:-NRLF OF THE H \ UNIVERSITY I OF / The Great Nebula in Andromeda, from a photograph by Professor G. W. Ritchie of the Yerkes Observatory. RADIANT ENERGY AND ITS ANALYSIS ITS RELATION TO MODERN ASTROPHYSICS BY EDGAR L. LARKIN DIRECTOR LOWE OBSERVATORY KCHO MOUNTAIN, CALIFORNIA Fellow of the American Association for the Advancement of Science Member of the Astronomical Society of the Pacific Fellow of the Southern California Academy of Sciences ILLUSTRATED " Many thousands of unrecorded nebula.' exist in the sky. A conservative estimate places the number within reach of the Crossley reflector at about 120,000." /awes E. Keelc, . " Darkness there was, and all at first was veiled in gloom pro- found, an ocean without lig^it." Ri<; feda, loth Ch., Hymn i2i>. .*- " :^5^. fV O c THE \ t V ' M ' ) / L9O3 BAUMGARDT PUBLISHING COMPANY LOS ANGKLKS, CALIFORNIA COPYRIGHTED 1903, BY BAUMGARDT PUBLISHING COMPANY, L,os ANGELES, CALIFORNIA TO JOHN D. HOOKER WHO IN THE MIDST OF THE PRESSING DUTIES OF A BUSINESS CAREER STILL FINDS TIME TO DEVOTE TO SCIENCE AND ITS ADVANCEMENT IN SOUTHERN CALIFORNIA THIS BOOK IS DEDICATED 175084 INTRODUCTORY. Upon coming to the Pacific Coast, the writer was engaged by Dent H. Robert, editor of the San Francisco Examiner, to contribute a series on modern physical science. The subject se- lected was, "Radiant Energy and Its Analysis," together with its application to astronomy and astro-physics the latter being an entirely new branch of research into the laws of nature. The text as it appears here, and also the cuts, appeared in the Ex- aminer, from February to August, 1902. The writer re- ceived so many letters on the subject matter of the series, and upon the discussions therein and questions involved, that it was desired that the whole should be published in book form. The matter was considered by the officers, William H. Knight, Presi- dent, and r>. R. Baumgardt, Secretary, and many of the mem- bers of the Southern California Academy of Sciences. No funds were in sight, so the Vice-President, J. D. Hooker, came to the rescue and said he would see the book through the press. For this, he not only has the thanks of the writer, but of the mem- bers of the Academy also. Special regard is gratefully accorded I NT ROD UCTOR Y to those two eminent women, the Misses Matilda H. and Jennie M. Smith, of Allegheny, Pennsylvania, for their beautiful present of a spectt-ograph and heliostat. These splendid instruments were made by that accomplished mechanic, John A. Brashear, of Allegheny, and presented to the writer upon their order. Here is a case where two wealthy women devote their time and means to the cause of science and the aid of research into the most inscrutable laws of the natural world. To the Baumgardt Publishing Co. is due the credit of a perfect publication, in composition, arrangement and high-class press work. Thanks are tendered to Mausard, Collier & Co. of Los Angeles for their fine production of many of the cuts. In many cases the originals were very poor, some scarcely legible. The Lick Observatory, Mount Hamilton, Calif., also kindly fur- nished the pictures of their telescope and spectrographs. Thanks are due to Professor E. E. Barnard of the Yerkes Observatory for the exceptionally fine graphs of the Milky Way and of the great Nebula in Andromeda, as well as of the tele- scope and spectrograph in that observatory. The graphs of the solar prominences secured on the eclipse expedition are of great beauty and perfection. These pictures were prepared by Ferdi- nand Ellerman, the observatory photographer. Acknowledgements are due to William H. Knight of Los Angeles for reviewing the work, critically examining the whole and noting imperfections. Since the beginning of the series, the astro-physicists of the world have made many more researches and discoveries. Enough material is now on hand from all these to fill another volume INTRODUCTOR V like this. The scientific brain of the world is in a state of in- tense activity, the most recondite and elaborate studies are under way and knowledge is moving with ever-increasing mo- mentum. The most skillful detectives of nature are at work hourly in every possible way, striving to find out what matter is, and also energy. At present both are unknown ; they may for- ever remain unknown, but if it can be proven that they are un- knowable, this at least would afford a resting place for wan- dering thought, wandering along the borders of infinity. EDGAR L. LARKIN. RADIANT ENERGY. i 7 I. RADIANT ENERGY. "Our fathers resorted to Indra of old : they discovered the hidden light and caused the dawn to rise." Rig Veda. Muir's Sanskrit, Texts 39-2. I 48, 14. Radiant here means proceeding from a center in straight lines in every direction. Energy is internal and inherent. Professor Barker, Physics, page 4, says : "Energy is defined as a condition of matter in virtue of which any definite portion may effect changes in any other definite portion." This was written in 1892, and discoveries since confirm it. Energy, then, is a state of mat- ter, or, rather, the result of a particular state or condition in which matter may be when any observed phase of energy appears. These two, matter and energy, or, possibly one, is the sum total of all that has been found during three centuries of incessant research in all that portion of the universe visible in a forty-inch telescope armed with the most powerful spectroscope ever made. It is the belief of the writer that all this space is saturated with inconceivably minute corpuscles, those recently discovered by Professor J. J. Thomson. These are doubtless either electricity in its ultimate refinement, or very closely allied to it, or its imme- diate carriers. The smallest particle of hydrogen, long time called an "atom," has been thought to be the least in mass of any known particle of matter; but the corpuscles detected by Thomson have 'S RADIANT ENERGY. only one-thousandth of the mass of the hydrogen atom. The earth and sun, all suns and dark bodies in space, all granular mat- ter move through the primordial cosmical mass of electrical cor- puscles as would a wire screen through water. The wide spaces in diamond, glass, steel, flint or anything else allow these "bodies smaller than atoms," as Thomson calls them, to pass through. From the record-breaking discoveries of the physicists Curie, in previously unknown waves, it is coming to be seen that all matter is radio-active. All phases of matter, such as radium, barium, uranium, thorium, polonium, vanadium, cereum, molyb- denum, zinc, aluminum, etc., emit obscure undulations, and these imprint radiographs on sensitive photographic plates. Radium is so active that its potential has been measured and with a delicate watt meter its power has been 'determined. Thom- son's corpuscles are plus and minus in their electrical charges, the positive carriers of electricity being comparable in size to ordi- nary atoms of gross matter; but the corpuscles that flow between the atoms of all types of matter are negative. The corpuscles emitted by radium are negative and can be bent out of their course by the plus pole of a magnet so that active matter sends out per- petually the same kind of corpuscles that fill all space. It is incredible that these radiating bodies forever emit corpuscles without receiving them from the primeval store. Therefore radio- active masses are simply more transparent to corpuscles from space than others, or change their directions of motion. The fact that negative ions can be deflected by magnets is one hidden deep in the end of a long corridor in nature, a passage more inscrutable than those in the Pyramid of Suphis. TRANSMISSION. From the definition of energy it is the potential of the uni- verse. When matter is in a phase allowing it to be active, it efTects other quantities of matter at a distance. The method of 7? A D I A N T E N ERG Y. i 9 transfer is known to be by means of wave motion. Each impulse moves from the emitting to the receiving mass on a rigorously straight line. One continuous set of oscillations in this right line is called a ray. Each negative or Thomsonian corpuscle makes a double vibration to and fro like a pendulum straight across the direction of the ray i. e., at right angles to it, the corpuscle moves over and returns to its original position had before the excursion. Since the corpuscles are negative and can be drawn out of their original straight path by the action of magnetism, the entire wave motion of the universe is electro-magnetic. This is what Maxwell prophesied forty years ago. Thomson fulfilled the prophecy. Cut 1. Waves. After one corpuscle makes an oscillation across the direction of the ray and return the next does likewise, and the next, and so on. After the first corpuscle makes swing, another distant from it 186,000 miles in the same straight line will also make a vibra- tion at the end of the first second of time. In figure I, cut I, the distances of the sides of the waves from the central straight line of the ray is amplitude, or the distance each corpuscle swings on either side. Since each wave must be distant from its source, 186,000 miles at the end of one second, it follows that variations in the lengths of the waves occur, those having the greatest amplitude being the longest 20 RADIANT ENERGY. that is, a less number will be contained in a centimeter, as shown in diagram. Really there is no such thing as a ray ; the straight line along the middle of each set of waves was simply drawn to show direction of the waves and to show the amplitudes on either side. A cannon ball carries matter and energy while corpuscular disturbances transmit energy from an active phase of matter to a passive or receiving, non-vibrating phase. If one inch contains from 34,000 to 61,000 electro-magnetic undulations, their effect on human sensation is called LIGHT. With 34,000 to the inch, everybody agrees in saying they see red; if 61,000, violet, with an indefinite number of colors between. Cut 2. Dark Room. L,ight Entering from Sun. For physicists to examine the properties of light it must be first bent out of its course. The best place to work is in a dark room, where all light is excluded except one pencil of waves admitted through a minute opening. In cut 2, a band of light is shown coming from the mirror of a heliostat. The bundle of waves crosses the room and makes a bright image of the aperture on a white screen. The heliostat mirror is turned by a clock one way as fast as the earth turns the other, so the light is in the room from sunrise to sunset. That is, the sun seems to be at rest in space, hence the name of "sun standstill." RADIANT ENERGY. 21 TURNING WAVES OUT OF THEIR COURSE. In figure 3, of any transparent substance is placed in the beam of waves at right angles to it as at A, no effect is produced ; the white spot is still seen on the screen. But incline the transmit- ting body as at B and a marvelous thing is seen the bright spot moves aside. This has elicited the admiration of every physicist from Newton to the present. It is a fundamental rock-hewn foundation stone of nature. Without it no telescope, microscope, camera or spectroscope or any lens whatever could be made and men would now be in complete ignorance of the universe round about. The waves at I are incident, at R refracted, and KCO/V( Cut 3. Refraction of L,ight by Inclined Medium. at E emergent, but the entering and leaving bands are parallel ; the emergent line of waves being bodily shifted aside, their motion coming to an end in the bright spot C, having moved from D. This phenomenon is called refraction to bend or break. The diameter of the bright dot on the screen, however, is the same at C and D. The light yet is not in a condition to analyze. Instead of putting a flat medium with parallel lines in the waves as at B, insert one with inclined sides as at P, figure 4. The emergent band instantly widens, the bright spot vanishes, a broad and long band of light containing every color from red to violet flashes on the screen. It is the 22 RADIANT ENERGY. SOLAR SPECTRUM, one of the most impressive visions ever seen by the eye of man, and is now known to be one of the most valuable of human possessions. This separation by inclined surfaces of a transmit- ting medium is termed dispersion, or separation of all the differ- ent wave lengths, the shortest waves violet sensation being bent aside, dispersed or removed to the greatest distance from the original straight line the incident pencil while long waves red are turned aside the least, with every other light wave be- tween, the phenomenon being classed under the head of different refrangibility, or of varying rates of refraction, for dispersion Cut 4. Dispersion of lyight by Medium with its Inclined Sides a Prism. is not a physical fact' in nature by itself, it being merely refraction. Since 1859, when Kirchhoff laid the foundation of modern spec- troscopy, many of the most refined intellects of the world have studied incessantly the properties of this glorious band of colors. Indeed, only one line of research ever undertaken by man has exceeded it in intensity of thought the calculus. Today there stands a majestic science, profound in its conclusions, far-reach- ing in its determinations, approaching sublimity in its deductions regarding the composition, construction and potential of the uni- verse. It is spectrum analysis. Let its study be continued, R A D I ANT E N B R G Y. 23 II. SPECTRUM ANALYSIS. By the radiant light of the universal magnetic ocean, electric waves bind the cosmos together." Veil of Isis, Vol. i, p. 282. The reason why the colored band the spectrum is so valu- able is that in it the waves are separated. Each length of oscilla- tion is by itself and in a state suitable for measuring-. Also the properties of each wave can be studied in their reactions on each other, and what is of great importance, the action of each kind of vibration on gross matter. Our lives and existence on earth depend entirely on these waves, also the only knowledge so far secured regarding the universe and the earth's place and man's place therein has come from three centuries of study of these tiny undulations. Waves therefore constitute a fundamental fact in nature, and should be studied bv all who have the slightest regard <*> o for nature and her works. Every operation in the natural world round about is carried on by the most rigid and inexorable law. LAW I. All solids, liquids and gases, under great pressure, project continuous spectra when incandescent. This is one cornerstone in that majestic edifice, spectrum analysis. 24 R A. DI ANT U N ERG Y. BUILDING UP A SPECTRUM. In cut 4, stop the clock of the heliostat and place a hot iron in front of the mirror, between it and the prism. Hold the hand near the iron, heat is the sensation imparted by the black mass. It is at once known that the iron is emitting waves. They are invisible, being too long and too slow in rate of vibration to act on the retinal nerves. Heat the iron hotter ; watch closely and dull red will appear. Increase the heat ; all shades of red will develop, from dull to bright. Millions of different waves differing in lengths and rates will be seen. Reflect the rays through the prism, look on F1C.I. ONLY RED RATES 'APPEAR. VIOLE.TI its&i&o BLUE c^m YELLOW ORANGE RU FIG-A ALL 8ATE.S- SPUTRUM CONTINUOUS FIC.-3 SPtCTRUM WITH 7 RATtS Cut 5. Three Spectra. the white screen on the other side, and figure i, cut 5, will flash out. A band of red light will be seen extending from deep to bright red. This is because it emits only red rays ; not being- hot enough i. e., its internal particles do not oscillate fast enough to send forth any other lengths of waves. It is said that the metal is "red-hot." For deep dark red, one inch contains 33,000 waves, and for deep low musical notes in a piano, vibrating 32 times per second, the wave length is thirty-five feet. So one deep bass wave from an organ is 13,860,000 times longer than a bass wave of light called red. R A D I A N T B N H R G Y. 25 Heat the iron still hotter, it begins to lose its red color and be- comes white. Look at the screen, then figure 2, cut 5, will be seen. It is a continuous spectrum, continuous because all wave lengths, all rates, are present. And these rates of vibrations are colors. For color in light is pitch in sound. Still increase the heat of the iron, it becomes a liquid, but the liquid is still white ; it emits every possible rate, and the band of color is still complete but brighter than before, because the liquid iron is whiter than solid. But, during all this time, great events are happening outside the visible spectrum beyond the violet, in that mysterious region called the ultra-violet, now being explored with feverish anxiety by physicists to find more invisible rates in waves, and they are being discovered almost daily. The oscillating particles of iron set vibrating by the heat, beat so rapidly that the eye cannot follow the short waves sent out, for the invariable product of swings of particles is waves set up inside and surrounding every particle of matter in nature. For the shortest violet wave just within range of acute eyes, before final extinction in the invisible ultra-violet, has length such that 61,000 are within one inch. And the highest musical sound caused by a piano wire oscillating 4,000 times per second is conveyed by a wave three and one-third inches long. Some can hear sound when the wave length is four-tenths of an inch in length, but it is not music merely a very shrill sound. Thus, all sound waves are exceedingly long compared with light waves. HARMONIES IN NATURE. A continuous spectrum is, therefore, comparable to the key- board of an organ, with every key open, the bellows being in constant action, the bellows corresponding to the continuous shining of the sun, or other source of white light. For the organ issues every musical note, and the continuous spectrum is made 26 R A D J A N T B N B R G Y. up of every harmonic (musical) light else it would not have been emitted by a white source. And this is why the musical is called the color or chromatic scale. Harmonics lie deep in nature, and their study has developed into a vast complex and mathe- matical science. But before the dark mass of iron became en- dowed with the swings or excursions to and fro of its particles rapid enough to emit dull red, it was at work in an invisible region beyond the red in issuing long, slow, heat waves, all too long and too slow to have effect on the retinal nerves. But that marvel, the bolometer, contains a platinum nerve of exceeding delicacy and this detects the long waves far and away beyond the limits of the slowest red. The fast short waves be- yond the most rapid violet are detected by the fluoroscope by slowing down rates and changing lengths, while the gelatine- bromide plates clutch the waves in space by the million and holds their energy fast in particles of silver. And the rapid and slow invisible portions of the spectrum are at present explored to about sixteen times the length of the visible, thirteen times in the ultra- violet and three times in the infra-red. So human nerves are not as sensitive as might be supposed, for platinum and silver are both more sensitive. Now by a complex process, heat the liquid iron hotter than ever, turn it to gas and confine it if possible like vapor of water in a boiler, and look again upon its spectrum projected by prism on screen, behold ! it is continuous still, for white hot gas emits every color, or rather every rate as well as white hot liquids and solids. This is as might be expected, for the source of everv color is white. This, therefore, is a repetition of Law I. Now, after the terrific heat is in full activity, after the iron panicles have been by it endowed with repulsion sufficient to tear them apart, forming a true gas, then release the pressure. At once the iron particles fly to immense distances apart compared with their diameters, and swing to and fro with inconceivable rates, RADIANT ENERGY. 