and, knowing the Sun’s diameter, measuring his distance by the apparent breadth of the disk. Two lines drawn up from each end of a line 10 inches in length, and perpendicular thereto, will make right angles with that line, be parallel, and, of course, never meet. But if drawn so as to meet anywhere within three hundred miles from that ro inch base line, such is the wonderful per- fectness of astronomical instruments that they would measure how much these an- gles varied from right angles, and know the distance at which they met. Now, to measure the distance of the Sun we could take two stations with the Earth’s diame- ter between them, if necessary. Measurement by the transit of Venus is more exact. The instant when that THE PLANETS. 23 planet touched the edge of the Sun would appear very different to observers on op- posite sides of the Earth, and knowing the distance of Venus from the Earth, the so- lution of the problem becomes easy. We are far from the Sun. Call it in rourd numbers 92,000,000 of miles. If we lay an imaginary track thither, and put on an imaginary locomotive running at the usual express speed, it would take 8 months to reach the orbit of the Moon. Put a little babe on that train bound to: the Sun. He grows up, passes the period of his glad youth, strong manhood, ar- rives at the end of his 70 years, the allotted time of man, but his dying eyes look vainly for a near view of the goal of his life’s journey. Then let another babe take his place. Childhood, youth, manhood, age- another life goes by. Not arrived. Add another life, 70 years more. Not arrived. Add a fourth period of life, then a fifth, and when all five have lived their lives and died, after ‘350 years of travel, that locomotive that has never stopped a min- ute, day nor night, for wood, water, or to cool its glowing axles, would barely get that last man there in time to bury him. 24 STUDIES OF THE STARS, ‘Hardly any thing is quicker than the flash of the sensation of pain. But if a man had an arm long enough to reach the Sun, it would be 135 years before he knew he was burned THE MOON. Mean distance from Earth, 238,818 miles. Diameter, 2,159 miles. Revolution about the Earth, 27 + days. Revolution on axis, same time. The Moon is our next-door neighbor. If you notice a star in proximity to it, you will see that the distance is very percepti- bly different in an hour. On the next ‘evening the Moon will be 13° farther east. This gives an entire revolution from west to east in 27 days. By revolving on its own axis in the same time it manages to show us always the same face. No man ever saw the back side of the Moon. It is a craggy, desolate, upheaved, torn, ‘rent, mountained, chasmed, volcanoed, and moon-quaked orb. The gravity is so small —o'16 that of Earth—that precipices do not tumble down, pits do not fillup. They «can be seen in the southern part 3 miles ‘deep, of all sizes from 4 of a mile to 10 miles across. This little orb, #5 the size THE PLANETS. 25 of Earth, has 28 mountains higher than the “ monarch of mountains,’’ Mount Blanc. Its highest mountain, Doerfel, is 24,945 feet high. The Earth, seen from the Moon, looks ike the Moon seen from the Earth, only 13 times as large. It is sometimes between the Moon and the Sun, and sometimes opposite the sun. But as the Moon al- ways presents the same side to the Earth, Earth seems stationary over that point. The Moon has no water or atmosphere ; if it ever had, they are absorbed in the interior of the burned out char, The path of the Moon around the Earth is indescribable. Mount an 8 inch ball on one end of a 20 foot pole, and a 2 inch ball on the other, and they just rep- resent the Earth and the Moon, and their distance apart; find the center of gravity, mount it on a pivot, and set it whirling. The center of the Earth revolves from this cause alone on an orbit 6,000 miles in diameter, and the Moon in one 476,636 miles in diameter. Carry the whole ap- paratus forward 1,000 miles a minute around the Sun, and the Moon’s path is a set of curves impossible to describe. 26 STUDIES OF THE STARS. ECLIPSES.—If a plane be imagined in which the line of the Earth’s orbit around the Sun lies, that is called the plane of the Earth’s orbit, or the ecliptic. Of course it passes through the centers of the Sun and the Earth. A like plane of the Moon’s or- bit passes the center of the Moon and the Earth. Now, if these corresponded, or were one and the same plane, the Sun would be hidden or eclipsed every time the Moon passed before the Earth, and the Moon eclipsed evéry time it passed be- hind the Earth. But these planes do not correspond. That of the Moon is inclined to the other, passing through it, one half above and one half below. If the Moon should be at a when the Earth was in that part of its orbit, and the intersection of the planes of the orbits in that position, the Sun must be eclipsed. But if the Earth was at d—the intersection.of the THE PLANETS. He | planes remaining the same—and the Moon came between it and the Sun, the Moon would be so far below the connecting line as not to hide the Sun. At some inter- mediate point it might come so near the line of intersection as to partially hide the Sun. Eclipses are greater or less in degree, according to the varying distance of the Earth from the Sun, the Moon from the Earth, and by being in different parts of their orbits. _ TipEs.—The attraction of the Moon for the nearer and farther sides of the Earth varies inversely as the square of the distance. - It attracts the near side much more than the far side. The mobile air and water yield to this attraction more than the more distant mass of solid Earth, and pile up a tide under the Moon. And the solid Earth yields to this attraction more than the far-off air and water of the other side; and hence the Earth, being solid, is pulled away from the mobile air and water of the other side, leaving it piled up on the side of the Earth opposite to the Moon. When the Sun and Moon join their forces in the same line, we have tides one third higher than the Moon’s, 28 STUDIES OF THE STARS, called spring tides. When they exert their forces at right angles with each other the Sun subtracts one third from the Moon’s tides, giving what are called low or neap tides. Bodies of water so small as the great lakes or the Mediterranean Sea are too small to show a perceptible tide. Tides are so much affected by currents, islands, trend of shores, distance of Sun and Moon, etc., as to give great variety of tides; those of the Bay of Fundy being 70 feet, Boston 11 feet, New York 65 leet, etc. The Moon has been getting nearer to the Earth for thousands of years. Will there be a collision between these sailers of the sky? Is a ball large enough to wreck a continent, going at 40 miles a minute, about to meet us going a thou- sand? Never fear. It approaches slowly. It has shortened its time of revolution only 10 seconds in a century; and after approaching the Earth for millions of years, will begin to recede agair by the same power that drew it nigh. What stupendous prophecies human_ science - enables us to make! Shall any prophecy be too difficult for Divine science or Ome niscience to declare? THE PLANETS. 26 MARS. Distance from Sun, 139,000,000 miles:. Diameter, 4,400 miles. Daily revolution, 24 hours 37 minutes; This planet is singularly like the Earth in length of days, variety of seasons, abun- dant vapor for rain, ice around the pole,. which melts as the Sun approaches, and: in divided land and water. We enjoy greatly differing opportunities for acquaintance. Whem we are on op- posite sides of the Sun we are 230,000,000: ‘of miles apart. When on the same side: we may be quite near. If Mars is in that part of his orbit called perihelion, or near- est the Sun, and we at aphelion of our orbit, or farthest from the Sun, we may be only 33,000,000 of miles apart. This: favorable opportunity happens about once: in 79 years. In this year of grace 1877, Mars introduced us to two members of his family we had never seen before. Mr. Hall, of the Washington Observatory, discovered in the month of August twu moons, one having as a period of revo- lution 30 hours 14 minutes, and the other 7 hours 35 minutes. In consequence of this time of revolution being less than, ~ 3° STUDIES OF THE STARS. Mars’ axial revolution, this Moon rises in the west and sets in the east. Probably meither of them is Io miles in diameter. ASTEROIDS. The law of the distance of the several planets from the Sun is expressed by this series :— re) a 6 12 24 48 96 192 Add Pee. Pea Ye dar ee ee eee” 4 4 yp Bee) 16 28 52 100 196 Now this lower line of figures nearly rep- resents the relative distances of the planets. It approximates the truth to say that each one is twice as far from the Sun as the next interior one. Thus it was seen that there was a strange gap be- tween Mars and Jupiter, and twenty-four astronomers made a league to search for the missing planet. Piazzi discovered a small star January 1, 1801, which, despite his long sickness and the loss of the plan- et in the Sun’s rays, was rediscovered by Olbers on December 3, 1801, and named Ceres. This proved to be but the herald of a large body of small planets, of which nearly 200 have now been discovered, having distances from the Sun varying THE PLANETS. 