27 in paths termed their own free paths of oscillation. But when all pressure is removed, so that the gas can expand and have plenty of room for its particles to make their own unconfined vibration, a marvelous thing happens ; an action occurs that rilled the minds of all physicists with admiration, wrought mighty changes in human concept of the structure of nature, enlarged the shoreless sea of knowledge, and inspired all who studied these things with enlarged ideas of the laws and magnitude of the sidereal universe. At the instant in which the particles of iron or any other phase of matter are allowed to vibrate at their own rate a new and mighty law takes effect. LAW II. All phases of matter, when vibrating at their own rate, pro- ject discontinuous or bright line spectra, no two sets of lines being alike. This is another cornerstone upon which stands the temple of nature. When the iron gas is vibrating in fervent heat the appear- ance on the screen is shown in figure 3, cut 5, where all continu- ity in the spectrum has vanished, a series of bright lines alone remains. All the rest of the band is now dark, no light wave ap- pears save those making up the bright lines. And each phase of matter known as iron, zinc, tin, palladium, hydrogen, aluminum, thorium, strontium, thaliium or any other, projects an entirely different set of lines from all the others. Each series falls in the 1 same measured place in the spectrum. These lines are the most valuable element of knowledge and their discovery and method of producing them was one of the most remarkable achievements of man. They make up the alpha- bet of the universe, and spell out messages from our own and other suns, and can be read by an expert as well as the Morse dots and dashes in the telegraphic code. So now the current life events of the sidereal hosts in space are being read daily like a 28 RADIANT ENERGY. newspaper, and not only read but recorded for future genera- tions of men by that other marvel the spectro-camera. The long dark band to the left of the red in figure I, cut 5, need not have been drawn ; its place is to show where the continu- ous belt of colors would have been had the light source been white, as in figure 2. The bright lines in figure 3, said to represent the iron spectrum, is tentative, for iron casts about 480 lines. So far no instruments have been mentioned save a hole in a shutter, dark room, prism and screen. The spectroscope itself must now be taken apart, each piece photographed and presented for study. RADIANT ENERGY. III. THE SPECTROSCOPE. "Arise ! the breath of our life has come ! The darkness has fled. Light advances pathway of the sun." Rig Veda, 1-113. Muir's Transla- tion. Since the corpuscles of every phase of matter when oscil- lating at their own rate traverse without hindrance their own free paths, in which case they must be separated (exist in a gase- ous form), set up disturbances which are known as light, and project bright lines in their spectra, complex instruments must be had to analyze these emanations. The mechanism is called the spectroscope to view the spectrum. In the beginning of this comprehensive study, the spectroscope was a simple instrument, but now after half a century of added improvement, has become one of the most intricate and delicate known to science. Indeed it must be, since its work is to tell what the universe is made of. In cut 6, some of the complex spectroscopic apparatus in the Lowe Observatory is on display. The instrument to the right marked i, 2, 3, is the heliostat (sun stand still). It is outside the observatory in full sunshine ; ( i ) is the clock which turns the axis (2) and the large mirror (3) in a direction oppo- site to the direction of rotation of the earth. The sun shines on the mirror (3) and this throws a broad band of light from the sun into the laboratory through an open window. The beam of jo RADIANT ENERGY. light remains in one position in the room all day if required, the effect being as though the sun remained stationary. The axis (2) must be parallel to the axis of the earth, and exactly in the meridian, else the pencil of light would wabble around the central line. To make the axis of the heliostat parallel to that of the earth, it must be elevated above the horizon as many degrees as the heliostat is removed from the equator of the earth that is, the elevation must equal the latitude. It therefore points to the pole of the heavens. This heliostat was a gift from those eminent ladies, the Misses Jennie M. and Matilda H. Smith, Cut ('). Spectroscopic Instruments in Lowe Observatory. of Allegheny, Pa. They devote their lives to the encouragement of science. Without this heliostat the complex spectroscope would remain idle and useless in the laboratory. The ray of light passes into the narrow slit of the spectro- scope (5). This is an opening between accurate metallic jaws, whose width is variable. Thus when it is desired to see the Fraunhofer lines in the solar spectrum, the opening is narrowed to the 5ooth part of an inch, or even less. The light emerging from the slit is three-fourths of an inch high, for the slit in sun work is vertical, and the i-5ooth of an inch wide. It passes through the collimator (tube 6) and falls on a convex lens behind RADIANT ENERGY. 3 j 8, and not shown in the cut. This lens casts an exact image of the slit upon the diffraction grating (7). This grating is an absolutely flat piece of polished speculum metal. It has been ruled with an exceedingly small diamond point, with lines 14,438 to one inch. The space shown white in 7 is the ruled surface and is i% by i> inches, and therefore contains 27,073 lines, grooves cut in the metal, and as many elevations of metal be- tween. These elevations and depressions cause incident light to leave the grating by reflection in odd multiples of half wave- lengths ; that is, when the light is reflected away from the ruled surface it is in a state of interference, the waves are not in uni- son, crests and hollows, and crests and crests, interfere, and when white light makes interference darkness or colors occur. In the diffraction grating no darkness appears, but a glorious band of colors is always seen when sunlight is coming in at the slit. It is the most beautiful vision that the eye of man has looked upon. It is none other than the solor spectrum. Diffract means to break ; the white light is broken up into an infinite num- ber of different rates of vibration that is, colors. And color in light is comparable to pitch in sound. But when waves of light beat at their own rate, without obstruction from others, they not only appear under different colors, but each tint takes on its own direction, no two colors being seen coming from the same direc- tion. Hence the thin slit one five-hundredth of an inch wide, since it contains every rate, is widened into a long narrow band three-fourths of an inch high, filled with every color. The band leaves the grating by reflection and falls on the convex lens (8), in the grating end of the telescope, (8, 9). At 9 is another lens called an eyepiece, not shown in cut 6, since it is now in the hands of Brashear, Allegheny, Pa., to be fitted into a new spectograph now building. Lens 8 forms a brilliant image of the band or spectrum on lens 9, and to an eye placed at 9 32 there is revealed a magnified band of innumerable colors, long, brilliant and marvelous in what it means. But of inconceivably more importance than beauty or color, the Fraunhofer lines stand out in their majesty. There are more' than 8,000 black lines, crossing- the spectrum at right angles. Some are thin as a spider web, and others from ten to a thousand times wider. They appear in all parts of the spectrum, from the longest red to the shortest violet undulation. Their discovery and translation is the chief event that has occurred on the earth within the period of written history. About A. D. 1600 Kepler placed a prism in a beam of sun- light and saw a solar spectrum the first recorded in the annals of science. A century later Newton admitted light through a round hole in a shutter into a dark room, placed a prism in the beam and obtained a clearer band than Kepler's. At the end of another century, in 1802, Wollaston did what Newton per- formed, only he admitted the light through a narrow slit, and his was the first mortal eye to see the spectrum crossed by a few black lines. Twelve years later, Fraunhofer let in light through a slit, as did Wollaston, but happened to look at the spectrum with a small telescope an act that changed the course of science for all time and gave rise to the chief study that ever actuated the human brain spectrum analysis. RADIAN T EN ER G V. IV. FRAUNHOFER'S SPECTRUM;. "The bright one, whose powers are unequaled. The oracle, the high ruler, the southern sun." Inscription on obelisk in Palace of Nimrud. Primeval Assyrian, (Cuneiform) Talbot's Trans. Fraunhofer, with the little telescope, discovered hundreds of fine, black lines crossing the spectrum of the sun at right angles to its length. In cut 7 is shown his original and now historic spectrum of the sun, in which he mapped 576 black lines. Cut 1. Fraunhofer's Original Spectrum. Universal interest was at once awakened ; and it is a fact deep in psychology that the leading minds in Europe began intense study and labored on the spectrum from 1814 to 1859, as if impelled by resistless desire to find the cause of the mysterious lines. All realized that a magnificent law of nature was con- cealed in the spectral bands, but none could read the hand-writing. 34 RAD I A N T E N ERG Y. Neither Herschel, Young, Bunsen, Brewster and hundreds of others, nor indeed Fraunhofer, could approach solution of the cipher dispatch from the sun. P A or forty-five years a most ex- citing search was made one of the most remarkable in the his- tory of man in quest of a mighty law. Finally Kirchhoff stood up, in 1859, and announced to a waiting world the key that would translate the alphabet of nature the strange glyphs in which she had for ages striven to open up communication with human beings. Kirchhoff unlocked the gate of a labyrinth more inscrutable than that of the Egyptians ; the great doors swung on their rusty hinges, hundreds of barriers vanished as if by magic, and he peered into the long dark corridors, hermetically sealed, until he found the key. The discovery of the origin of the Fraunhofer lines is equal in importance to that of the law of gravity, for the law of gravi- tation "weighs" the universe, and the law of Kirchhoff tells what it is made of. BUILDING UP A SPECTROSCOPE. In the cut published in the third paper all parts are shown assembled into a complete instrument. Each part must be exam- ined separately to gain an idea of this most powerful weapon in the hands of man for his ultimate conquest of nature. In cut 8, figure 5, is shown the slit of a modern spectroscope as made by Brashear. It is unscrewed from the end of the col- limator tube. In the cut the slit is opened hundreds of times wider than when in use, so that it may be seen. The light direct from the sun is sent by the revolving mirror of the heliostat (cut 6) into the narrow opening. When making an examination of an exquisite Fraunhofer line, whose thickness is comparable with that of a spider web, the distance between the jaws ranges from the one-five-hundredth to the one-thousandth part of an inch, invisible almost to the unaided eye. But the powerful light of the RADIANT ENERGY. 35 Cut 8. Fig. 2, 3, Electric Lantern for Micrometer Illumination; Fig. 5, Slit of Spectro- scope ; Fig. 8, Collimator Lens ; Fig. 16, Searchlight Carbon 3,1)00,000 Candle power ; Fig. 17, Two ordinary City Arc Light Carbons. sun finds a way through it and falls on the convex lens (figure 8) in cut 8, which was detached from the opposite end of the collimating tube. The work of this lens is to project an image of the slit upon the diffraction grating. The slit is in what is called the prin- cipal focus of the lens. When any object is in this point, rays from it emerge parallel from the lens, the effect being the same as though the object (the slit in this case) were at an infinite distance. In the Lowe spectroscope the slit is five-eighths of an inch high and of any width desired. The jaws of the slit are moved toward or away from each other by screws, and the edges are as straight as can be made by human hands. If not, the lines in the spectrum would be distorted so they could not be measured with the micrometer. The slit, therefore, is a very important part of the spectroscope and corresponds to the narrow aperture 36 R A D I A N T E N E 7? G Y. in the shutter of a darkened window, employed by the early physicists in their gropings after a secret of nature, only found at the end of 250 years incessant study. The collimator is simply a metal tube fourteen inches long, with slit at one end and projecting lens at the other, the sole use of the combine being to cast an accurate and brilliantly lighted image of the slit upon the excessively fine rulings of the grating. This bright image is not magnified it is still five eighths of an inch high and of the same width as the opening be- tween the jaws. PHASES OF MATTER AND THEIR ANALYSIS. So far, these notes have arrived at the cardinal fact in nature that the solar spectrum is crossed by thousands of black lines, scattered here and there in the midst of gorgeous colors. A devious course was traversed by the human mind before they could be translated. For lines cast in the spectra of every phase of matter known, are bright, highly colored and not black. Before attacking the mighty problem of black lines in the spectrum of the sun, the bright lines must be understood. If you hand anything to a chemist for analysis, he will prob- ably dissolve it either in acid, water or other solvent, and subject the mass to the action of reagents. But the spectroscopist at once subjects the substance to terrific heat, passes the light from the resulting incandescent gas through the slit and collimating lens and allows it to fall on the grating. Each phase of matter when corpuscles are torn apart and separated far enough to allow them to oscillate, will vibrate at its own definite rate. Each oscillation of a corpuscle will cause another to swing, and another, the motion being a wave move- ment. But each wave strikes its own place in the spectrum, and sets of similar waves form the bright spectrum lines, due entirely to wave lengths and rates of oscillation. The best way to make RADIANT EN ERG Y. 37 corpuscles of metals swing* at their own rate is to force them apart by the intense heat of the electric arc. Figure 16, cut 8, is the positive carbon just as it was taken out of the circuit short!}'' after having been used in the 3,000,000 candle power searchlight on Echo Mountain. The crater is shown scooped out deep into the soft core of the carbon. In use the negative carbon is above this, separated by an air space, through which the electric arc plays with its appalling force and heat. Place the carbon points a few inches from the slit, put a chunk of metal or metallic salt or compound, flint, silicious compounds, rubies, diamond or any refractory substance whatever into the crater and turn on the current of electricity. At once the metal or anything else is turned white hot, and then to a still hotter gas, which fills all the space between the carbon point above and crater below. But, at the instant when the gas becomes hotter than white, that is, when each corpuscle is torn away from all the others, each vibrates at its own rate, and a set of brilliant lines is seen on the grating, no two sets being alike. Each set is one letter in nature's alphabet. Their positions are measured with accuracy, and waves sent from iron, titanium, helium, or any other phase always fall in their own invariable places. This is the basis of spectrum analysis. In cut 8, 17 is an ordinary city arc light carbon, with another leaning against it with wires attached. And these as well as still smaller are used in spectroscopy, they having craters large and hot enough to vaporize metals. Under the figure 5, half covering the slit is a total reflection prism, and light falling on its base is reflected by the hypotenuse into the slit. Thus two sets of lines from two metals, or from one metal and the sun can be projected on the grating ready for analysis and comparison. The tube 2-3 is an electric lantern to illuminate the spider webs in the spectro-micrometer, and will be explained when that in- strument is presented. RADIANT HN HRGY. V. "When thou seest the holy and sacred fire devoid of form, burning and flying everywhere into the depths of the universe, listen to the voice of fire." Plethon, Iranic Literature. In cut 9 a rough drawing is shown of the parts of the spec- troscope that receive light and prepare it for analysis. To the right is the upper part of the axis of the heliostat with its mirror, which is revolving from east to west to counteract the rotation of the earth. Beams of light are falling upon it from the sun and the brilliant mirror reflects them through the slit, i-ioooth of an inch in width, and projects the rays upon the lens in the opposite end of the tube. The lens forms a clear cut image of the open slit upon the ruled surface of the diffraction grating, Cut. 9. Mirror of Heliostat, Collimator and Diffraction Grating. which image is the same size as the slit, not being magnified by the convex lens, because the slit is in its principal focus. After more than a century of ever-increasing mechanical accuracy, at last a perfect image of a slit is had. RAD I A NT ENERGY. 39 It might be thought an easy matter to make an opening with sides exactly parallel and straight, but to make a straight line is a task of great difficulty. The grating is a flat piece of speculum metal, and to make a flat surface is far more trying to mechanics than to make a straight edge. The ruled surface is i i -2x1 7-8 inches and is ruled 14,438 to the inch. To rule it required several days and nights incessant work in a constant temperature room. Cut 10. Grating. Showing Incident Rays, and Wave Fronts after Diffraction and Reflection. The metal plate is three-eighths of an inch thick, and in figure 7, cut 10, is seen lying on its back, showing the groves as they were cut with a diamond point. The grating is superior to the prism in the fact that it makes a normal spectrum. Each wave falls into its proper place, which is not true of the prismatic spectrum. Cut 10A. Fig. 7 the Diffraction Grating; Fig. 13, Prism. The diffraction grating is one of the most valuable of human possessions, it has expanded knowledge more, perhaps, than any one discovery, unless the calculus may be classed with it in power. So numerous and important are the record breaking 4-0 RADIANT ENERGY. discoveries made with the grating- that its action on radiation must be thoroughly understood. DIFFRACTION AND INTERFERENCE. These will be treated as identical here ; they are cardinal facts in nature, and their study has taxed the resources of physicists and mathematicians since Newton produced diffraction rings. Light is a wave motion in the corpuscles discovered by Professor J. J. Thompson. All along a hypothetical ether was postulated to be the medium of transmission of all radiant energy but Thompson's negative corpuscles, saturating the universe, meets every requirement of the electro-magnetic theory of radiation, due to Maxwell. All radiant energy is conveyed by means of waves in cor- puscles, but it is known that waves interfere with each other. If two waves exactlv alike interfere, both are totallv destroyed. Cut 11. Fresnel's Mirrors. Drop two stones in water at some distance apart, waves will expand in circles ; in a short time the two circles will collide ; but if two similar waves in opposite phase meet, the water will be at rest and a cork floating thereon will not oscillate. If two water waves interfere, rest succeeds ; if two light waves, darkness Stillness in water corresponds to darkness in the midst of light, for light added to light may produce darkness. All this can be seen in cut IT, due to Fresnel, where 9, TO, ii 2, 3, 4 are on the surfaces of two plane mirrors hinged at the centre. Their reflecting surfaces are nearly in the same RADIANT ENERGY. 4 i straight line, the inclination angle being but little less than 180 degrees. At 5, is the radiant, a brilliant point or slit, while 6, 7, 8, is a white screen, and I is a curtain so that light from 5 will not go direct to 6, 8, and obscure the light from the mirrors. Its use leads to startling results. Let light of any one wave-length say blue radiate from 5, strike both mirrors as shown and be reflected to the white card 6, 8. One point on each mirror as 9 and 2 may be chosen so that the ray 5, 9 added to 9, 8, shall equal in length the ray 5, 2 plus 2, 8. Then a bright spot of blue light will appear at 8. This is because the waves leave 5 and arrive at 8 in the same phase. But if the ray 5, 10, plus TO, 7, and 5, 3, plus 3, 7, differ by half a wave- length, a dark spot is seen at 7. Blue waves meet at unlike phase and destroy oscillation. The hollow of one comes opposite to the crest of another, the motion of corpuscles is quenched, the waves interfere and both are destroyed. Thus the undulatory theory of light was proven, for matter added to matter cannot destroy both light is therefore not mat- ter. And there will be alternate bright and dark spaces on cither side of 6 and 8, cut n. If the radiant 5, gives white light, there will be no dark spots, but every possible color will take their places and the cause must be known or the formation of an interference or diffraction spectrum cannot be compre- hended and the secret processes of nature remain undiscovered forever. CAUSES OF INTERFERENCE SPECTRA. Figure i, cut 12, is an enlarged view of the rays 5, 10, 7 and 5, 3, 7, in cut IT. Ray 5, 10, 7, in cut 12, shows 5 waves, and 5> 3> 7> 5 l /2- They interfere and destroy each other's motion, hence a dark spot appears at 7. The corpuscles at 7 are actuated by equal motions in opposite directions. They remain at rest for the motions are in directions of the arrows. The darkness appears if one kind of light, as violet, is used, but if white light 4.2 RADIANT ENERGY. is reflected, then any color may appear at 7, which color de- pends on the angle of the light, incident on the mirrors. For the next ray to 5, 10, 7 and 5, 3, 7 might not differ by half a wave-length, and not interfere, and therefore fall on the vacant Cut 12. Enlarged Rays from Cut 11. space filling it with its own color and so for all the countless millions of waves of white light that fall on the mirrors. Some will be quenched and some augment, and build up a long colored band, a continuous spectrum. Thus in figure 2, cut 12, two rays are shown in harmonic oscillation, the arrowheads at the end point in the same direction, and an illuminated band is seen at 12. The spectrum there- cut 13. Diffracting I^ight over edge of razor. fore is not as bright as the radiant, for so many waves are destroyed, the spectrum from the sun is not bright, it is easy on the eyes and beautiful. RADIANT ENERGY. 