3t from 200 to 315 millions of miles. The combined mass of all these asteroids is not ‘ probably one tenth of that of the Earth. What a proof of the accuracy of astro- nomical observations of movements, when each of these nearly, 200, bodies, which cannot be distinguished from each other. by any appearance they present, can be accurately known, even though not seen for 50 years, by the observation of their line of motion ! JUPITER. Distance from Sun, 475,692,000 miles. Diameter, 85,000 miles. Daily rotation, 9 hours 55 minutes. Behold the monster of planets! All the rest put together would barely equal two fifths of this. It is 300 times the mass of the Earth, and 1,233 times the volume. It is royally attended by four moons. The inner one makes a revolution in 42 hours, (instead of 27 days, as our Moon,) and the outer one in 16 days 16 hours. Eclipses are not only an every-day matter, but al- most hourly. These eclipses have done excellent service in measuring the velocity of light. We know toa second when they take place. But when the Earth is on the 3 32 STUDIES OF THE STARS, opposite side of the Sun from Jupiter these - eclipses take place 16 minutes later than when on the same side as in figure 5. Is celestial chronometry getting de- ranged? No! these great worlds swing, never a second out of time, nor an inch out of place. By: going:to the other side of the Sun we become 184,000,000 of miles farther from Jupiter, and the light that brings us the intelligence consumes the extra time in passing over the extra dis- tance. 184,000,000 miles+960 seconds= 191,000-++miles per second as the velocity of light. A I have seen the rude little telescope with which Galileo discovered these moons. A better one can be bought for five dollars. There is probably no resemblance be- tween the condition of Jupiter and the Earth. The body is probably intensely heated and feebly self-luminous. It has no variety of season. It presents to the THE PLANETS. 33 view of the telescope changing lines of belts and spots from which little can be trustworthily inferred. In consequence of its extreme rapidity of rotation the flat- tening of its poles is very great. The equatorial diameter exceeds the polar by more than 6,000 miles. ‘SATURN. Distance from Sun, 872,137,000 miles. Diameter, polar, 66,500 miles. Diameter, equatorial, 73,500 miles. Axial revolution, 1o hours 30 minutes. This is the most wonderful planet of all. It is the largest, except Jupiter. Its mass is three times the mass of all the other planets combined, Jupiter being omitted. It is 90 times the mass of the Earth, and 700 times the volume. It differs from all other known celestial bodies in having enormous rings. It presents these at dif- ferent inclinations to the Earth. They ap- peared to Galileo, who first saw them, as two small bodies on either side of the planet. Subsequently they presented only . the thin invisible edge to his sight and disappeared altogether. Again they ap- pear as in figure 6. i tly, They lie in the plane of the planet’s equa- 34 STUDIES OF THE STARS. tor, and revolve with it. The outer one is less brilliant, and inside of them both is a dusky semi-transparent ring, seen with difficulty. The inner edge of this ring is constantly approaching the planet, while the breadth of the two outer, or bright rings, is constantly expanding. These | rings are’ supposed to be composed of myriads of independent minute satellites mingled with vapor. Hence not solid. Saturn hasa system of eight moons, some of enormous size and revolving at a great distance. URANUS. Distance from Sun, 1,753,869,000 miles. Diameter, 33,000 miles. The distance of this planet from the ’ Sun is 19 times that of the earth. A train started from the sun thither 6,000 years ago would be only just arriving. , This planet has four moons, which pre- THE PLANETS. 35 sent the wholly anomalous phenomenon of revolving nearly over the poles and ina retrograde direction. NEPTUNE. Nistance from Sun, 2,745,998,000 miles, Diameter, 35,000 miles. The orbit of Uranus had embarrassed astronomers for years with irregularities which could not be accounted for. Bou- vard suggested another exterior planet. Leverrier of France, and Adams of En- ' gland, undertook to tell where it must be from these irregularities. Both succeeded perfectly in determining the mass, orbit, and actual position of an unseen body. On searching in the place indicated, the planet was discovered first at Berlin, and afterward at Cambridge, England. It has one satellite. Probably two. The cold here, unless these outer planets have heat of their own, or an absorptive and reten- tive atmosphere, must be 100° below zero, and the far-off sun looks but little larger than a first class star. We thus reach the outer boundary of the solar system, but have scarcely taken the first steps of a voyage to the surrounding stars. Light 36 STUDIES OF THE STARS. goes to Neptune in four hours, to the nearest fixed star in 34 years. The order of the planets—Mercury, Venus, Earth, Mars, Asteroids, Jupiter, Saturn, Uranus, Neptune—may be re- membered mnemonically thus :—Mercury Vzews Earth; Mars Azd Jupiter che SUN. Or the initials give us a name with French and English titles, as:—M. Ve Maj. Sun. The number of satellites may be remem- bered by this series, beginning with Earth, RY ap te Pl Wi Who rounded in his palm these spacious orbs, And bowled them flaming through the dark pro- found, Numerous as glittering gems of morning dew, Or sparks from populous cities in a blaze, And set the bosom of old night on fire ? — YOUNG. COMETS. “S Wandering stars, to whom is reserved the blackness of darkness forever.’’—JuDE. Notwithstanding our king of day may make Neptune his farthest province, he sends his scouts much farther. When the comet of 1680 wheeled round the Sun, 200 years ago, it commenced an outward march of 4,500 years before it should “ about face”’ and begin its equally longreturn. It seems asifits long ‘“ black- ness of darkness’ were best expressed by the term forever. Some go so far that gravitation turns the other way; other suns allure them, and they go as envoys to other systems of worlds than ours. The orbits of these strange visitors are extremely elliptical, circles whose two sides have been well-nigh brought together. They come rushing down into the steady, well-ordered ranks of planetary bodies from all points of the sky, above, below, around. They are like dashing aids-de- camp among the ordered lines of battle. Their speed is sometimes frightful. The comet of 1680, above referred to, went, when nearest the Sun, 1,000,000 miles an 38 STUDIES OF THE STARS. hour. It went within 130,000 miles of the Sun, and must have been heated 2,000 times hotter than red hot iron; others wheel outside of Neptune’s orbit, and are never light or warm; 700 have been seen by the naked eye since the time of Christ. The number that belongs to our Sun is supposed to be several millions. They may have tails 200 millions of miles long, like the comet of 1843, or no tail at all, like that of 1585; or the same comet may be in both of these conditions at different times. They are not specially dense bodies, for small stars have, at times, been seen through their brightest parts. Biela’s comet was once famous for the regularity of its return, having a period of 6% years. In 1847 it divided into two comets under our eyes. It was seen in 1852, the parts separated by a distance of 1,250,000 miles. It was not seen in 1866 and 1872, but the brilliant shower of meteors in November 27, 1872, was, doubtless, occasioned by some of the remains of that comet. When that shower of streaming light flashed in our upper air, Klinkerfues, a German as- tronomer, telegraphed to Madras, on the THF PLANETS. 39 other side of the globe, “Bela touched earth on 27th. Search near Theta Cen- taurt.”’ And searching there the ob- server saw the departing comet, through some part of which the Earth had passed. Comets are probably composed of dis- connected meteoric bodies traveling to- gether, with so little coherence that the Sun lengthens the mass into a stream as it approaches him, Their mass is so in- considerable that Halley’s comet, due in 1759, was retarded by Jupiter 618 days without any appreciable effect on that body. Science has scattered one cause of fear since 1456, when a brilliant comet, curved like a Turkish cimeter hanging in the sky, caused all Europe to pray, ‘‘ Good Lord, deliver us from the devil, the comet, and the Turk,’’ Pope Calixtus ITI. excommunicated this comet, whereupon it went away. Nevertheless it gets cour- age to come back every 75 years. METEORIC. SYSTEMS. ** The Lord cast down great stones from heaven upon them unto Azekah, and they died.”’—Josuua, Looking into the clear heavens almost any night we may see a bright light sud- denly appear, dart a few degrees across our vision, and as suddenly disappear, or burst into detonations and coruscations, and pelt the Earth with stones of various sizes, from very small to 30,000 pounds weight. In November, 1831, 1832, and 1833, three successive showers covered an area of 1,000 miles long by 500 miles wide. A man counted 650 in fifteen minutes. The shower lasted seven hours, and 273,000 might have been seen from a single point. The cause of this display is the darting of stones of various sizes, at great veloc- ities, into our atmosphere. Their force is turned to heat, the air and themselves set on fire; and they either pass out of the air, cool off, and disappear, or dissipate in the fervent heat, or burst and descend as solids to the Earth. Over 2,000 were collected from a small area in Normandy in 1803, the result of a single shower. These innumerable bodies seem to METEORIC SYSTEMS. 