43 DIFFRACTION. In cut 13, the diffraction or breaking of light is shown where light from the lens is seen diverging to the screen, but half is cut off by he edge of a razor or sharp knife. When the primary wave hits the edge of the knife, a new set of waves is set up on the particles of metal, and they radiate light, some above and some below, as seen on the screen. One cir- cular wave front is shown moving away from one rough saw- tooth on the edge of the razor, and two in the original wave series. These and millions more interfere and break up the light, for diffraction is interference. If the light used is of one kind, as orange, black spaces and orange will appear on screen. If white light, the screen shows colored fringes in order of wave lengths. But the razor's edge corresponds to the eleva- tion of metal between two grooves shown in the vertical grating, cut 9, and in figure 7, loA. And all the inclined sides of the grooves correspond to the inclined mirrors, cut u. And this is the philosophy of the grating in the most primitive form, where if it were being treated mathematically, one-tenth of the space would be required that is taken by this multitude of words. Cut 10 shows four waves diffracted from the eleva- tions, all interfering on their wave fronts, and two coinciding in phase reflected from the sides of the depressions. This is the making of that priceless object, a spectrum. Refraction is seen in all its glory in the diamond, and ordi- narily in the prismatic pendants from chandeliers, gas fixtures, and lamps, and in cut glass. Diffraction is on display in the peacock's feathers, on the thin striae of shells, and on films of oil on water. They both cause interference and colors. Without them the earth and all things therein would lose their beauty. 44 RADIANT ENERGY. VI. ANALYSIS OF ENERGY BY MEANS OF THE SPEC- TRUM. "It appears to me that what we call the principle of heat is im- mortal that it knows all, sees all, hears all, both in the past and in the future. At the time when all was confusion the greater part of this principle rose to the circumference of the universe. It is this that the ancients have called ether." Hippocrates. All the preceding chapters have led to the projection of a brightly illuminated image of the slit on the grating. Energy falling on this thin band is worthy of attention of the highest type of intellect that has appeared. The slit and its resultant image are filled with countless quadrillions of waves, mixed in apparently hopeless confusion. To make use of the wonderful power of the grating, the image must be viewed with a telescope inclined to its surface. If not inclined, then dispersion of the energy into separate waves would not be seen and analysis could not be made. Each wave length must be examined by itself. And so small is the image of the slit and so narrow the spectral band that it must be magni- fied. Thus the one lens of the collimator forms 'an image with- out enlargement; the lenses of the telescope magnify. The result is a long belt of the most gorgeous colors from short-violet to long-red waves, and if white light enters the slit the spectrum is RAD I A N T E N ti R C Y. 45 continuous without break that is, every color between V and R is present. For if one tint-rate was missing, a black line an image of the slit would cross the band at right angles. This must be, for all the waves are separated by the rulings on the grating, and there are none to fill their places. This is a corner- stone in spectroscopy. Cut 14. This can be understood from cut 14, where the rough out- lines of a spectroscope are shown as seen by a person standing on a chair and looking straight down. A pencil of energy from the sun or any substance being analyzed by means of the energy it radiates, is seen reflected from the mirror through the slit and lens of the collimator and falling on the grating. The top edge of the grating is shown. It stands on a revolving table and can be turned through any angle as shown by the dotted lines. The edges of the table are ruled into 360 degrees and parts of a degree which are still closer read by vernier and microscope. The angle the grating makes with the incident ray can be meas- ured with accuracy. The elevations and depression on the grat- ing diffract break up and disperse separate all waves ac- cording to their lengths, sort them out by themselves and reflect them all upon the object-glass of the view telescope. 4 6 RADIANT ENERGY. The telescope turns in all directions around the center of the grating that is, about the image of the slit as a center, and these angles can be measured with precision. The angles of deviation are of great use, for finding by trigonometrical formulas, the lengths of the waves. These waves can be measured with ex- treme accuracy, the objective of the telescope renders the in- cident diverging rays parallel and projects the cylinder upon the fieldglass of the eye piece as shown. This lens makes the parallel rays converge and fall on the eye lens, which further converges and causes them to cross just in front of the lens in the eye, which projects an image of the spectrum on the retina as drawn ; but the observer thinks the image is far from the eye in space near the middle of the telescope shown in the dotted spectrum and the letters V I B G Y O R. The size of this imaginary spectrum depends on the angle made where the rays cross between the glass lens and lens in the eye. For the side of the retina marked A, sees red light in the direction R ; and the side of the retina marked R, sees violet light in the direction V, and it is a principle in optics that the observer imagines an object to be in the direction in which rays fall on the retina. If white light enters the slit, the eye will see all possible colors from R to V, but if any waves are missing, a black line will be seen, as in figure 2, cut 14, where all the blue waves, two red and one violet, are absent. All phases of matter, when hot enough for corpuscles to have room sufficient in which to oscillate at their own rate, pro- ject spectra consisting of bright lines only, no two phases being able to cast identical sets of lines. This is one of the chief facts known. Heat sodium, for instance, hot enough, either by a Bunsen burner, by the electric arc or spark, and hold it close to the slit, and the conditions rep- resented in cut 14, figure 3, will be seen. Two bright lines in the yellow flash out, and all other portions of the spectrum will be RADIANT EN ERG Y. tf black. This is because the metal sodium is unable to vibrate in more than two rates, and cannot set up any other waves, hence their places must be dark. So far, more than 80 conditions in which matter exists, have been found, and their bright lines care- fully measured and mapped. These lines and bands are the nat- ural alphabet. He who desires to know of the universe must read. There are 42,175 long" sodium waves and 43,078 short in one inch. The rate of the long waves is 495 million million, and of the short 507. million million oscillations per second. This is known to be true, and may be demonstrated by analysis, either of the energy, or the sodium as one pleases to call it. The Roentgen or X-rays are much more rapid. The metal sodium is the basis of common salt. The ocean spray is evaporated in the air, leaving minute particles of salt in suspension, filling the atmosphere around the globe. So deli- cate is spectrum analysis that it is almost impossible to be rid of the two yellow sodium lines, while making analysis of other metals. Bunsen found that the one 14-millionth of a milli- gram of sodium projected the. well-known yellow lines. The rustling of a paper or movement of the hand through the air arouses a hurricane of the particles, these fall into the source of heat, are instantly torn into corpuscles hundreds of millions of times smaller, and these set up waves that enter the slit. Lithium vibrates with two rates, one yellow and the other orange. Iron beats with about 480 different velocities, while the metal thallium has but one rate. IDENTIFYING THE LINES. Each line cast by any state of matter must be capable of being identified by inspection. The distances between the lines, the widths of the lines themselves, and their positions in the spectrum, are invariable for the same purity, temperature, pres- sure and grating. 4 S RADIANT ENERGY. Widths, spaces and positions are measured by means of a micrometer placed in the eye-piece. This is an instrument com- posed of two spider webs crossed like an X and stretched across a moveable frame in the field of view ; that is, they are in front of the spectrum and can be moved by rotating the screw so they will bisect any line or space and measure all with an accuracy almost past belief. It has been agreed to by spectroscopists throughout the world to adopt the universal standard of ten- millionths of a millimeter in which to express wave-lengths of radiant energy. The spicier lines must be illuminated by a side light to render them visible under all circumstances. For they are so thin that they are not at all times visible when in front of the colors of the spectrum. This is the office of the electric lantern, 2, 3, cut 8. Cut"15. Spectroscope in I^owe" Observatory. In cut 15, is shown the complete spectroscope in the Lowe observatory. The grating is shown between the objectives of the collimator and view telescope, while the micrometer is seen to the left, attached to the eye-piece of the telescope. The slit is at the right, and the edge of the circular ruled turntable is shown under the grating in the center. The entire instrument stands on RADIANT ENERGY. 49 three leveling screws to centre the slit on the mirror of the heliostat in the bright sunshine outside. The ruled screw-head is not seen in the cut, being on the opposite side of the tube ; but the window of the micrometer is seen on this side. The little tube attached to this side of the telescope is an electric lantern, in which is placed a minute (i c. p.) incandescent bulb with wires leading to a battery cell. When the current is on, the light passes to a right-angled or total reflection prism in the other end of the tube, where it is reflected through the win- dow pane shown, and strikes the webs in front of the eye. They look like minute fibers of glittering white and are clearly visible against any color behind them. Each spectroscope must be made the subject of experiment until the value of one turn of the screw is found in ten-millionths of a millimeter, and is called the constant of the micrometer. One millimeter is very nearly equal to the i-25th of an inch, and therefore it is with 25-millionths of an inch that the modern spectroscope deals. It is hoped that the word inch will disappear from scientific literature. When any phase of matter casts a spectrum, it is better to let its light make a graph on a sensitive plate than to make a map by hand drawing. The natural writing is more accurate, and the lines can be measured with a measuring machine as well as by the web micrometer. Thus photography, that majestic science, is the constant companion and helper of the spectroscopist and astronomer. In cut 15, the telescope and collimator are opened at a very wide angle to give a view of the grating, both objectives and the lantern. The spectroscope could not be used at so wide an angle; the telescope must be turned around. The slit is shown on the end of the collimator to the right. On the table below is a tube with lens in one end, which lens forms jo RADIANT ENERGY. % an image of any luminous object on the slit, so any part of the image may be examined instead of the whole object. This, then, is an analyzing spectroscope, where the slit with- out the lens between it and the object would be an integrating instrument. On the table to the left is a different kind of a slit from that of the collimater. It is for analysis of energy direct from the sun and will be treated in Part II, on astronomical spec- troscopy. RADIANT ENERGY. 5/ PART II. VII. ASTRONOMICAL SPECTROSCOPY. "Anaxagoras teaches that the ambient ether is of an igneous origin, and by the force of its gyratory motion it tears off blocks of stone, renders them incandescent, and transforms them into stars." Plutarch. The elementary notes I to VI inclusive, dealt with diffrac- tion, inflection, and dispersion of energy into a spectrum. Rates were from 395 to 764 million million per second commonly called light. It was shown that swings of corpuscles to and fro like a pendulum give rise to disturbances, which are imparted to the next and next and so on with a speed in a straight line always of 186,000 miles per second in space, and with less vel- ocity in transparent and refracting media. It was seen that white light is composed of an infinite nu Tiber of different rates of swing called colors, and that these vibrations could be sorted and placed by themselves by dispersing apparatus such as prisms and diffracting gratings. But when so separated it was found by a century of study that different phases in which matter exists could be detected by merely analysing the waves they set up. For each condition of matter when its corpuscles are vibrating at their own characteristic rates cause different sets of waves, varying in lengths, amplitudes and periods of oscillation. All of the eighty or more modes oi matter have been made to vibrate in front of the slit by heat, as from the electric arc between carbon terminals, in whose plus crater metals were placed, 5 2 RADIANT ENERGY. which were at once vaporized, forcing corpuscles to undulate in their own free paths ; or by the terrific heat of the stored up electric sparks through an air gap between terminals of metals under analysis and held before the slit. The current is passed through an induction coil, and if high potential is desired for the refractory metals, Leyden jars with air spaces are set up tandem in the secondary circuit of the coil, which turn the most obdurate metals to gas, and set the corpuscles into rapid pulsation, sending their own waves to slit, grating and spectrum. Also the heat of the oxy-hydrogen jets, gas jets, Bunsen jets, air and coal gas, as well as alcohol flames have been employed to set corpuscles swinging, the object of all being to get their energy in the spectral band into a state of isolation for exam- ination by themselves. The entire process is termed spectrum analysis, or spectrochemistry. But all this took place among familiar states of matter here on the earth. The whole three centuries of incessant work even if everv condition on the earth were analysed, would amount to little since the earth in space is smaller than one of Thomson's corpuscles in proportion to an ordinary room, and an "atom" of hydrogen the smallest physical body known, is 1,000 times more massive than the corpuscle. So if men could not enlarge their sphere of action and get away from this terrestrial sphere the entire labor of the human species from appearance here, would be exceeding small. Hence the whole subject of spectrochem- istry, with its extensive literature, with its record of arduous "oil day and night, with incessant vigil of the tiny electric spark and smaller wave, with its days and months and years of in- credible work and consummate skill of body and brain, the finest yet developed on the planet all these and all the books, whose titles only fill a large volume, all must be passed here and that other branch of spectroscopy taken up, the astronomical. So far bright lines only have been noticed, luminous as they RADIANT ENERGY. 53 fell in their regular places fresh from hot, vibratory corpuscles. But in 1814 Fraunhofer looked at the solar spectrum with a telescope and saw "an infinite number of vertical lines, darker than the rest of the spectrum, and some of them appear entirely black." He mapped 576. (See his map in Fig. 4.) He died without knowing their cause. In 1822 Brewster put colored glasses between the sources of light and the slit. The entire spectrum disappeared except the waves having the same color as the glass. Herschel did the same with colored glass and also with rok iv:l liquids. They quenched all waves except those they emitted. If white light be passed through red glass the whole spectrum vanishes except red. In making researches in absorption the physicist Brewster wrote : "The first object of my inquiries was to discover a general law of chemical analysis in which simple or compound bodies might be characterized by their action on different parts of the spectrum." He said there must be absorption, but this mighty law he failed to see in all its clearness to him it appeared in dim outline like a ship coming out of mist. The human mind was groping in darkness in presence of one of the chief mysteries of nature. This was in 1833. The black lines in the solar spectrum were absolutely inexplicable. Becquerel photographed these lines in 1842 and Draper in 1843. About this time bc^an one of the most extensive series of re- searches in the history of the world. Arduous and long con- tinued. Every physicist knew that a magnificent law was hidden in the black solar lines. PRODUCTION OF BLACK LINKS BY EXPERIMENT. Spectroscopists began to imitate the sun. Foucault in 1849 projected white light through yellow sodium light in an electric arc and produced two black lines in the exact places of the two 54 RADIANT ENERGY. yellow on a screen. For some reason this did not awaken the world, although it was the beginning of celestial chemistry. Men had to wait ten years until that eventful and auspicious day, Octo- ber 27, 1859, when KirchhofFs immortal work was read to the Academy in Berlin. Here are a few of his words : "I formed a solar spectrum by projection, and allowed the solar rays concerned, before they fell on the slit, to pass through a powerful salt flame. If the sunlight were sufficiently reduced, there appeared in place of the two dark lines, D, two bright lines ; if, on the other hand, its intensity surpassed a certain limit, the two dark lines, D, showed themselves in much greater distinctness than without the employment of the salt flame." These words have the same relation to spectroscopy of the sun and stars that the Constitution has to people of the United States. They are fundamental, historic, wonderful. The basic fact can be understood by means of Cut 16, where is shown a lamp burning alcohol which makes great heat with little light. The wick has been saturated with a solution of com- mon salt and dried. The heat volatilizes the metal sodium, tearing its particles away from their union with chlorine. They vibrate at their own rate, and fill the entire flame with dense yellow light. If now this light be passed through the slit, two brilliant yellow lines are seen at A, and the remainder of the spectrum is dark, because sodium is unable to vibrate in more than two rates. Cut 1 6, Fig. 2. If strong white light concentrated into a beam be sent, say from an electric arc, through the flame, the bright yellow lines vanish and all the other parts of the spectrum reappear, ex- cept in the two places occupied by the bright lines which are now black. Fig. 3. And if instead of the electric light, sunlight be sent through the yellow flame, the two black lines already in the yellow region of the solar spectrum become blacker than before, Fig. 4. RADIANT ENERGY. 55 WHITE SCREEN" Cut Id. Klectric Carbons, Alcohol Flame, and Absorption Spectra. 