41 flow in streams, like motes in a sunbeam, in regular orbits. Leverrier, whose spirit passes into the upper heavens as I write these pages, computed that the period of the meteor stream of 1831, 1832, and 1833, was 33¢ years; but the stream that flowed along the orbit was so long that the earth went through it for three successive years. Some of the streams may flow over the entire length of the whole orbit. The position and direction of over 100 of these meteor streams is already known. Others are liable to be added to our system from surrounding space at any time by the attractive pow- er of the Sun or distant planet. Thus comets or meteor systems seem closely related. Where the separate bodies are near enough to be visible in the sunlight they are called comets. Thus their tails can expand, contract, or disappear; or even the whole body be so extended as to become invisible. THE FIXED STARS. “Is not God in the height of heaven? and behold the height of the stars, how high they are!” In aclear night the heavens seem like a vast dome studded with stars. They appear to rise in the east, and sweep like a mighty army, perfectly disciplined, to- ward the west. If each left its line of march, marked by a tracery of golden fire, we should have a dome of parallel lines in perfect circles. All these would be con- centric near the north polar star. And if we should go south of the equator new stars would appear circling in another dome, and all concentric at the south pole. All these stars seem to be at the same distance. If we take our telescopes, that detect a convergence of Io inches in 300 miles, and from opposites of the Earth point two of them at the same star at the same instant, they both make the same angle; the lines do not converge. Then we observe a star at a given date, and wait 6 months till the world has whirled across its orbit, and the base line is not 1o inches nor 8,000 miles, but 184,000,000, Then we observe the star again, but it is THE FIXED STARS. 43 the same angle still. That is, the Earth’s orbit, 184,000,000 of miles wide, seen from a star would appear a point. But hold! we discover that there are a few stars that appear to show signs of parallax, 7. ¢., showing different angles from the two sides of our orbit. Suppose we measure the inclination of these telescopes on a mural circle 30 feet in circumference. We divide every circle into 360 degrees, each degree into 60 minutes, every min- ute into 60 seconds, in all 1,296,000 divis- . ions of the circle by seconds. Each of these will measure on a 30 foot circle 00027 of aninch. Of course they can be read only bya microscope. But the great- est parallax of any star yet discovered is that of a centaurz, which is only o'"9, one tenth less than one second. This gives a _ distance of 20,000,000,000,000 of miles, or a light journey of 3} years. The nearest star in our northern hemisphere is 61 cygnz, which has a parallax of 055, which gives a distance of 61,000,000,000,000 miles, a journey for light of 7} years. Sirius, witha parallax of o'°15, is twice as far. The mind of man is as incompetent as a babe to appreciate these distances. No tele- 44 STUDIES OF THE STARS. Scope ever enlarges a star from a mere point to a disk. DOUBLE STARS.—When a telescope of high power is applied to some stars they divide into two; as two lights which far off appear as one, may be discerned to be two on nearer approach. This might hap- pen if two stars were in the same line of vision, and had no relation to each other. They are called double stars when. they are related together and revolve about a common center of gravity. The Pole Star is double; Sirius also. The second one, in the tail of the Great Bear, Mizar by name, is also double. The eye sees Alcor very near Mizar, but that is not its companion. Every one knows the Great Dipper, the | end stars pointing very near the North Star. Imagine a line drawn from the Pole Star to the star Megres connecting the handle and dipper. It will be 36° long. ‘ At the Pole Star erect a perpendicular to this line 52° long, and you come to Vega, one of the brightest stars. 2° from it— the Pointers being 5° apart—and 2° from each other, will be seen two faint stars making, with Vega, a triangle nearly equi- lateral. The northern star can be seen 1HE FIXnv STARS. 45 double with an opera-glass. With a first- class telescope it appears quadruple. There are over 6,000 of these double stars already discovered. It is not good even for stars to be alone. Our law of attraction tells us that two suns near each other in fact—not merely in line of vision—must be attracted to- gether unless attraction is counterbal- anced by revolution about a common cen- ter. Eagerly we watch to see whether they revolve or rush to ruin. Yes, truly, they are seen in revolution. One pair in the left hind paw of the Great Bear has made an entire revolution since it was ob- served. Its time is 60 years. The set called Mizar has a period of 200,000 years. Of the quadruple star we found near Ve- ga, one pair revolves in about 4,000 years, the other pair in about 12,000 years, and the two pairs whirl about their common center of gravityin about a million. Add to these suns, planets, satellites, comets, and meteors, and complexities result that no mind but the Infinite can pierce. All observers have noticed that stars differ in color. About one half are