5 6 RADIANT B N B R G Y. If a piano wire tuned to say C, be stretched across the end of a long room, and many other wires all tuned to C be stretched somewhere near the other end of the room, with an observer standing behind them then if the one distant string be set in vi- bration the listener will not hear it, but will hear the C note in all the wires near him. The many wires cut the waves of the one other out of space, ami quench them by appropriating their energy to their own use. Sound any other wire near the one C wire, and the listener behind the screen of wires will hear any note whatever except C. The wires in the screen are unable to vibrate in any other rate than that required to sound C. So with the corpuscles of sodium they are tuned to yellow with two rates and cannot oscillate at any others. Hence the yellow flame lets every other color rate through without hindrance and absorbs the yellow, producing black on the screen A. In cut 1 6 the prism or grating is not drawn. Fig. I is a continuous spectrum as cast by the electric arc alone. Fig. 2 is that of sodium alone. Fig. 3, .that of the electric white light shining through sodium yellow light. Fig. 4 is a minute portion of the spectrum of the sun near the sodium lines, showing others. But the two sodium lines always seen black in the sun, fall in the exact places occupied by the two bright lines of sodium. LAW III. All modes of matter when vibrating at their own rates absorb the same waves they are able to generate. Kirchhoff. The mystery of the sun is not yet explained. RADIANT ENERGY. 57 VIII. ABSORPTION. "One nature delights in another; one nature overcomes another, one nature overrules another, and the whole of them are one.'' Book of Stone, Temple of Memphis, Archaic Egyptian, Synesius copy. The extinction of energy in space or its absorption and con- sequent disappearance in matter is a deep seated fact in Nature. The appropriation and selection of waves by matter and their eventual return to space constitute the life of the universe, the ebbing and flowing of cosmical tides. In treating of that minute fraction of the total and invariable quantity of energy, usually called light, it is well to recall that if matter quenches every light wave that penetrates below its surface, it is said to be jet black. A black object is seen merely from a small portion of the incident light reflected from its extreme outside inconceivably thin layer of particles. The processes taking place in the next layer de- stroys light so far as seeing it is concerned, and in the present state of science seems to be lost falling on some bodies ; but if the waves strike a growing plant they do work. They are said to be absorbed, and a green leaf absorbs all waves except the green, which are reflected, and a red rose absorbs all waves but red. Thus there is no color on earth all colors are in the light. Particular attention must be given to absorption in the spec- trum of any light whatever. The subject is a mighty one, for by 5$ RADIANT ENERGY. this means only can the key to read the letters of the universe be found. Every absorption letter is made up of short vertical black lines in the spectrum of either our own or the multitudes of other suns in measureless wastes of space that is, the stars (suns), are read by means of waves that are absent, waves that would have reached the earth as bright light had they not been cut out by some means, which is now the problem to be solved the capital problem so far solved by man. Cut 17. Six Spectra and Scale. In cut 17 an attempt is again made to clear up the question of absorption, or destruction of wave motion. In Fig. i the paper appears white because white light falls upon it and is reflected without change. That is, the waves are not separated, but are mixed in confusion, and a jumble of all possible waves appears white. In 2 there is shown a continuous spectrum, all colors from red to violet are present. (It is difficult to explain spectroscopy without diagrams in colors.) The cause of this is the waves have been separated by a prism or grating; for when waves are dis- persed colors appear, for each wave vibrates at its own speed, free from all others. In Fig. 3 blue is missing, black results, for &' i;jM!V RADIANT ENERGY. 59 no other waves can fill that space; none but blue have such re- frangibility and cannot be bent into that vacant region. Indigo and violet are refracted by a prism or diffracted by a grating too far to the left, and the other colors not far enough to fall where blue alone is able. In 4 violet and red are wanting and four waves of the green also. These attempted to pass through a gas that may have been invisible or transparent to all colors except green, or possibly they hit against a block of wood, both equally opaque. In 5 the entire spectrum has vanished, by their having en- deavored to pass through an absorbing medium as black glass, or through a great thickness of clear glass or of water. At all events they are absent and black appears. In 6 a crude spectrum of the sun is shown with a few black lines only out of over 8,000 known. Since the spectrum did not fall on a surface able to quench all the waves, for many appear, and since a number of black lines are seen, the solar rays have surely traversed a gas having power to select, quench or absorb all the missing undu- lations whose normal spaces are occupied by black. The mi- crometer cannot be well shown here, so a rule is drawn at the bottom of the series of 6 spectra. A straight edge placed on the 1 6 in the rule will coincide with the black line in the green rates in 4, and likewise with ruling No. 17. Evidently there is no mode of matter in the sun whose corpuscles swing with these rates or the waves have been counteracted between the sun and earth. For under all circumstances these two lines fall at 16 and 17 on the rule with the same prism or grating. Proof will be given in a note on solar chemistry that these states of matter really are incandescent in the sun and that the black lines are truly absorption spaces images of the slit black because these waves did not enter the narrow opening, being absent in those radiations reaching the earth from the sun, not sent, or, if emitted, absorbed. 60 RADIANT ENERGY. IMITATING THE SOLAR FURNACE. Ill cut 1 8 is seen an instantaneous photograph of two arc light carbons immediately after the current was shut off. The crater in the plus or lower carbon is still white hot, the cavity scooped Cut 18. Graph of Arc lyight Carbons. out by the flowjng electricity and its terrific heat, for carbon is the most difficult of all modes to melt or vaporize. Now, if the proper phase of substance is thrown into this crater and the re- sulting waves be passed through the slit, the two lines 16 and 17 in Fig. 6, in cut 17, can be exactly matched, if the two spectra are RADIANT ENERGY. 61 placed side by side that is, the lines will be end to end as in cut 16. This is the same as saying that the two black lines in the green corresponding will be filled with green light in Fig. 4, in cut 17. In the present state of spectroscopy part of the dark lines in the spectrum of the sun can be filled up with their proper light in the laboratory, but not all. There are black lines not yet accounted for that is, no mode of matter yet discovered on the Cut 19. I^ockyer's Klectric Arc and Projection Spectra. earth will set up the right waves to fall in these vacant places. At present a most exhaustive search is constantly being made to find phases that will oscillate at the solar rates and fill the lines with bright light. Modes have been found in the sun first, and afterward detected here on earth. These will be given in a note on the chemistry of the sun. Cut 19 is an outfit from Lockyers studies. In the left stands an electric lantern containing the two carbons in cut 18. 62 RADIANT ENERGY. Wires enter the bottom. To the right is a lens L. Next is a Bunsen burner burning city gas mixed with air coming in along- side of the gas below. The spectroscopist is holding a platinum spoon in the hot but dim flame high heat, low light ; the waves are too long for light. The heat is not great enough to melt the platinum, but will vaporize the less refractory metals. Place a piece of metal in the spoon ; when it oscillates fast enough the flame will be filled with its corpuscles and will be colored with the color that the metal is able to generate. The metal may have one rate, as thallium, or many ; but whatever rates it may have the prism P will separate them and project a spectrum on the screen S S. And the spectrum will present bright lines due to the metal. It will not be continuous. All parts of the band will be dark except where the thin strips of light images of the slit fall. Each mode of matter vaporized gives a different set of lines. Now, when the bright lines are on the screen turn on the white electric light from the lantern and pass it straight through the Bunsen flame. Instantly all bright lines on the screen turn black, and all black parts of the spectrum are filled with light, the Bunsen flame allows all waves to pass through except those rates due to the vaporized metal within. That is the law of Kirchhoff. Cut 20 is far better than this method of a flame in the open air. At the left is an apparatus for the production of hydrogen gas. Next is the electric lantern as in 19. Then comes an iron furnace with chimney above. A long iron tube passes directly through the furnace, and can be brought to a great heat. The tube has a glass window at each end. The air is expelled from the pipe, which is now filled with hydrogen to be rid of oxygen. Any metal whose point of vaporization is less than that of iron is put into the vertical tube up through the roof of the furnace as shown. The pieces of metal slide down into the tube and hydrogen. The fire is now lighted in RADIANT ENERGY. 6j the furnace and the metal is turned into a vibrating gas. Then the powerful white light from the electric lamp is passed lengthwise through the glass ends of the tube and falls into the slit of the spectroscope on the right for analysis. Absorption Cut 20. I,ockyer's Absorption Furnace and Spectroscope. bands and lines can be measured with the micrometer and re- corded. There are other more modern ways of studying absorption. And the absorption lines of all modes of matter so far discovered are tabulated. RADIANT ENERGY. IX. EXPLORATION OF THE UNIVERSE. "For consider, Purna, that great vault of space, the sun shines forth and there is light, the clouds gather and there is darkness, the winds arise." Kiounen Sutra, Chinese Scriptures. "But if darkness, light and sight be separate and independent, one of the other, then if you remove light and darkness, there is nothing left but void space." Buddhistic Sutra. In cut 21 are shown three of the most valuable instruments in the possession of scientific men three mighty engines for the conquest of nature. They explore the mysteries of the si- dereal universe, and reveal its secrets. Without a full knowledge of these three and how to use them, man must have forever re- mained ignorant of the vast cosmical structure in which he finds himself an inconceivably minute portion. The dust in the air in the room in which the reader may be is larger in proportion to the space in the room, than the earth is to space revealed by the telescope. The lenses shown bring energy into the slit of the spectro- scope from our own and countless suns besides, and from nebulae in the limitless sea of space, and projects the telltale waves upon the grating. This analyzes them and makes known the con- ditions of matter sending the tiny undulations. It becomes known what the structure of nature is composed of. And that other lever to pry up the universe, the differential and integral cal- culus, culminates the present achievement of the human brain. RADIANT ENERGY. 65 Once let its grasp seize the mechanism and motions of suns and solar systems or anything that can be chained to the servitude of mathematics and all is revealed. No motion can escape its searching analysis ; it drags forth the most abstruse and hid- Cut 21. Calculus, Lens and Grating; three, mighty engines for exploring the universe. den mysteries of matter in all its movements. Without these three, men today would be all unconscious of those majestic laws governing the sidereal structure. CHEMISTRY OF THE SUN. Having brought the separate parts of the modern spectro- scope together into a complete instrument, it is time now to use it, beginning with that fascinating work, the chemistry of the sun. The sun is 1,310,000 times larger than the earth, but the 66 RADIANT ENERGY. quantity of matter is only 333,426 times that contained in the earth. How the mass of the sun was found cannot be given in these primitive essays. With this volume and mass its density is only .26 or slightly more than one-fourth that of the earth. The sun sends out in stupendous floods in all directions, energy, solely in the form of waves. It sends forth 2,220,000,000 times more waves than are encountered by the earth. If waves interfere by odd multiples of half wave-lengths they destroy each other, or if they hit matter in these odd phases they destroy themselves, but if they strike matter in even phases they do an incredible amount of work. They sustain every activity on earth and alone keep up life. But men might have existed on earth until the sun is dead and would have been totally ignorant of its composition had not the spectroscope been studied out. Mass, volume and density do not give any indication of w r hat the mass is composed. The energy must be analyzed and waves to be ex- amined by themselves must be separated from all the others and this is done by prism or grating. COMPARISON. The comparison of energy from the sun with that of terres- trial substances when oscillating under the action of heat, is per- formed by passing waves from the sun and substance through the slit at the same time side by side. The bright lines from some phase of matter on earth will then fall end to end against dark absorption lines from the sun if there are any. This is shown in cut 22, where waves from some incan- descent metal is passed through the slit, and they will form a spetcrum. To the right of the slit at 5 in cut 15, and at 5 in cut 22 is a small right-angled prism, so that light entering a side is re- flected at right angles from the hypotenuse as shown in cut 22, RADIANT ENERGY. 67 REVERSAL IN THE SUN. Two arc light carbons are shown with a piece of metal in the crater of the positive. If the metal vibrates at 8 rates, then as soon as the current is turned on, figure I, cut 22, will be seen on the grating in the upper half of the slit. If now sunlight is pro- jected through the lower half, the grating will, show figure 2. There are 8 reversals, and the ends of both sets of lines coincide. It is at once inferred that the same metal is incandescent in both the sun and arc. The terminals of an induction coil may be substituted for the arc, in which case the heat of the disruptive discharge vapor- DIRECT SPECTRUM METAL SOLAR REVERSED SPECTfturt tARBGHS, COLUMAIOR. Cut 22. Light from Sun and Vaporized Metals compared. izes the metal, or low metals may be turned to gas in a Bunsen or alcohol flame. In all these cases, however, the differing sets of bright lines (one set for each metal) will come opposite a set of black lines, if the metal in question is reversed in the sun. These tests have been made by skilled spectroscopists in all parts of the world, and the results have been subjected to the mathematical theory of probabilities, when it is found that the chances of the metal existing in the sun are as three trillion to one. From the preceding notes it is known that black lines are caused by absorption; for take the metal out of the crater and 68 RADIANT ENERGY. place it in a Bunsen flame, between the arc and slit, as shown by the dotted lines in cut 19, then the white light of the arc will pass through the dim flame, all, except the eight rates, set up in the flame. Figure I will be filled with every color except the eight lines, which will now turn black. Thus absorption can be produced in the laboratory corresponding exactly with that taking place around the sun. It is clear, therefore, since selective absorption is produced by oscillating gases only, that there must be vi- brating gases between the sun and earth as well as between the arc and slit. These gases constitute that wonderful thing, the atmosphere of the sun. The air there is made up of gaseous metals. If there are other modes of matter in the sun, they are in a state of disso- ciation, so they cannot vibrate in rates that will form a spectrum at least in the visible portion or are obscured by the profusion of metallic vapors on the sun. Dissociation is Lockyer's theory, and seems to point to the conclusion that there exists but one kind of matter. The sun then contains the same kinds of metals at least that make up the metallic store on earth. And incredible quantities of hydrogen, and helium also. Professor Charles A. Young, General Astronomy,, p. 215, Revised Edition, says that the following elements are known to exist in the sun. Iron, Calcium, Magnesium, Erbium, Nickel, Ccandium, Sodium, Zinc, Titanium, Helium, , Silicon, Copper, Manganese, Neodymium, Hydrogen, Silver, Chromium, Lanthanum, Strontium, Germanium Cobalt, Yttrium, Barium, Glucinum, Carbon, Niobium, Aluminum, Tin, Vanadium, Molybdinum, Cadmium, Lead, Zirconium, Palladium, Rhodium, Potassium. RADIANT ENERGY. 6 9 There is yet a question as to the existence of oxygen in the sun, while chlorine, nitrogen, bromine, iodine, etc., appear to be missing or if present, hidden in a multitude of other incan- descent vapors. But the vast work has only started, for there are large num- bers of absorption lines not yet identified with matter on earth. The solar atmosphere is complex ; but not disconcerted, how- ever, with the great task, men are now attacking the problem with renewed energy. 7 o RADIANT ENERGY. X. SOLAR vSPECTROSCOPE. "As one sun illumines the whole world, so does the one spirit illumine the whole of matter. O ! Bharata." Hindu Bhagavad-Gita, Ch. XIII. Not only does the spectroscope reveal the constituent types of matter in the sun, but their conditions also. The sun is a mighty globe whose surface and regions above are in a state of excessive turbulence, upheaval and unrest. The most appalling explosions of pent-up gases, heated to temperatures far higher than known on earth, continually occur. Terrific cyclones and hur- ricanes rend the sea of incandescent vapors, and hot metallic winds blow with the most incredible fury. In the ninth paper it was shown how the spectroscope tells the composition of solar gases, by means of readings of absorption lines, the entire story being told by short thick and thin black lines. These and the adjacent colors are all that can be seen in a spectroscope as ordinarily ar- ranged in the laboratory. But the sun itself cannot be seen in this manner; for the mirror of the heliostat does not magnify, or if a lens is interposed between the mirror and slit it merely serves to make, a small image of the sun on slit plate. But now a giant lens must be placed between the sun and slit, and the heliostat removed. In short, the spectroscope must be transformed into a telespectroscope ; that is, be attached to the eye end of the great telescope in the dome of the observatory, the physical laboratory being closed. RADIANT BN ERG Y. 77 The new apparatus the telespectroscope, is shown in cut 23, where the spectroscope so far treated in these notes is seen fas- tened to the end of the sixteen-inch telescope, the extreme lower Cut 23. Telespectrograph in the L,owe Observatory. end of which appears. The great lenses are in the other end of the steel tube and are twenty-two feet higher in the top of the dome and pointed straight toward the sun. RADIANT ENERGY. Cut 24. Fig. 14 L,ens and Tube for Projecting Solar Image on Slit; Fig. 15. Slit for Solar Spectroscopy and Vernier. The slit for sun work is shown in cut 24, figure 15, where the slit is opened hundreds of times wider than when in use, for if narrow it would be invisible in cut. The movable arm and vernier upon which the figure 15 appears, slides around the ruled circum- ference and reads the position angle of any object that may be seen on the apparent edge of the sun. These angles are read from the North Pole of the sun and serve for future reference in making daily record of solar phenomena. It also rotates a tube behind the open slit. This tube contains a prism seen back down on the table to the left of the solar slit and circles, which makes the image of the sun appear to revolve around the axis of collima- tion of the telescope. Thus the entire periphery of the sun can be brought rapidly into view. The vertical brass bar containing the slit also has a vernier on the opposite side of the circular plate, by means of which the position of the slit on the edge of the sun can be read. The prism inverts everything. Looking through the slit and prism RADIANT ENERGY 73 at a distant house, the chimney appears all right, but if the cross- bar and tube with its prism be turned, the chimney will point to the center of the earth and to the sky, alternately. When the great object-glasses of the telescope are gazing at the sun they form an exceedingly brilliant image of the sun at their focal plane, at i, cut 23. This image is two inches in diameter, and the edge is allowed to fall on the narrow slit, now closed down to a width of i-ioooth of an inch. Cut '2ii. Images of Sun and Slits. This is made clear in cut 25, where a front view of the top of the slit end of the collimator, figure I, cut 23, is shown. In figure i, cut 25, the slit is tangental to the solar image, and in figure 2, radial, the light enters the slit and falls on the grating in the circular box at 2, cut 23. Here the light is diffracted into a long brilliant spectrum. It is the spectrum of the sun. It is reflected by the grating to the spectro-camera at 3. where it is graphed and filed away for future study and comparison with later graphs. Or by taking off the plateholder, an eye-piece can be attached for viewing solar explosions directly, for an eye (at the eyepiece) is liable at any time to see colossal explosions hurl- ing white hot matter to vast heights with terrific velocity. 