white, giving all the colors of the spectrum, 4 are 46 STUDIES OF THE STARS. yellow. About 100 are red, and a few of a blue tint. It is probable that all va- riations from white result from the pres- - ence of absorptive vapors cutting off cer- tain colors. The two members of double stars always differ in color. One is orange, the other green ; one is yellow, and the other a sapphire blue, etc. A planet revolving between them may have a rosy day, followed by a purple twilight, and a night of sapphire blue. Earth is full of variety. The same Creator flashes such life along the starry arteries that the si- lent spaces. respond in blushes of rosy light, and changeful scenes of varying beauty. VARIABLE STARS. _-Draw a line from the Pole Star to the Pleiades, stop 25° before reaching them, and to the west curve four faint stars and one bright one in Perseus. 15° degrees east blazes Ca- pella, with the little triangle of the kids just below. Follow. down the line from the pole about 6° farther, turn to the west the same distance. There is Algol. For 24 days it is almost as bright as any star. Then in 3} hours it fades away and is lost to sight. Then in 34 hours regains THE FIXED STARS. 47 its former brightness. It throbs like a pulse of light, seems like a living eye flash- ing and growing dim, Draw a line from Capella through the Pleiades, and continue it as much farther, and you will come near Mira, the Won- derful. For half a month it is almost as bright as any star; then for three months it fades away, is lost from sight entirely. But after 5 months its resurrection morn- ing comes, and in three months again—a year in all—our Wonderful is in its full glory in the heavens. The star Megres has been losing its brightness for a cent- ury. Our own Sun ‘is a variable. star having a period of 11 years. TRANSIENT STARS.—During the past century 10 new stars have appeared. Whether the work of new creations, or the reappearance of some star lost before our time, we cannot tell. During the same period 13 stars, have disappeared. Some seemed to be on fire, as if they, and their attendant worlds were consumed with fervent heat. These little systems have their day ; They have their day and cease to be: They are but broken lights of Thee, And thou, O Lord! art more than they —TENNYSON, 4 THE SUN’S MOTION IN SPACE. ““His going forth is from the end of the heaven, and ~ his circuit unto the end of it.””-—Davin, The Sun does not rest quiet in space it has a going. And as all celestial mo- tion must be circuitous to safety, or recti- linear to ruin, the Sun has a circuit and safety. The Earth and the Moon go for- ward as they revolve. The Sun, with all its moving planets, asteroids, satellites, and streams of cometary matter, moves ‘on from one end of heaven to the other. About 17° ahead of Vega may be seen an irregular quadrangle of stars, some 10° long north and south, 7° on the north end and 4° on the south end. The stars of this region seem to be getting farther apart by reason of the solar system ap- proaching at the rate of 8 miles a second. The stars at the opposite point of the dome seem drawing together, like the rails behind a flying train. Other suns are also in motion. ‘In 36,000 years the handle of the Great Dipper will be broken to a right angle at Mizar,.and Dubhe will have fallen’ from No? THE SUN’S MOTION IN SPACE. 49 the opposite end, making the seven stars into the form of a gigantic S. But where is the Sun that sways suns, as the Earth does the Moon? Madler of Dorpat announces that the star Alcyone, one of the Pleiades, is the central sun of our Sun, and many others, The Royal Astronomer of England does not regard this as proved; but still it is very prob- able. It gives our Sun and its worlds an orbit of 20,000,000 of years.. The vast machine, with flaming suns as rolling wheels, is not likely to vanish just yet. The time of a single trial revolution is in- comprehensible to man.. When God was .testing Job’s wisdom and strength, he asked him if he could bind the sweet in- fluence of the Pleiades. Job did not know they had any influence. But when we _ come to see that they bind the universe together, and float innumerable great worlds as easily as the wind floats bubbles, that they reach over a distance that it takes their light 700 years to travel and control the movements of all worlds with infinite exactness, then we see that the question is not merely an expression of infinite power, but of infinite wisdom as well. NAMESAND POSITIONS OF PHESTARS: “ Tell the stars, if ¢hou be able to number them.” ** He telleth the number of the stars; he calleth them all by their names.”’ It is worthy of much pains to learn the names and places of the stars. We shall be uttering some of the same sounds by which God calls their names. They will seem like familiar friends, and will shine lovingly upon us when thousands of miles from other friends and from the earth. Of the uncountable millions let us learn afew. Beginning at the end of the han- dle of the Great Dipper, we have in order ° Benetnasch, Mizar,. Alioth, Megrez,—the junction,—Dubhe, Merak—last two, “the pointers,”” 5° apart—and Phad. 189 for- ward of Dubhe is the Bear’s Nose, and three pairs of stars, 15° apart, below, show the position of three feet. Follow the Pointers 30°, you see Cynosura, or the Pole Star. 4 stars besides it make the curved up handle of the Little Dipper, in Ursa Minor. Between the Two Bears, 13° from Megrez and 11° from Mizar, are two NAMES OF STARS, 51 stars of the tail of the Dragon. Fol- low a curve of 15 stars, doubling back, to a quadrangle 5° to 3° on a side, 35° from the pole, for his head. Tongue runs out to a star, 4° in front. From Megrez, through Cynosura, and as much farther, you see five stars as an irregular w, which is Cassiopeia. 32° far- ther is Alpherat, in the square of Peg- asus. Sides, 13° to 16° long. Pass the diagonal star and there are two stars, 8° and 9° for the neck of the horse, and one at right angles, 6° west, for the nose. Alpherat is also the head of Andromeda. Nearly diagonally to the square are three stars in line from Alpherat, 7°, 14°, and 26°, The first one, and a star on each side, are in the breast; the second, and two at the west, are in the belt. Just above the third is a nebula, barely visible to the naked eye. The third is in the foot, 10° farther in the same line is the seg- ment of Perseus; and # of the cistance between, and 8° east, is Algol again. The Pleiades fix the shoulder of Taurus; the Hyades, shaped like a V, with Alde- baran burning on the eastern point, his nose and eyes. Follow the lines of the 52 STUDIES OF THE STARS. V 16° further. Two stars 7° apart, nearly in line between Capella and Betelguese, mark the tips of his horns. From the Pleiades, through Aldebaran, and 15° far- ther, is Bellatrix, 2d mag., in the left shoul- der of Orion; Betelguese, Ist mag., is 74¢ east. 26° E. of this is Procyon, in the Little Dog; and 26° S. of this, making an equilateral triangle with Betelguese, is Sirius, in Canis Major. 16° east of Pro- cyon are the seven stars of Hydra ina compact cluster, the four brightest being a trapezium. South of Bellatrix are the bands of Orion, and bright Rigel in his upraised foot. At the lower foot is the irregular seonsutecacagrast 3° by 54°, of the Hare. Betelguese to 2°S. of Aldebaran 219, then 35° farther are three stars in the head of Aries. From Procyon, 24° toward the Pole, are Castor and Pollux, second magnitude, 54° apart. From Megrez to Pole, 36°, then perpendicularly to that line 52°, is Vega, already known. 16° south-east, passing at 9° the circular nebula, is Albi- reo, in. the bill of the Swan. Lying north- east thence are tne six stars of the Swan, making quite a perfect cross, 20° long by NAMES OF STARS. 53 17° wide. The second star from the foot is variable. 20° east by south of Albireo, 34° from Vega, is Altair, in the Eagle, the middle star of three in a line 6° long. Observe the double curve of five stars 17° long. south from Altair, That runs through Antinous. 11° north-east from Altair is the diamond form of the Dol- phin. From the Pole pass Vega, and 65° be- yond is Sagittarius, the little Milk Dipper on his breast, his bent bow 9° to the west. From the Pole by the star in the tongue of the Dragon 37°, thence 14°, almost touching the trapezium in the loins of Hercules, then 24° farther, 75° from the Pole, we see two second magni- tude stars, 5° apart, which are in the heads of Hercules and the Serpent Bearer. 38° farther and we find two faint stars in the Serpent Bearer’s foot, 15° east of Antares, which is 32° west of the Milk Dipper, and in the magnificent constella- tion of Scorpio. 20° west is the square, 6° by 9°, of Libra. From the Pole by Mizar 35°, then 35° more and Arcturus is 14° east, then 40° farther is Spica, first magnitude, in Virgo. 54 STUDIES OF THE STARS. From the Pole by Megrez and 30° farthet | is the bunch of Berenices’ hair. From the Pole through the middle pair for the Great Bear’s feet, and 30° farther, is Regulus, in the shoulder of Leo. It makes the end of the handle of the sickle that curves to his nose. Nearly half way to Arcturus, and 2° out of line, is Denebola in the lion’s tail. It makes an equilateral triangle with Spica and Arcturus. In touching these few points we pass innumerable evidences of that motion that makes the heavens alive, pass double and variable stars by the thousand, and nebule made of countless suns, till we exclaim with Job: “Lo, these are but parts of his ways; a mere whisper is heard of him. Who can understand the thunder of his power, who by his Spirit garnished the heavens ?”’ The innumerable stars Shining in order, like a living hymn Written in light. —WILLIS, TEST QUESTIONS. What is the Sun’s diam, ? time of axial revolution? How many Earths equal his bulk? mass? What of the size, appearance, and periodicity of the Sun’s spots? Give the velocity of light. Illustrate it. What two laws are stated? Illustrate each. How are the con- stituent elements of a light-giving body discovered? What two laws of gravitation? Why would a man weigh two lbs. on the Moon and two tons on the Sun? Explain the cause of the curvilinear motion of the Earth. Illustrate the delicate balancing of worlds. Give names of planets in order. Distance from Sun, and other facts in the table, at least of the Earth. What would be the relative size, and distance, of the planets, if the Sun be represented by a globe two feet in diam.? What of the heat of Mercury? velocity? Explain the apparent retrograde motion of interior and exterior planets. How is the Earth’s circumference measured? How long would it take a locomotive to run to the Sun? Describe the Moon’s orbit. Surface. Mountains, Why is not the Sun eclipsed at every new Moon? What are the causes of the tides? of their variation? What caused men to hunt for the Asteroids? What is Jupiter’s relative size? Why is he so oblate? How is velocity of light measured by Jupiter’s moons ? What is the comparative volume of Saturn? What of facts concerning his rings ? What anomalous fact concerning Uranus’s moons? What led Leverrier and Adams to seek for Neptune? What of the light and temperature of Neptune? Give six facts of comets. The history of Biela’s comet, Of what are they probably composed? What are meteors? f how many meteor systems have we defined the position ? How is the distance of fixed stars determined? What ones do you know the distance of ? How many double stars can you name? How many can you point out in the sky? What is the period of their revolution? What of the color of stars? What of the variable star Algol? Mira? How many stars have appeared in a century? disappeared ? What is the proof of the Sun’s motion? What is its period? velocity? There are given here the positions and names of 25 stars and 30 constellations, How many can you show your friends? STUDENT’S OUTLINE. THE SUN. r. Diam. 2. Revolu. 3. Comp. Earth. 4. Activ. s. Hydro. 6. Spots. 77 Motion of. LIGHT. x. Veloc. Illus. a@. J¢ sec. &. photo. c. fr. stars. da, waves. 2. Sig. material. iron, etc., in sun. é. Alde. c. Sirius. 3. Inten. illu. a. dist. Ii2: #, size of suns. GRAVITATION. 1st. law. masses. 2d. dists. @. grav. on moon, 4, sun. ¢. near earth, far sun. @. law of curv. motion. ¢. of equipo. THE PLANETS. x. Hangono, 2. Names, 3. dists. 4. Rel. size. 5. speed. 6. ellipse. MERCURY. x, Diam. 2. heat. VENUS. x. Bright. 47°. 3. rain. 4. phases. 5. Appar. retrog. EARTH. x. Dist. 2. Diam, Po, and equa. 3. eclipses. 4, meas. circum. 5.to sun. 6, burnt hand. 7. moon. 8. Dist. g. diam. 10. motion, 1x. surface. 12. path. 13. eclipses. 14. tides, 15. danger? MARS. a. lixe earth. 2. so near, so far. 3. moons. a. salt, : illum. 3: 4. JUPITER. 1. Dist. 2. Diam. 3. mass, 4. swift rota.’ 5. light meas, 6. self lu? SATURN. x. Dist. 2, Diam. 3. mass, 4. Rings. 5. change. 6. moons, URANUS. 1. Dist. X Earth’s. 2. moon’s rev. NEPTUNE, t. How found? 2. cold, 3. mnemo. COMETS. 1. var. dist. 2. speed. 3. aids dec. 4. Nos. 5. not dense. 6, meteors fr. METEORIC SYSTS. 1. wt. of. 2. Nos. 3. in streams. 4, 1831-2-3. 5. are invis, comets. FIXED STARS. _ I. concen. circles. 2, Three baselines,’ 3. 27% /” 4. near stars. DOUBLE STARS. Pole. Mizar. Sirius, Near Vega. revolve, color. VARIABLE STARS. Algol. Mira. Time. TRANSIENT STARS. 10 new—1z3 lost. SUN MOVES. Toward Her. Star drift. Bind Alcyone? Best Books for Further Study. The most perfect machinery and the deep est study of the race have been employed on astronomical research. Study RECREATIONS IN ASTRONOMY. With di- rections for Practical Experiment and Tele- scopic work. 84 illustrations and maps of all stars. By Henry W. Warren, D. D. Price, $1 50. The latest discoveries are de- tailed in the most interesting and intelligible manner; and the stars are so mapped that their names can be easily determined. POPULAR ASTRONOMY. Lectures by Prof. _O.M. Mitchell. Price, $1 50, An excellent description of some fine astronomical instru- - ments. Ecce Ca@Ltum. By E. F. Burr, D.D. Price, $1 25. HALF-HouRS WITH THE ‘TELESCOPE. Prof. R. A. Proctor. Price, $1. And Pro- fessor Proctor’s other works. The best popular Atlases of the heavens are Burritt’s—price, $1 50—and Proctor’s New Star Atlas. Price, $2 50. Celestial Globes from six inches, price, $5, to 18 inches, price, $75. Study the Almanac for the places and changes of the planets in sight. Keep ac- quainted with them and their movements. i ager a ap in ( hes Pret - ide oF crane ’ iy na ; hte | ) Bane 3th RY AW not iy y din va y { a Ghia he A) aie Ti ma ae iC " 4g aye FDL ae Sf ae tog ies Me" Ws iy Pee hs AY RI iree Library U. Of i. At Urbana-Champaign