74- R AD I ANT ENERGY. They are of all shapes and sizes, a few types being shown in cuts 26, 27 and 28. The lowest in any of the figures is 25,000 miles high and the highest shown is 145,000 miles. The three black dots Cut 2f>. Edge of Sun Showing Explosions. The Dot is the Earth's Exact Size. in 26, 27 and 28, represent the size of the earth in compar- ison. In cut 26 is seen a porion of the sun with six spots, and the small dot is also the size of our earth in proportion to the sun, explosions and spots. Sun spots have been measured whose area was 32 times that of a section of the earth, so 32 worlds like the earth could tumble in side by side with room to spare. The tele-spectroscope therefore renders the prominences visible and RADIANT ENERGY. 75 of Sun Showing Explosive Prominences, and Relative Size of the Earth. tells what they are made of when the telescope alone could not do either. The philosophy of enabling the eye to see the protuber- ances is that the grating displaces the mixed white light of the atmosphere of the earth. All know that the sky round about the sun is white, due to diffusion of light by dust and aqueous vapor in the air. But the spectroscope draws this white into a long band of colors, weakens the glow and intensity of radia- 7<5 BN BRGY. tion. This is because the light is white. But an explosion on the sun may be red, each set of waves being of the same length. They therefore cannot be dispersed farther; images of the slit of any object whose light enters it will be separated by wide dis- tances, but their brilliancy will not be lessened. An important result follows : They can be seen bright on a dim background. This is a great achievement in solar work, for before this dis- covery astronomers had to wait until a total eclipse of the sun EARTH Cut 27A. Explosions on Sun ; Also a Few Sun Spots in Comparison With the Earth. occurred. In that case, the moon cut off the sun, but left the prominences in view for a very short time. Thanks to Lockyer and Janssen, these wonderful objects on the sun can be seen in full daylight. In cut 25, figure i, the slit being on a tangent to the sun's image, happens to include three explosions. They can be either analyzed or photographed. Figure 2 shows slit radial, it is not wide enough to take in more than one upheaval. By rotating the arm 15 in cut 24 the entire circumference of the sun may be brought before the slit in a short time, and every outburst photographed. And men are making perpetual graphs of the sun, a continuous record for coming generations. RADIANT ENERGY. 77 285 Cut 28. Explosions on the Sun and Comparative Size of Our Earth. The sun cannot make an upheaval without being instantly photographed somewhere on the earth, the imperturbable eye of man is ever on the sun, for when it is setting at one place it is rising, or is at meridian altitude, at some other. The sun is now writing its own history, and it is a most interesting diary. It is thought that a graph taken now and one ten thousand years hence may show changes in the constitution of the solar mass, and that men by that time will have accurate knowledge concerning that stupendous star, the sun. 78 RADIANT ENERGY. XL SPECTROSCOPY OF THE SUN. "First the world was void, The first light was A urn ; Thence the alphabet. The seeds of the universe!" Primeval Aryan Literature, Hodgson's Trans. Royal Asiatic Society, II, 332. Since the continued existence of the human species on earth depends entirely on the radiant energy sent out by the sun, this splendid star must naturally be the subject of admiration and solicitude, now as well as in prehistoric times. The vast field of research and exploration has scarcely more than been entered. The combined energies of man must be centered on the hercu- lean work of taking energy out of space and chain it to his servitude. Men pay for power now ; it should be free. All problems so far presented to men for solution fall into insignificance in presence of the mighty problem of the ages how change the lengths of waves from the sun and make them fit for human use ? The question how the spectroscope makes the solar explosions visible is important and needs further study. In cut 29, figure i, is shown a slit filled with white light. In figure 2 is the same slit magnified. It is clear that if no additional quantity of light has entered, the band will be much weakened RADIANT ENERGY. 79 in brilliancy after being spread over so much greater area. And the prism or grating would spread it over the entire belt if the light were white, but not widen it at all if the slit contained red or blue or any other homogeneous waves. This is because white light contains waves of every degree of refrangibility capability of being bent aside and homogeneous light only one degree. This is the secret that renders prominences on the sun visible without an eclipse. VI B< i Y R V I B G Y Cut 2! I. Kig. 1, Slit. Fig. '2, Slit Magnified. Fig. 3, Slit with One 1 xplosioi in the Red Knd of the Solar Spectrum. Cut 29, figure 3, represents a wide slit, with the dim out- lines of an eruptive prominence on the edge of the sun, invisi- ble to the eye or to a low-power spectroscope, for the white light is as bright as whatever may be the color of the cast-up matter. In figure 4, the wide slit is magnified still wider by a high-power spectroscope, its white light widely dispersed and greatly weakened, while if the explosion is of any homogeneous color say red its light is not dispersed and is not fainter, it is visible against the dim spectrum, due to the dispersed white light as a background, and appears in the place of red. 8o RADIANT ENERGY. WIDE DISPERSION. The process of being rid of the white light diffused in the earth's atmosphere is shown in cut 30. The prismatic telespectroscope in cut 30, takes the place of the Lowe grating telespectroscope on the end of the great telescope, as shown in cut 23, Chapter X. Figure I, cut 30, is over the slit in the collimator tube, the screw for opening and closing Cut 30. Prismatic Telespectroscope. the slit being to the left of (i). The light from the edge of the sun comes through it and falls on the lower half of the first prism in the train. This disperses the light somewhat and projects it against the lower half of the next, and so on to the terminal prism, marked (2), upon whose hypotenuse falls the spectrum. This reflects it without change through the top half of the first prism, and on through the tops of all until it emerges from the last and enters the open tube (3) as a beautiful spectrum. It encounters a rectangular prism in the brass box (4), which re- flects it up to the eye-piece (5), through the micrometer (6). An eye placed at (5) may at any time during the day see an explosion as shown in cut 31, figure I, for instance, where quite a number of ordinary prominences are shown, giving no indica- tion of the mighty upheaval soon to occur. RADIANT ENERGY 81 Fio. 49. THE EARTH THE EARTH AS SEEN AT 8.30 P. M. 100,000 miles to tfie inch. Cut. 31. Solar Explosions; Figs. 1, 2, and 3 Show the Great Rapidity of These Turbulent Masses. Figure i is as seen by Professor Charles A. Young of Princeton, N. J., College, at 2:15 p. m., July 25, 1872. Figure 2 is at 2 145 p. m., 30 minutes later, and 3 is the same at 3 130, after an interval of 45 minutes. The scale is 100,000 miles to the inch, and the earth is shown in exact size to the left, just above the figure 2. The height of the explosion at 2 is 125,000 miles, the vertical ascent being 100,000 miles in 30 minutes. When it reached this altitude it seems to have been caught by 82 RADIANT ENERGY. a mighty wind of hot metallic vapor and bent over to the left at almost right angles. These outbursts are classed as "the quiescent, cloud-formed, or hydrogenous, and the eruptive, or metallic/' Young, Seechi, etc. The quiescent are composed mostly of the light gas hydro- gen, but the eruptive look like jets, spikes and projecting horns. They change form rapidly, and are made of such metals as mag- nesium, barium, sodium, iron and titanium and others at terrific heat. Several spikes and jets are shown in cut 31, and also the dimensions of the earth to the right of the jets. The highest prominence, accurately measured, reached a height of 309,000 miles. A. P. JL, October, 1901, page 213. The explosive promi- nences at times are so intensely brilliant that they can be seen on the disc of the sun far away from the edge, being much brighter than the solar surface, which in turn is many times brighter than the light of the most powerful electric arc yet produced. Their velocities of ascent range from 50, 75, 100, 150, .and a few have been measured with the incredible speed of 250 miles per second. AYith what terrific force they were shot forth from the sun. Per- haps at the instant of outburst the metals were in gaseous form so dense as to be almost liquid. Cyclones twist up white hot matter to great heights, and in some cases the tops of these expand into thin clouds and remain up for several days floating upon the upper layers of denser gases beneath. Professor W. W. Campbell of the Lick Observatory, in his lecture to the Southern California Academy of Sciences in Los Angeles, on March nth, 1902, presented a series of photographs showing that some of these outbursts are intimately related to sun spots. The mystery of the sun is the vast quantity of hydro- gen extending entirely around it in sheets or layers, and also being incessantly hurled forth from below the apparent surface with a force thousands of times greater than that of hissing steam from a high-pressure boiler. RADIANT BNBRGY. 83 In cut 30, figure 6, is shown that powerful instrument, the spectro-micrometer. It measures every object in the field of view with extreme accuracy. The screw carrying the wires is shown to the left, close to the 6. The value of one turn of this screw in seconds of arc must be found by astronomical methods. When this is determined the wires can be removed up so as to just include an explosion or spot between; then. the screw may be turned until both wires coincide and appear as one. The number of turns multiplied by the value of one turn in miles or kilometers, gives the height or diameter. The angular diameter of the sun is 1,924 seconds of arc; and its distance is 93,000,000 miles. From an elementary rule in trigonometry it is known that one second is 450 miles on the solar disc. If a prominence ex- tends to the height of five minutes, or 300 seconds, its altitude is 135,000 miles. Measures are recorded of all these that are worthy of record. But of all records yet devised, those made by the photograph are the most accurate. This leads to that high branch of research solar photography. 84- RADIANT ENERGY. XII. RADIANT ENERGY AND ITS FIXATION. O Thou of whom all is the manifestation, Thy nature is the spring of thy being: Whatever is, is thou ; We are all billows in the ocean of thy being; We are a small compass Of thy manifested nature From Dabistan, Vedantic Phil., Hindu. This paper might more properly be called radiant energy and its fixation. For now radiant and oscillating energy is to meet cessation, the waves are to do work on particles of silver, leave their records and come to rest. The sun must do writing and imprint graphs of its daily work, ceaseless turbulence and up- heaval. The water at the foot of Niagara is not more turbulent and not tossed and torn into more fantastic shapes than is the seething surface of the sun. But how shall these fleeting forms be photo- graphed, and by what possible means can an explosion hurling up white hot jets 40,000 miles wide and 200,000 high, with the terrific speed of 200 miles per second be instantly portrayed on a sensitive plate so as to appear at rest, like the spokes of the driving wheel of a locomotive moving a mile a minute ? And the heat will not the great heat of the sun destroy plates and pre- vent light from making record ? These were the problems that were encountered by astronomers from the year 1850. Not only must the prominences be made to record their forms, but spots, facul?e, granulations, filaments, solar clouds and corona had to be made to appear on the films; but of far more importance, the RADIANT ENERGY. 85 solar spectrum also was required to make imprint, or little could be learned of the constitution and structure of that majestic object the sun. And then came workers who knew no rest, whose labors were more arduous than those of Hugo's ''Toilers of the Sea." In a preceding paper a cut was inserted showing three colossal engines at work for the enlightenment of man, the cal- culus, lens and grating. To these must now be added a fourth, the gelatine bromide plate. It brought work, toil unknown in intensity outside an astronomical observatory. The sensitive plate now takes rank with the discoveries of the ages like the Copernican system, the laws of Kepler, the law of gravity, the invention of the telescope and spectroscope, the multiplex tele- graph, induced electricity, the dynamo, the wireless telegraph and telephone, Hertzian and Roentgen waves, the obscure radia- tions of the Curies, liquid hydrogen and slow but sure approach to the end, the absolute zero. Those who reared the pyramid of Sulphis, dug the Suez Canal, tunneled mountains, made ocean steamers, laid the Atlantic cable, bridged Niagara, laid the railways of the earth and set up the dynamo, did.no more remarkable work than the toilers who, from 1834 to 1902, wrought, day and night, to bring astronomical photography to its present high estate to the full- ness of majestic science. The plate is displacing men from the eye-end of the telescope, the human body, nerves, brain and eye, with all their forms of personal idiosyncrasy, imperfections, limitations and errors, must go ; the plate makes no mistake. Not less remarkable were researches on the application of photography to astronomy than were those so long and persistently made to find the cause of the Fraunhofer lines. The first attempt to photograph the sun, or rather its spec- trum, was made by Professor J. W. Draper, in 1834. He had merely a sheet of paper roughly coated with silver bromide. He 86 RADIANT ENERGY. failed, but the effort was a turning point in human advance. He took a small daguerreotype of the moon in 1840. M. Da- guerre having discovered his process on August 13, 1839. Dra- per, in 1842, and Becquerel, both made types of the moon, and in 1843, m ade a graph of a rough diffraction spectrum. Foucault and Fizeau, on April 2, 1845, actually produced a daguerreotype of the sun. Then came Bond, in the now historic Harvard College Observatory, and took graphs of the moon in 1850, and copies were exhibited in London on May 9th of that year. On July 17, 1850, Bond and Whipple took the first photo- graph of a star, the star Alpha Lyne. In 1851 Busch took the first graph of a solar eclipse. All these were daguerreotypes. Then came the collodion process, and De la Rue, in 1852, took graphs of the moon by means of wet plates. On June 9, 1854, Hartnup presented ten collodion graphs of the moon to the Royal Art Society in London. April 24, 1854, was a prophetic day, for Sir John Herschel recommended that daily photographs of sun spots be made. From 1857 to 1863 Professor Henry Draper made many collodion graphs, '1,500, of the moon, with ever increasing definition. In 1857, Bond, with more sensitive collodion plates, photographed stars, even to the sixth magnitude. He began a historic move- ment, for he measured the distances between the minute dots, the stellar images, giving rise to accurate determinations of star motions, if any are shown on later graphs. Rapid advance was made from 1857 to 1860 by many physicists, most notable of all being De la Rue, Bond and Pritchard. Rutherford began his great work in 1858, and made research on lenses and mirrors. July 18, 1860, is memorable, for De la Rue and Seechi both secured graphs of the total solar eclipse of that date in Spain, and proved that the prominences were actually on the sun and not an optical illusion on the edge of the moon, for the advancing edge of the moon covered and uncovered the scarlet jets and R.ADI ANT ENERGY., 87 heaps. On February 2/th and March 3d, Huggins obtained a graph of the spectrum of the star Sirius. It was not until 1865 that Rutherford discarded lenses corrected for visual waves and made objectives corrected for those waves only making the best action on salts of silver. This placed modern astronomical pho- tography on a strictly scientific basis. His graphs were marvels of definition and perfection. On November 28, 1870, that emi- nent American astronomer, Professor Charles A. Young, photo- graphed the prominences on the sun without an eclipse. In 1874 photography was used in recording the positions of the planet Venus in its transit across the solar disc. These positions are used to obtain the distance of the earth from the sun. All the graphs so far taken were on collodion plates. But now comes a most important improvement record breaking so it proved. DRY PLATES. That auspicious year, 1876, came, and with it gelatine dry plates sensitive enough for astronomical graphs. Immense impe- tus was at once given to graphic research, for these plates could be exposed for hours, on faint work, all night, in fact, if at work on stars and ncbulre. The gelatine film holds the particles of silver bromide in place so they will store the radiant energy of the universe. Now storage of energy is the highest achieve- ment of human hands. Huggins soon stored energy falling on the earth from the star Vega, and saw on his plate seven strong absorption lines. On July 20, 1877, Draper discovered oxygen in the sun, and from this time astrophysics made the most rapid progress since the primeval Aryans watched the stars from the uplands of Central Asia. Exceedingly rapid exposure is made for sun work, and extremely slo\v for faint star graphs. Photographs may be taken hourly of the prominences, as well as spots, faculae, or the entire disc. 88 RADIANT ENERGY. Cut 32. Solar Prominences ; Mainly Hydrogen ; Helium and Gaseous Metals Also. Cut 33. Spectra of Four Suns ; Alpha Orionis, Beta Pegasi, Alpha Lyn and Our Own Sun at the Bottom of Cut. RADIANT ENERGY. S 9 Cut 32 reveals a number of forms of solar explosions. Their height varies from 20,000 to 160,000 miles, the lowest shown being about three times the diameter of the earth in height. These gigantic outbursts are of a bright red, against a dull red back- Cut 34. Total Eclipse of Sun ; Showing Corona ; the Black Center is the Moon. ground in the spectroscope. Their composition is largely hydro- gen. Cut 33 shows spectra of four suns, Alpha Orionis, Beta Pegasi, Alpha Lyrae, and our own sun being at the bottom. QO RADIANT ENERGY. Cut 34 is that of a total eclipse, showing the black body of the moon in front of the sun, cutting off its light, allowing the explosive prominences to appear around the edges, with the great streamers of the corona far beyond. This photo was taken with- out a spectroscope, as no dispersion was required. Cut 35. Ordinary Laboratory Spectroscope. Cut 35 is that of an ordinary Browning spectroscope used in a laboratory for making analysis, and is not used in astronomical researches. RADIANT ENERGY. 9 i XIII. SOLAR SPECTROGRAPHY. "His radiance is undecaying." Rig Veda. "The royal sun feedeth all." Sophocles Oedipus Tyrranus 660. This has now become an important branch of work in a modern astrophysical observatory. The year 1877 was also auspicious, for Janssen rose up and photographed the sun with clearness of detail not reached before. His graphs were one foot in diameter, and displayed intricate tracery of the sun with sharp definition. Countless tops of promi- nences appeared on his plates, all over the solar disc, where before the sides only of the exploded masses on the limb of the sun were seen. His solargraphs show granulations, shaped like grains of rice, and a network of distorted forms of white hot matter below or round about. The solar surface is mottled and looks like the elevations and depressions of very coarse and rough blotting paper, as seen through a low power lens. Janssen says : "The forms generally have rounded contours, but some are rectilinear and others polygonal, and in the intervals of this network the rice-grains are distributed, the granules being half obliterated, drawn out and confused." Popular Astronomy, Vol. II, 312, H. C. Russell. The success of this intensely difficult work was reached by 92 RADIANT ENERGY. reducing the time of exposure of the sensitive plate to the i-37. Total Solar Eclipse, Showing Lower Portion of Corona. sides of the sun and saw that the tufts and streamers on the east side of the sun were moving toward the earth, while those on the west side were receding. But the sun also revolves from west to east. Cut 37 is a total solar eclipse of sun showing matter hurled up on the edge of disc. 9 6 RADIANT UN HRGY. Cut 38. Trouvelot's Total Solar Eclipse ; July 29, 1878. Cut 38 is the magnificent drawing made by Trouvelot of the great corona of the total eclipse of July 29, 1878, made at Creston. Wyoming. The polar streamers and equatorial extensions are shown in detail, also the glorious corona of the sun. RADIANT ENERGY. 97 XIV. SPECTRUM ANALYSIS OF THE SUN. "In the beginning there arose the source of golden light." Rig Veda, Ch. 10-121, B. C. 1500, Aryan Scriptures. "From darkness lead me to light." From "Brihad Upanishad," Hindu Philosophical Poem. Elaborate study of the sun's surrounding can only be made at times of complete eclipse. The light and heat from the disc are so intense that close examination of the photosphere and corona cannot be made until the welcome moon comes along and cuts out the sun, leaving the external banks and clouds of incandescent gases in plain view. It must be ail occasion of wonder and sur- prise to many to see the civilized nations of the world, as well as universities and observatories send costly eclipse expeditions to remote parts of the earth to watch the extinction of the sun, which they know can last but a few minutes. In cut 39 is shown the path of the eclipse of January 21, 1898. The black line from Africa through India to Eastern Siberia is the path of total obscuration of the sun. Any astron- omer to see the splendid and impressive spectacle must be within this track. The widest possible shadow is 167 miles, but usually the width is much less. The mechanism of the solar system is known with such accuracy that the exact places on the earth where the eclipse will be total is computed years beforehand. So, RADIANT ENERGY. each Government knows precisely where to send observing parties. Sometimes astronomers pay their own expenses, and at others, some generous patron of science foots the bill. Many parties went to India in 1898 and the obesrvations were so successful that this eclipse is selected for explanation here. Among the triumphs of the spectroscope is its invaluable Cut 39. Path of Solar Eclipse, Jan. 21, 1898. determinations of the constitution of the gases round about the sun which cannot be studied in a telescope alone. This is be- cause no telescope can analyze light. At the instant of totality every telespectroscope is set on the sun and rapid photographs are taken. Plates are exposed and changed in the spectographs by hands trained by days of practice and drill, so that the human frame becomes an instrument of mechanical precision. To each observer is assigned a definite thing to do at a certain absolute moment of time. None of these can take their eyes from their RADIANT ENERGY. 99 spectrographs, telescopes, polariscopes, etc., so a man is stationed at a chonometer to announce the fleeting seconds. When he calls the time, each human machine moves in a carefully prepared pro- gramme. Since the invention of that wonder of the ages, the dry plate, and the rise of that vast science, spectro-photography, expeditions are sent to the ends 1 of the earth to secure per- manent records that is, photographs of all phenomena seen at Cut 40. Professor Campbell's Eclipse Outfit, Jeur, India. the eclipse, as shown in the telespectroscope. This is an instru- ment of great power attached to the telescope, whose objective collects the light emanating from gases near the sun and projects them into the spectrograph. This analyzes the waves, sorts them out according to their rates and lengths, and spreads them upon the plate, to make graphs to be stored for coming generations. Complete records are thus made of every eclipse, unless obscured by clouds. /oo RADIANT ENERGY. The graphs of the Indian eclipse were the best ever se- cured to that time. Everybody went armed with the best instru- ments known to science. It was agreed to obtain the best nega- tives possible of the corona and prominences, but above all to record the "flash spectra" of both contacts. Many parties went to India. The Lick Observatory sent an expedition under the direc- tion of Professor W. W. Campbell, and cut 40 is his station at Jeur. The great inclined tube is a telescope of forty feet focal length. Its lower or photographic end is lowered into a pit eight feet deep, where the object glass above projects an image of the sun five inches in diameter on the sensitive plate, in its focal plane. Nothing can exceed the skill required to mount all these instruments, before the day of the eclipse, with such accuracy that the sun will come exactly in front of the ob- jective at the supreme moment. After the momentous event Pro- fessor Campbell sent this telegram to the Lick Observatory: "The most satisfactory photographs of the corona were ob- tained with the three different telescopes. One set with a tele- scope forty feet long, and two other sets with five-foot and three- foot telescopes. The great equatorial extensions of the corona, which formed such a conspicuous feature of the eclipse of Jan- uary, 1889, has again been photographed. Also satisfactorily photographed the changes in the solar spectrum at the sun's edge with the aid of one of the spectroscopes." Professor Burckhalter, of the Chabot Observatory, was also present with the Pearson telescope. THE IXASH SPECTRUM. The most consummate skill is required to secure a spectrum of the reversing layer. The highest type of the genius of man is on display here. He must have every instrument ready and RADIANT ENERGY. wi every adjustment made with accuracy before the critical time. The flash spectrum must be secured within two seconds, or the journey of 10,000 miles will prove a failure. Photographing the flash spectrum is one of the chief results of modern research on the sun, and should be understood. The true surface of the sun is doubtless invisible from the earth. Its condition is un- known, but, since the entire sun is only 41 per cent more dense than water, the density must be greater at the center and least at the surface. The sun is in all probability made of liquid gas due to its own pressure. This may sound anomalous, but compress hydrogen under a piston to say one-fiftieth its normal volume, remove the pressure the gas will expand and the piston rise. The sun is not a permanent liquid, like water, and if solar gravity could be removed the sun would expand to planetary distances no doubt. It is inferred that the sun's surface is a liquid gas of low density, in a state of terrific heat and intense brilliancy. Above this, entirely around the sun, is a deep layer, or envelope, the photosphere, and this is what is seen in the telescope. THE CARBON PHOTOSPHERE. Recent researches have led to astounding conclusions as to its composition. Perhaps the concept of Sir Robert Ball is the absolute truth on this important subject; for man lives only by radiance from the photosphere. It is now known that carbon exists in the sun. This, in solid form on earth, appears in diamonds, charcoal, coal and coke, and is the most difficult of all known substances to melt or make liquid. Its specific gravity in gas or in finely divided particles, as in smoke, is low. It easily rises through the earth's atmosphere against gravity. The appalling heat of the sun is able to turn even refractory carbon to liquid, and then to gas. Its gas will rise through the dense I02 RADIANT BNHRGY. metallic vapors surrounding the sun into cooler regions, condense into liquid drops, or possibly into solid diamonds, and fall and collide near the solar surface. The collisions form the photo- sphere, therefore the photosphere of the sun is literally a colossal storm of rain and hail of liquid and semi-solid diamonds. Diamonds are not stones they are chemically pure carbon, and will unite with oxygen without residue. And this is the lat- est conception of that marvelous thing the photosphere of the sun. Metals allowed to resist electricity are instantly vaporized, and the reason why carbon is used in arc lights and incandescent bulbs is because it does not liquify. The brain cannot conceive the brilliancy of the white-hot carbon rain in the sun's photosphere, nor imagine the degree of heat. Other refractory substances, as silicon and perhaps some metals, rise in gas, condense and fall ; but none fall back so far as carbon where they are again turned to vapor, so the layer nearest the actual solar surface is pure carbon a thick shell of liquid diamond, with here and there a white-hot semi-solid gem. But above this, entirely around the sun are piled up colossal heaps and tumbling clouds of cooler gases, the chromosphere. What follows ? From Kirchhoff's first law (second paper) ; "All solids, liquids and gases under great pressure project continuous spec- tra." The spectrum of the photosphere is continuous. By Law III, (eighth paper), "All modes of matter when vibrating at their own rates absorb the same waves they emit." Thus the cooler layers of gases above the carbon envelope, yet hot enough to vibrate at their own rate, absorb, quench and destroy the motion of all waves sent up from below, and these cannot reach the earth. All waves so destroyed leave empty places in the spec- trum, which black spaces are the Fraunhofer lines. If now the moon crosses a straight line joining the centers of the earth and sun, at such a distance, from the earth as to RADIANT ENERGY. 103 "fit" the sun, the entire disc will be" cut out, leaving the carbon layer, the chromosphere or the layer of permanent gases above it, together with all other clouds and layers, and, lastly, the corona in plain sight for the few minutes of total eclipse. Within two seconds before the exact instant of totality the following side of the moon, just going before the sun's disc, will cover, and two seconds later the advancing side will also cover the carbon ring around the sun, cutting off its brilliant light. What happens from the laws of Kirchhoff? The reversing layer that caused the Fraunhofer dark lines will now emit bright lines of its own, and these bright lines flash out with great brilliancy through the whole length of the spectrum and the glorious sight will be on dis- play two seconds or until the edge of the moon covers this layer also and cuts off the brilliant scene. This is the flash spectrum, and a spectroscopist will journey to the ends of the earth to see it. The flashing spectrum was first seen by Professor Charles A. Young at the total eclipse of the sun in Spain on December 22, 1870. When the moon had almost hidden the sun, the black lines were still visible, but at the exact moment of second contact, when totality occurred, he saw the usual black line solar spectrum disappear when : "All at once, as suddenly as a bursting rocket shoots out its stars, the whole field of view was filled with bright lines, more numerous than one could count." Young. Therefore, KirchhofFs law was actually proven to act on the sun as well as in the same experiment in terrestrial spectroscopic laboratories. The flash has been seen at subsequent eclipses and lines mapped. Cut 41 is the wonderful flash spectrum secured by Mr. "J. Evershed, at Talni, India. What height of human skill and trained work was required to take this photograph at once the carbon ring was covered and before the rapid moon had time to encroach upon the reversing 104. RADIANT ENERGY. Cut 41. Flash and Cusp Spectra Compared. Ultra-Violet Region I, 4100 to I, 3350. Enlarged Four Times From Negatives Nos. 3 and 1. layer above ! Thus Mr. Evershed had four complex instruments before him, all having to be manipulated with extreme accuracy ; yet he secured thirteen photographs in one and one-half min- utes. The nervous strain is severe, but the body is an abject slave to will. Cut 41 is Evershed's spectra, the lower being the ordinary spectrum an instant before totality, while the upper is the flash or reverse spectrum caught on the rapid plate one 1 half second later. All the black lines in the spectrum below are reversed, changed to bright above. They coincide end to end they are direct lines from the gases of the chromosphere. These lines are from" glowing iron, hydrogen, calcium, magnesium, helium, titanium, possibly silicon and carbon, with others ; in all, fifteen modes had their lines changed in this memorable flash. It will be seen how intimate is the association of iron and hydro- gen in the solar gases ; a great fact that will be noted under the head of cosmical and stellar evolution, later. RADIANT ENERGY. 105 Cut 42. Thwait's Graphs of Solar Eclipse. Exposure Upper 1% Sec., Lower 9 Sec. at Talni, India. Jan. 22, 1898. Cut 42 is that of two photographs of the eclipsed sun and its corona, secured by Mr. Thwait, at the same time. The upper is an exposure of one and one-half seconds, the lower nine sec- onds, showing much greater extension of that mysterious crown, the crown of the sun. io6 RADIANT ENERGY. XV. MALE'S SPECTROHELIOGRAPH. "He plants the eye of Surya in the sky, and disperses the delusion of darkness." Rig Veda, V. 40. "Bright-haired, white-footed steeds draw him along his ancient path without dust, and built secure, the golden-handed bounteous sun." Rig Veda. (Primeval Aryan). This remarkable instrument devised by Professor George E. Hale, now of the Yerkes Observatory, takes accurate graphs of the finer details of the apparent surface of the sun. Not only these, but the photosphere, chromosphere and the prominences can be graphed on any clear day without waiting for a total solar eclipse. This invaluable apparatus takes the place of an eclipse for all purposes, except graphing the corona. Knowledge of the sun was greatly augmented by the invention of this method of solar work and the thanks of the astronomers of the earth have already been rendered to Professor Hale. Its principles ought to be understood by all who admire the sun. Cut 43 is a graph of the heliograph as it appeared in Ken- wood Astrophysical Observatory in Chicago, before Professor Hale went to the Yerkes Observatory at Williams Bay, Wiscon- sin. It is attached to the lower end of a twelve-inch equatorial telescope, the same as the telespectroscope on the eye end of the Lowe telescope (Tenth Paper, cut 23). The entire disc of the RADIANT ENERGY. 207 sun is cut off before the slit by a circular plate of metal, taking the place of the moon at eclipses. The plate is just large enough to fit or cut out the sun and its photosphere, leaving the chromo- sphere alone and the explosions entirely around the circumfer- ence in plain sight. And Hale, by a most ingenious arrangement of double slits, photographs them all at the same time ; then he removes the metal plate and photographs the sun to fill up the Cut 43. Hales Spectroheliograph. circle, thus securing records daily of all phenomena that may appear on the disc, and in the surroundings except the corona. He has taken many hundred graphs. These fill the minds of solar physicists with awe and wonder at the complexity of the sun. The sun's photograph after the iron plate or screen is re- moved, is not taken at once, but is built up by successive narrow strips of photograph secured through a movable slit that slides w8 RADIANT ENERGY. across the image of the sun. The effect is as though a complete graph of the sun could be taken at one instantaneous exposure, for not only is the disc shown with minute details, but the chromo- sphere and explosive prominences. In cut 43 the first slit is seen at I, where it may be placed radially or tangen tally to the solar image as shown in Chapter X, cut 25. This slit in the Kenwood heliograph is 3*4 inches in length, and its width can be varied. It is mounted on steel balls so it can be moved easily across the image of the sun, in the plane of dispersion due to the grating. The light from the sun passes through the slit at figure i, falls on the grating in its box at 3, is dispersed into a spectrum and reflected to the slit, just under the sensitive plate in its holder at figure 2. The slits at figures I and 2 move in opposite directions, with the almost incredible effect of building up a photograph. In graph- ing faculse the slit upon which the solar image falls is i~5ooth of an inch wide. This slit moves at right angles across the image just below figure I say to the left; then the slit just below the plate-holder at figure 2 moves to the right, the only light falling on the plate at any one instant of time being a thin line, an image of the slit. To make the motions of both slits coincide in exact time, both slit plates are moved by the same power which is due to water coming in from a pressure through the rubber tubes (4, 4). One pipe leads to the top of a cylinder (5), which con- tains a piston actuating both slit-holders, Since the same pressure of water moves both slits, the motion is synchronous, and the solar image is graphed with equal exposure for each minute portion. Hence a homogeneous graph is made, and these graphs have elicited the admiration of all scientific men. The arrangement here described is for graphing the disc with its faculse and spots ; but if the prominences and chromo- sphere only are to be taken, a circular disc of iron just large enough to fit the two-inch image of the sun is placed about where RADIANT ENERGY. 109 the figure i appears. This cuts out the solar image as formed by light coming through the end of the telescope at figure 6. Hale's spectro-heliograph is as record making in modern astrophysics as J. J. Thomson's discovery of corpuscles is to electricity and to the universe, and as Ramsay's slow but sure approach to the absolutely zero of temperature, is to the root and foundation of nature. Clearly in the lead of all are his exquisite graphs of the faculse, objects scarcely visible in the telescope without the helio- graphic attachment. These are inconceivably hot figures, ar- ranged like blazing torches over the mighty disc of the sun. Their brilliancy is far more intense than in adjacent regions. When all is ready with the apparatus, graphs are secured at the rate of one per minute, where before it required an hour to get a poor imprint of the sun. Evanescent, fleeting and transitory objects, explosions, currents, cyclones and hurricanes are at once caught in their impetuous turbulence and appalling fury, and instantly brought to a state of rest, like instantaneous graphs of a cataract where the troubled water seems to be without motion. A complete history of an explosion 40,000 miles wide and 200,000 high is written by its own light. White-hot masses many times larger than the earth are hurled to these heights with speeds ranging from 50 to 200 miles per second. Up and up rises the awful, seething mass, but every move is photographed. There are now many heliographs in Europe, notably at Meudon and Potsdam, so that almost continuous records of the sun are written on permanent plates, especially since the graphic observatories in Sydney, Australia, have joined in the relentless conquest now on, the conquest of the mysteries of the sun. Professor Charles A. Young saw the calcium lines in solar faculae reversed in 1872. Hale now graphs them without diffi- culty. The H and K Fraunhofer lines, due to calcium at terrific heat, are reversed ; that is, they become bright. And the inevit- no RADIANT ENERGY. able hydrogen also appears. But reversal implies a force at work utterly beyond the brain of man to comprehend. The faculse are so incredibly hot that if there are cooler gases above they are powerless to absorb the fierce light and thus cause a Fraun- hofer dark line ; or else the hot material is hurled up entirely through all inclosing layers, in the nature of white prominences, at such unheard-of heat that their corpuscles cannot vibrate at their own rate too hot for that so give the well-known continu- ous spectra due to all white light. But they are made of calcium, a leading constituent making up the geologic structure of the earth. Young at first saw reversal of the lines merely, at or but slightly removed from spots. But Hale saw reversed lines on the disc far away from the penumbra of the spots. He conceived the idea because the reversed lines were so brilliant, even against the effulgence of the background of the sun's disc, that if this glare could be lessened the forms of the faculae could be appar- ently isolated and graphed. This he actually accomplished with his narrow and synchronously moving slits and rapid plates. The now historic day arrived, January 12, 1892 Hale photographed the brilliant faculse on the sun. These colossal areas of solar upheaval are now graphed at all hours of clear days with little effort. The most noteworthy thing about faculse, aside from their excessive brightness, is their enormous size. Spots large enough to take in thirty worlds like the earth were formerly thought to be large, but the "boiling-places," those seething cauldrons of the sun, are many times larger in area than the largest spots, and they show at all parts of the solar disc, while spots are mostly in equatorial regions. Human ingenuity seems to have reached its limit here, for the chromosphere and prominences on the edge of the sun are less brilliant than the hotter faculse, and therefore require a longer exposure. RADIANT ENERGY. in The circular plate of iron is held at figure I to cut out the sun, when the slit plates are both driven by the water with slow motion, giving long time exposure, going one way across the image. The iron disc is then removed, the sun's image again falls on slit plate, water flow is increased and the slits are moved Cut 44. Photograph Made With the Spectroheliograph of the Kenwood Astro-Physical Observatory, Chicago, by Geo. K- Hale, Chromosphere and Prominences. May. 24, 1892. with greater speed in the opposite direction across the field of view, giving short exposure, and this catches the faculae and graphs them all in their true places. The entire sun, together with all phenomena, are thus portrayed a thing thought impos- sible before Hale came into the intellectual arena of the world. These famous graphs are imperfectly represented in cuts IIP. RADIANT ENERGY. Cut 45. Male's Heliograph Showing White Hot Faculse. Cut -40. Kale's Snapshot of Solar Prominence. March 24, 1892. RADIANT ENERGY. u 3 44 and 45. Cut 44 (large circle of sun) is where the slits make their first excursion across, with long exposure several seconds with the iron plate in place of the moon at eclipse ; the chromo- sphere and a few prominences appearing. Cut 45 is Hale's photo- graph of the sun showing several white hot faculse, and three or four prominences on edge. Cut 46 is a snapshot of an explosion on the sun. Nearly all the wonderful details of the sun, as seen on the original negatives, are lost when transferred to paper. Cut 47. Male's Photograph of Solar Prominences, Showing Rapid Changes. Nov. 15, 1892. Cut 47 is a series of photographs taken November 15, 1892. Intervals between graphs i and 2, five minutes ; 2 and 3, twenty- five minutes; 3 and 4, fourteen minutes; 4 and 5, one minute; 5 and 6, two minutes, showing rapidity of changes in prominences. He also made a most remarkable composite drawing from four original plates. They were projected on a white screen by a I 1 4- RADIANT ENERGY. Cut 48. Kale's Composite Oraph of the Sun. lantern, thin paper being placed over the image and traced with a crayon. The four pictures are thus superposed. Two of the negatives showing prominences were taken at 9:15 and 9:59 a. m., and two showing faculse were exposed at 9 and 9 :o6 a. m. Hale placed a blue glass in front of the slit to absorb some of the light of the photosphere, thus making the faculse more distinct. Here is a quotation from Professor Hale: "I have else- where remarked on the great size and extent of the faculse as shown on photographs taken with the spectroheliograph. The negatives made with the blue glass absorbent, however, show that my estimates have been too small. Faculae hitherto invisible are now seen dotting the surface of the sun from pole to pole. The faint faculse do not appear to be separate and independent phe- RADIANT ENERGY. n 5 nomena; for over the whole surface of the sun they seem to be connected like the meshes of a net, though the forms of the inclosed spaces are very irregular." It is hoped that some of the marvelous network can be seen when cut 48 is transferred to the printed sheet. And now a ceaseless record of the sun is being made in countless heliograms throughout the world. n6 RADIANT ENERGY. XVI. SOLAR SPOTS. "The sun rises out of life and sets into life." Brihad Upanishad, vi-2 (Hindu). "The light of the sun is the soul that moves or rests." Rig Veda. B. C. 1500 Aryan. "Thou in the form of sunbeams, preserves! the world." Vishnu Purana (Hindu B. C. 800). "The sun sinks in the ocean, and azure-hued vapors arise ; it is Nature's incense of devotion perfuming the skies." Anwari Palinodia, Persian Scriptures. These have been watched with ever-increasing interest since the invention of solar eye-pieces for telescopes and with renewed activity since the appearance of the solar spectroscope and spectro- heliograph. They are periodic. The average period obtained from many years' observation is eleven years and two months. Sometimes it is near thirteen, and at others near ten years. The maxima occurred in 1848, '60, '70, '81, '92 and another is due in 1903. This period of eleven years and two months is composed of two unequal parts ; there are on an average six years between max- ima and minima, and five years from minima to maxima, thus the period of increase is shorter than decrease. Angot, Aurora, page 94. RADIANT ENERGY. nj A normal spot is composed of the dark umbra in the center and this is surrounded by the penumbra, somewhat lighter col- ored and in the center of the black umbra still blacker dots are seen called nucleolL With high-power telescopes the umbra is at times seen covered with filmy vapors, apparently floating over from the photosphere. A majority of spots are, however, so ir- regular in shape that they are not the typical form. The umbra looks black in the telescope, but Langley compared the light from the nucleus with the surface of liquid Bessemer steel in a blast furnace, and found that the black center of a sun spot is brighter than a calcium light, and its blackness is due only to contrast. Astrophysicists are now nearly all agreed that spots are depres- sions in the photosphere, filled with cooler and therefore heavier gases. And when they pass the edge of the disc, owing to rota- tion of sun, they are seen at times to be deep enough to cut out a notch. The penumbra is composed of long, separate filaments or streams of intensely hot matter from the adjacent photosphere, pouring over like a gigantic cataract. This process in time usually fills or submerges the spot. They are not deep, ranging from 500 to 2,500 miles, seldom so deep as the latter. Minute spots are in diameter from 500 to T,OOO miles, while others are seen almost daily, at maxima, in diameter from 40,000 to 60,000 miles. At times the penumbra has been measured, showing width of 150,000 miles. The actual beginning of a spot is rarely seen ; they com- mence in a minute black speck and rapidly expand. The penum- bra does not appear until the umbra is complete. If the spot is caused by an upheaval it breaks into separate fragments, all of which keep up with the turning of the sun on its axis. When a spot is about to come to an end, a jet or tongue of white hot matter, usually the end of a facula, starts to cross the fearful chasm. These are termed bridges. They rapidly grow wider, J -i_I : 'SRK'W ^ ^W* v" -; .e f. ^J,t * -. 2 > * <& . : Cut 49. Sun Spot, Showing Changes at 1, 2, 3 and 4. 5 is a Spot and Facula on Western I,imb and 6 on the IJastern. RADIANT ENERGY. ng others start, and then there is a continual flood of hot material from the photosphere, and this bends or pours down the penum- bra to the yawning umbra, and the spot vanishes, an exceed- ingly brilliant facula taking its place. Cut 49, figure i, is a twisting spot drawn by an observer February n, 1892, at the last maximum. Figure 2, is Feb- ruary 1 2th, 3, 1 3th, and 4, the I4th. Cyclonic motion, bridges, filaments and jets are well seen. The sun turns from west to east, opposite to the motion of the hands of a watch. Figure 6, cut 41, is a large spot coming on east, and figure 5 is the same spot going off west after an interval of 12 3-4 days if the spot is somewhere near the equator. For the equator revolves in less time than the surface of the sun in either latitude. Thus by watching a spot in latitude 45 degrees the spot will require 12.63 days to cross, that is, the sun revolves in 25^ days at the equator and 27^4 clays in latitude 45 degrees. The sun is not solid, there- fore, for all parts of a solid globe revolve in the same time. The cause of variations in solar rotation is not known, but vast currents in the equatorial regions seem a plausible theory, these flowing east, or currents in both latitudes flow west. The spots in figures 5 and 6, cut 49, are surrounded by the outlines of immense faculse. Some spots appear and vanish in a few hours ; others in a few days. Many make one or two cir- cuits with the sun, and one was seen to make 18 revolutions be- fore the faculse and torrents from the photosphere finally con- quered. Spots are confined to two zones 35 degrees wide be- tween 5 and 40 degrees in either north or south latitude. None have been seen near the poles, while faculse are shown in Male's graphs near both poles. The corona also stands out from both solar poles. In cut 50, a spot coming to an end is shown, with many bridges starting across in all directions, while cut 51 is a new spot, with only one jet starting in the lower portion. The 120 RADIANT ENERGY. -'.* frt- %; ? Cut 50. Sun .Spot Coming to an Kiid. Bridge Crossing Umbra. 3 % .' 1 ' Cut 51. Sun Spot Just Formed. No Bridges. ENERGY. 121 dots on each cut, 50-51, are true dimensions of the earth. Veiled spots are seen, large submerged areas, covered by thin cloud-like forms, as though they could not appear clearly through them, and these are usually enclosed round about by white-hot seething faculre. One at the telescope, viewing an active spot, can- not actually see the jets move, any more than the motion of the hour hand of a clock, but going away and returning in a half hour, the rotary displacement is noticed at once, or straight line ad- vance, if a bridge or jet is on the way across. Many theories have been given to explain solar spots or de- pressions, but none are free from objection. Faye thinks they are terrific cyclones twisting up matter like a waterspout at sea ; this cools, falls back denser and shuts out light from below. Secchi maintains that violent explosions occur around the place where a spot is to appear, drawing vast quantities of mat- ter laterally, and allowing the undisturbed portion near the center to sink into the cavity, and then the portions hurled up, fall into this depression, cooler from their journey of a hundred thousand miles or more. Professor Charles A. Young, an authority on solar matters, advocates this hypothesis. At first, the "motion of the center of a spot is inward not out- ward." (Young.) This is known, for the spectroscope at once re- veals whether a source of light is advancing or receding. The spot spectrum shows the solar lines, but much widened, and the terrific vortex of hydrogen presents the lines bright in some cases. Therefore there is but little absorption of hydrogen in the umbra. But approach of hydrogen with the unheard-of speed of 300 miles per second has been seen at or near the edges of the spots, while a downrush was noted in the center. The mystery of sun spots is by no means settled, but this ascent and descent presents a most impressive picture of the grand scale upon which the circulatory gases of the solar disc take place. 122 RADIANT ENERGY. : ;': v Cut 52. Professor S. P. I,angley's Magnificient Sun Spot. (Drawing.) Cut 52 is one of the most magnificent drawings of a sun spot ever made. The marvelous tongues, filaments, jets and spray over the black abyss are beyond comprehension. All over the ad- jacent regions are shown the "rice grains" and rough granula- tions always seen on the sun. This superb delineation was made by Professor S. P. Langley at Allegheny, Pa., Observatory. It is still admired by solar physicists throughout the world. . Readers of this series are specially requested to study and fully understand the properties of that wonderful space, the magnetic field, before the next paper appears. It will be on the effect on the earth caused by these jets across sunspots. The effect is magnetic, therefore the electro-magnetic field should be comprehended. Any work on electricity or higher physics will give the explanation. RADIANT ENERGY. 123 XVII. JETS ON THE SUN THEIR EFFECT ON THE EARTH. In the sky's framework she has shone with splendor The goddess has cast off the robe of darkness, Waking up the world with ruddy horses. Upon her well-yoked chariot Dawn is coming in. ';j A Rishi's Hymn to Dawn, Rig Veda (1-113). And rival tempests rush amain From sea to land, from land to sea, And raging form a wondrous chain Of deep, mysterious agency. Michael in Goethe's Faust. And other suns perhaps, With their attendant moons that will descry, Communicating male and female light Which two sexes animate the world. Milton. The immediate effect is now known to be electro-magnetic. The results of a century of observation all point to this conclusion. When a mighty tongue of white hot matter darts across the abyss of a large spot or cavern on the sun, the equilibrium of the earth's magnetic field is disturbed and the effect is a magnetic storm. The needles of magnetographs throughout the world shiver, trem- ble and oscillate. The vibrations take place on opposite sides of the earth, the impulse not requiring time that can be measured, to pass from the side of the earth nearest, to that most distant from the sun, whether through or around it. 124. RADIANT HN HRGY. These magnetic instruments are self-recording, so no elec- tro-magnetic wave from the sun can strike the earth without mak- ing its own record in the electro-magnetic observatories. These are separate buildings and the framework is bound together with copper nails, no iron being allowed near the delicate apparatus. The oscillations of the needles are recorded bv automatic photo- graphic mechanism driven by clocks, and are complex in detail. They have rendered valuable knowledge of pulsations on the sun. After three centuries of investigation from Gilbert to Tesla, this most wonderful space is still the admiration and inscrutable mystery of all who study that vast science, electro-dynamics. Power is cut out of this space, and the hurrying waves are caught, dragged from seemingly void areas and chained to servitude in the electric light and railways. But the sun is electro-magnetic and waves carrying power, beat and surge against the earth. A magnetic field is space surrounding a magnet. This space may be filled with air, wood, stone, glass, or may be a vacuum, but the waves are not quenched. They flow through all these. A freely suspended magnet in a magnetic field will move, and the earth's surface is surrounded by a magnetic field, which is acted upon by solar magnetic energy. A free magnet will place itself parallel to straight line of magnetic energy, or tangent to a curved line. For all magnetic energy round a magnet moves in lines. Cut 53 shows two poles and the resulting curved lines in the adjacent space. The black square represents a plate of glass lying on the poles of a vertical U magnet. Iron filings are dusted on the glass, when the waves or lines of magnetism at once arrange them into the curves, the curvature being caused by mutual attraction of the poles. If one pole is used, the iron parti- cles will be arranged into straight lines radiating in every direc- tion. Suspend a sewing needle by a silk fiber in the field (cut 53) and it will at once place itself tangent to the curves and come lo rest. But let the field be disturbed that is, become stronger RADIANT ENERGY. 125 or weaker and the needle will move. This is a magnetic storm. And when a jet is hurled across a spot on the sun the disturb- ance reaches the earth in the same time that light does so radi- ance traveling 186,000 miles per second reaches the earth in eight minutes nineteen seconds. The terrestrial field responds at once and every magnetic needle on earth begins to swing, the photo- graphic plate recording every beat, and the clock records the time, so the history is complete. And here again it is impossible to refrain paying another tribute to the invaluable aid of photog- Cut 53. Magnetic Poles and Field. raphy to science. But when the times recorded by the clocks are reduced for differences in longitude, the absolute time of storm is the same for all. MEMORABLE MAGNETIC STORM,, NOVEMBER I/, 1882. This was one of the most violent on record. On November 15, 1882, after an interval of cloudy weather, a view of the sun was secured. An enormous spot was at once seen already ad- vanced on the eastern solar limb 24 degrees. It was in a state of excessive turbulence, since none of the jets were straight, but were twisted, crossed and contorted in every shape. The edges j 2 6 RADIANT ENERGY. of the chasm were notched and indented, while the umbra was traversed by bridges, filaments and photospheric debris. The spot seemed to be in rotation, confirming the theory of vortex or whirlpool motion, for striae, granulations and tufts of incan- descent matter were strewn about the inclined or depressed sides of the penumbra as though impressed with the centrifugal tend- ency of rotary motion. Clouds again obscured the sun until 8 a. m., November iQth, when the sky became clear and remained so four hours, during > : ' ., Cut 64. Sun Spot, 8:30 A. M., Nov. 19, 1882. Jets Starting From Opposite Sides. (Drawn by the Writer.) which the drawings (cuts 54 and 55) were made with eye at telescope, a fine six-inch Clark equatorial, with prismatic solar eye-piece. The disruption of the spot was almost complete, since the 1 5th. The black umbra had become broken into four masses (cut 54, drawn at 8:30 a. m., November iQth), when two tongues were seen starting across from the lower side. At 9:30 a jet of inconceivable brilliancy started over the abyss from the upper side, as shown. The solar prism was covered with black glass to RADIANT ENERGY. i 2 j protect the eye, yet this jet at terrific heat was too bright to look at for more than an instant after it had well advanced, but at the starting was not so brilliant. It became brighter as it moved, a thing not understood. The lower jet also advanced, and the awful tongues grew brighter and brighter. At 10 a. m., or in half an hour, the jets were as shown in cut 55. They had approached so that only a narrow strip of black remained between. They curved toward one another, and seemed at the point of striking in collision. It was watched with Cut 55. 10 A. M., Nov. 19, 1882. White Hot Jets About to Strike Together. intense interest with pencil in hand, ready to depict the scene, just to occur, when a cloud came across the sky and obscured the wondrous spectacle. The disappointment was acute, but one common to astronomers. On the next day the two jets combined into one wide bridge. The spots shown in cuts 54-55 are merely the central por- tions; there were 108 smaller spots around the edges of the penumbra, the interior edge only being drawn, 128 RADIANT ENERGY. And on the other portions of the sun twenty-three other spots were also counted. But the daily press of November I7th was burdened with accounts of widespread magnetic disturb- ance, in some places suspending telegraphic manipulation. The area of turbulence filled that great quadrilateral from New York to Yankton, Nashville and Winnipeg. In Milwaukee the carbons in the electric lamps were lighted, rendered incandescent by cur- rents of electricity flowing in on the wires. At other points, switch-boards in telegraph offices were set on fire and keys melted on the apparatus, while electric balls were seen hovering on the telegraph in Nebraska. The Atlantic cable was in a state ol unrest and more or less disturbance was noted in Europe. This now historic spot was 38,000 miles wide and 87,000 long, the mean of several measures. The jet at the upper part of cuts 54-55 therefore traveled 19,000 miles in thirty minutes. On October 7, 1880, Professor C. A. Young saw an outburst which hurled matter vertically to a height of 300,000 miles, but the jet of November 19, 1882, was horizontal across the spot. On August 5, 1872, he also saw a disruption that cast up white- hot matter at a rate of 120 miles per second, much faster than horizontal speeds. On writing to Europe he received reply that British magnets were in agitation. Including 1882 there were three great magnetic storms, and these coincided almost exactly with the maximum disturbance in the sun spots. However, great spots have been seen on the sun without magnetic unrest on the earth, and conversely, storms without spots, possibly due to prominences not seen. The first and now classical observations of these phenomena were made September I, 1859, by Messrs. Carrington and Hodg- son in England. These two observers were many miles apart, but both happened to be observing the sun at the same time. They simultaneously saw two objects of intense brilliancy, 8,000 miles in length, 2,000 in width, and 12,000 miles apart, suddenly RADIANT ENERGY. I2 9 Cut 56. Total Solar Eclipse. Short exposure Showing Gases Near the Sun Only. appear on the edge of the umbra of a gigantic spot. The bright- ness of these was five or six times that of the adjacent regions of the sun. They both moved side by side over the spot, 36,000 miles in five minutes, and vanished. These were detached masses and did not appear as continuous jets. A great magnetic storm occurred that evening on the earth, and also a magnificent display of the aurora borealis. i jo RADIANT ENERGY. XVIII. TERRESTRIAL INFLUENCE OF SUN SPOT ACTIVITY. "Approach, O Vishnu ! enter thine own body, the eternal ether. Thou art the abode of the worlds." From Ramayana, vii. Not only do jets, darts and bridges across cavernous spots upset the equilibrium of the earth's magnetic field, thus causing balanced magnets to swing, but they disturb the telegraphs of the world, and also cause displays of the aurora borealis ? and at times austral as well. Coincidence of auroral splendors and solar spot action is well marked, and periodicity is clearly established. But the aurora is known to be electro-magnetic. This term now occurs so often in scientific literature that it ought to be understood by all who wish to know about cosmical physics. This is the conservation of magnetism from, or by means of electricity. Magnetism is thought to be a vortex in corpuscles, and if the vortex can be suddenly fixed while in the midst of its motion, like an instantaneous graph of falling water or of a dyna- mite explosion, the result will be a permanent magnet. Steel permits the cessation of motion and fixation of cor- puscles within its particles while iron does not. And steel is iron with the addition of a minute quantity of carbon, one or two per cent only. The mystery hovering round about carbon lies at the root of nature, for the chemical union of carbon with iron renders RADIANT ENERGY. i 3 i the compound susceptible to the most inscrutable wave-motions, oscillations and pulsations, surging through the universe. How can we clutch corpuscles and chain them to ordinary chunks of matter usually called atoms, and thus convert them into perma- nent magnets? Cut 57. Electro-Magnetic Apparatus. The steel needle 3 passed through the electric coil (2) and becomes a ma magnet as at 4. This process is shown in cut 57. No. I is a zinc and carbon cell separating electricity from matter and sending it out on the positive wire, whence it returns to the negative pole. At 2, the wire is coiled around a glass tube, while at 3 is a thin piece of steel having no magnetism, for it will not lift up iron dust. Close the battery circuit, the wire becomes a center of electrical energy. Pass the steel through the tube, take it out at 4 a marvelous 132 RADIANT ENERGY. change has taken place it will hold up a sewing needle, as shown ! This has remained the wonder of all electricians from Faraday to Edison. What mind is able to fathom this mystery? Every wire forming a connection between the terminals of a source of electricity is surrounded by a magnetic field. The mag- netic energy here passed through glass and filled the tube with its lines. The steel cut them out and fixed their potency in its particles, and became a permanent magnet. The steel needle (4) has also acquired a remarkable property in relation to electricity, for if it is placed upon a pointed support, as at 5, and if a wire (CD) be held over it, then will the needle (5), turn in the direction (A B) if the battery circuit is closed. Law. A magnet free to move places itself at an angle with a flow of electricity. This is deep seated in nature, and is the cause of magnets moving themselves at angles to currents in or on the earth; that is, to point north, for if the steel (4) be placel at 6, in any position, it will turn to point north if left to itself. There must be a current flowing from east to west under it, and since the earth turns from west to east, the sun appears to move from east to west, and the sun causes the earth currents. If the sun is torn and tossed by storms, disturbing its magnetic field, the currents induced in the earth at or near its surface will vary, and this will vary the potential of the earth's magnetic field and cause magnetic storms. Passing of the steel from 3 to 4, through the electro-magnetic field of force in the tube, and appropriation of magnetic energy by the particles of metal by the capture of corpuscles, is electro- magnetism. It pervades nature. If the needle (6), anywhere north of the equator of the earth be suspended as shown, without making its south end heavier than the north, then the north end will dip as in 8, 9 and 10. Additional steel is therefore put on the south end to counteract RADIANT ENERGY. i 33 this tendency, if a horizontal needle is wanted. Dipping needles are always inclined by an angle equal to the magnetic latitude, or distance of the needle from the magnetic equator of the earth. In 10, a scale is attached with degrees marked so this angle can be read in any place on earth, while 7 is complete dip circle, as used in all the magnetic observations. South of the earth's magnetic equator the needle would point the other way that is the south end would dip, and the north rise, being horizontal only at the equator. N Cut 58. Magnetic Needle Carried Around a Magnet. This may be seen in cut 58, where a bar magnet is shown, with a needle near it, in several positions. It will be seen that the white end of the needle is opposite the plus pole of the magnet and the black end adjacent to the minus pole. If, therefore, a magnet, hung on a pivot, be carried from the north magnetic pole of the earth south across the equator to the south pole, and past that round through the equator to the north pole again, it will make one complete revolution. In cut 58 the needle is shown as having made half a revolution, having been carried half way around. When a colossal tongue of white hot matter is shot across a sun spot, the needle 5, in cut 57, will swing to either a, b, or e, f , with violence, while the needle 9 will vibrate to g, h, in a vertical plane. This is a magnetic storm. i 34 . RADIANT BNBRGY. RECORD OF MAGNETIC STORM OF JULY l6, 1882. Made at Terminals, New York and Boston. Strengths of Times. Currents in Pressures h. m. (p. m.) Milli-Amperes. in Volts. 12:37 27 100 12:39 3 2 IJ 8 12:39^ 48 177 12:40 44 163 12:40*4 H4 49 2 12:41 68 252 12:43 20 74 12:44 15 55 12:45 1 9 7 12:46 14 52 Resistance of line wire, 2,700 ohms. Between New York and Providence, R. I. P. M. Currents Pressures h. m. Milli-Amperes. Volts. 12:05 9 20 12:07 42 113 12:12 4.3 12 12:15 .8 2 12 :29 280 644 This is a most impressive record. Thus, from New York to Boston, the line resistance was 2,700 ohmns, yet, when terminals were put to earth, the current on the wires due to the storm was strong enough to register 133 milli-amperes (thousandths) at the height of the upheaval on the sun. And between New York RADIANT ENERGY. i 35 and Providence, two hundred and eighty-thousandths of an am- pere, with a pressure of 644 volts. But on the evening of July 1 6th a grand auroral display occurred, and a vast sun spot was in turbulence in high south solar latitude and near the western limb. The telegraphs had been disturbed from New York to Chicago and Omaha during the entire week before the culminating storm and aurora. 136 RADIANT BNBRGY. XIX. THE AURORA AND SUN SPOTS. "Thanks to the light of the rising day, to the dawn longed for, which puts an end to the anxieties and terrors of the night." Vedic Hymn to the Dawn. "At times there are fire-glows, sometimes fixed and persistent, some- times flitting. There are Bothynoe, when as within a corona, the fiery recess of the sky is like a cave dug out of space. There are Pithitse, when the expanse of a vast and rounded fire is either carried about or glows in one spot. There are Chasmata, when a certain portion of the sky opens, and gaping, displays the flame as in a torch. The colors of these are many. Certain are of the brightest red, some of a flitting and light flame color, some of white light, others shining, some steadily, and yellow without eruptions or rays. Under Tiberius Csesar the cohorts ran together in aid of the colony of Ostia as it appeared in flames, when the glowing of the sky lasted through a great part of the night, shining dimly like a vast and smoking fire." From the Latin author Seneca, Questiones Naturales. Lib. I. C. XIV., Capron's Trans. "About this same time Antiochus prepared his second voyage into Egypt : "And then it happened, for the space of almost forty days, there were seen horsemen running in the air, in cloth of gold, and armed with lances like a band of soldiers. "And troops of horsemen in array, running one against another with shaking of shields and multitude of pikes and drawing of swords and casting of darts." Book of Maccabees, II, Chapter V, i, 2, 3. "There was a bloody appearance of the heavens which seemed like fire descending on the earth, in the third year of the iO7th Olympiad and a light seen in the nighttime equal to the brightness of day." Pliny, Lib. I, C. xxxiii. The aurora should be studied with care by means of every resource known. An aurora is the visible effect of obscure un- dulations from the sun, that source of waves, as they come dash- ing on the earth with a speed of 186,000 miles per second. It is RADIANT ENERGY. i 37 known that a wave of light is a wave of electro-magnetic disturb- ance. In a six-months winter, say at the north pole of the earth, the sun is far south of the equator, and none of its rays can shine on the earth's northern pole. But the aurora is very brilliant. It shows many colors, and these flash and glow with rapid variations. The light, although it is caused by the sun, does not come direct, but is caused by the turbulence set up in the earth's magnetic field by electro-magnetic upheaval on the sun. The field of the earth is "tuned" for that of the sun, as are coherers in sympathetic telegraphy and telephony. The aurora is known to be electrical, for magnets and compass needles on ships are always affected. No magnet can be placed near a "current" of electricity, or a static charge without making oscillation. If a bar magnet be broken into two portions, each becomes a magnet with plus and minus poles. If each piece be again broken, the result is four magnets ; if each of these is divided, there will be eight mag- nets, and so on, and there will be as many magnets as there were gross atoms of steel in the original bar. For each particle has an equator and poles, and is animated by a closed circuit of mag- netic energy. This is Ampere's concept, and every magnet be- haves in accordance with it. In cut 59 there appear seven Crookes' wonderful vacuum tubes, with which he approached the doors of a labyrinth lead- ing to the very confines of matter. The air has been pumped out so that only a very minute quantity remains. Thus while the pressure on the outside is fifteen pounds of air per square inch, it is only a minute fraction of this within. The ends of fine plat- inum wires have been pushed through the sides of the tubes when the glass was white hot. Now connect the ends of the platinum wires to the terminals of either a static electrical machine, or an induction coil in action, all in a dark room. Instantly the tubes light up with supernal radiance. Their beauty is beyond descrip- tion. The light oscillates with great rapidity; they glow and RADIANT ENERGY. CROOKE'S TUBES. Cut 59. High Vacuum Tubes. RADIANT ENERGY. i 39 blaze, and their corruscations are the wonder and admiration of all who behold. They look and behave like the oscillatory dis- charges of the aurorse hung up above the poles of the earth. The writer has lighted these tubes hundreds of times with both sources of electrical oscillations, and always with the auroral effect. In the ruby tube, the imitation aurora is shown glowing under the action of high-pressure electricity; while the V-shaped tube, No. 2, looks exactly like the vertical streamers of a pulsating au- rora. The other tubes are of great interest, especially in that vast region of research, molecular bombardment, and cannot here be explained without entering upon an elaborate treatise on mod- ern electricity. Suffice to say that the phenomena on display in these tubes with varying rates of vacuity, are in that mystical place, the dim borderland between radiant energy and radiant matter, if indeed there is any boundary between, for Thomson's corpuscles and Crookes' electrons, although matter, behave like ra- diant energy. And mystery deepens, for both Crookes and Thomson came upon the same bodies smaller than atoms by dif- ferent methods. Cut 60 presents nine Geissler tubes. These have been ex- hausted of air by means of a powerful Sprengel mercury air pump. Then they are rilled with such gases as nitrogen, hydrogen, oxy- gen and the hydro-carbon series, and are then flashed by high po- tential electricity and held before the slit of the spectroscope for analysis of their radiant energy. No two gases vibrate in the same rates and therefore no two give the same colors. But all rates and colors ever seen in auroral streamers, columns and cur- tains are shown in rapidly oscillating electrical discharges in these high vacuum tubes. No new mode is seen in the auroral light. Nine lines have been seen in auroral spectra, but not more than seven at once. The brightest is in the yellow-green, but in one aurora Perry saw the red brightest, in a curved streamer. A magnetic storm was raging at the time, while Capron saw the 140 RADIANT ENERGY. t's Tubes Filled With Hydrogen, Oxygen and Other Permanant Gases for Electrical Researches. green-blue flickering in all parts of the spectrum of the same dis- play February 4, 1872. The great aurora of April 9, 1871, was so brilliant that measures of its spectral lines could be made with micrometer, and nine were measured. In every aurora the green line is present, while the others vary with different apparitions. The red line in the auroral spectrum is due to nitrogen, ac- cording to Vogel, and also the two others toward the violet. The third line in the spectrum of oxygen appears as the fifth in the spectrum of an aurora. Most of the lines are due to air and its gases. But iron lines appear in the spectra of auroral light and the mystery is how can iron vapor exist in air. Vapor is made of exceedingly fine particles, so fine that they are able to exist in the higher regions of the air against gravity for some time, or there is a continual precipitation of iron dust, at least during the period of an auroral display. RADIANT ENERGY. 141 Nordenskjold set up vertical tin tubes in the Arctic regions, and caught fine particles of iron from space. But iron is the most magnetic metal and the aurora is an electro-magnetic dis- turbance. Sounds have been heard at times of auroral displays, and ozone has often been detected by its odor. This can be made in the laboratory at any time by the action of electricity on oxygen. If the Crookes or Geissler tubes, when the electric pressure is pass- cut 61. Carl Bock's Aurora. ing through them, be placed between the poles of a powerful electro-magnet, all the effects are intensified and the colors of the lights in the tubes can be changed to imitate the colors of an aurora by simply increasing or decreasing the strength of the in- visible magnetic field in which the tube is placed. Cut 61 is a drawing of a magnificent aurora of the arch and pulsating type. It was made by Professor Caral Bock at For- 1 4.2 RADIANT ENERGY. sanger Fjord, in Lapland, October 3, 1877. The sky background is green, with yellow in the streamers. The wonder about this aurora was that the arch remained at rest, while the streamers shot up in front with great speed and lateral undulation. It lasted two hours. The axis of the bow or arch was parallel to the mag- netic axis of the earth. RADIANT ENERGY. XX. AURORAL DISPLAYS. "For before sunsetting chariots and troops of soldiers in their armour were seen running among the clouds, and surrounding the city." Jgs- ephus, "Wars of the Jews," book vi 15-3, on Vespasian, Siege of Jerusa- lem. Aristotle, De Meteoris Lib. i, Ch. iv., describes the aurora as an "appearance resembling flame mingled with smoke." Mathew of Westminster, in England, A. D. 555, says (An- nals of Phil., Vol. ix, p. 250) : "Lances were seen in the air." In 1656 pyramids were seen in England in "regionis seris." In Ireland a scarlet aurora was thought to be a shower of blood. All prodigies seen in the sky that were in motion, re- corded in the history of the world, were due to auroral displays, aided by imagination. Aurorse seen just before battles were always seen to be legions of soldiers coming to engage in ter- restrial war. SELECTION OF SPACE WAVES BY THE EARTH. This is all that is necessary for the earth to do, or man. The fountain is the sun and all waves of whatever length are electro-magnetic. For if the two ends of a wire are connected to the opposite poles of any source of electricity, the regions round about the wire instantly becomes saturated with magnetic energy. A piece of steel anywhere in this field will select some 144 RADIANT ENERGY. of the waves, quench their motion, store the energy, and when the steel is removed it carries the energy with it. Iron cannot carry energy away from a field. If the ends of two different kinds of metal be soldered to- gether, and one of the ends be heated, while the other remains cool, a current of electricity will flow if the other ends are con- nected by a wire. The earth contains vast quantities of metals, for the specific gravity of the whole earth is much greater than that of any rocks on the surface layers. The center is particularly dense. There must be vast beds of unlike ores in contact not far below the surface, or, indeed, close to, or on the external sheet. These are warmed by the sun, and thermo-electric cur- rents are set up. But a free magnet, either over or below a cur- rent, or anywhere near it, moves to make an angle with it. The stronger the current the greater the angle, until finally a right angle is reached. If the current varies the angle varies in exact ratio. And the magnetometers of the earth do actually change this angle every day. The thermo-currents flow from east to west, and magnets must point north and south to obey the law and make angles with them. The direction of magnetization of the earth is therefore roughly north and south. The auroral dis- plays are nearly symmetrical with the magnetic poles and axis of the earth. And this axis is roughly parallel to the axis of the sun, while the axis of the earth's rotation makes an angle with the sun's axis of rotation. The sets of poles and axes are not coincident. Thermo-electric currents are weak, and are only able to set up minute daily variations on earth. THE SUN A SPHERICAL, MAGNET. Cut 62 is an inadequate sketch of Professor Frank H. Bige- low's exploration of the magnetic field surrounding a magnetized sphere. He finds the flow from plus to minus hemispheres, as RADIANT ENERGY. indicated by the arrows. Let the sphere be the sun, then to the extreme right is a minute dot, the proportionate size of the earth. It is being struck by a wave front of magnetic radiation from the sun, which disturbs the field. Below the sun are shown two terminals of an induction coil used in wireless telegraphy and phony, in setting up waves. To the extreme right is the coherer, in a distant receiving station. It is also being hit by the same kind of wave-making impact on the earth. The wave makes the loose particle of metal between the knobs in the glass tube cohere into a wire for each dot and Cut 62. Bigelow's Spherical Magnetic Field. dash, and thus switch in a local battery. The process is cutting waves out of space. The earth and coherer are both doing the same thing with the same kind of waves, known to be electro-magnetic. The sun and the coil evidently do the same kind of work; that is, an explosion on the sun. The zig-zag between the knobs is lightning, has a pressure of 750,000 volts and length of 24 inches in the Los Angeles-Avalon space telegraph, and 42 inches in the distance apparatus just installed in Japan. The disruptive discharge is oscillatory ; that is, darts both ways from knob to knob, with terrific velocity and loud snapping noise thunder. 1 4.6 RADIANT ENERGY. But every oscillation sends out a wave, like a stone falling in water. If the two knobs be drawn apart, the lightning no longer has potential great enough to break down the air, so it expands into a brush of blue light electricity, like the bristles of a paint brush if widely separated. Many flashing aurorse have been seen with every appear- ance of a brush discharge. Cut (>:->. Curtain Aurora. Cut 63 is the magnificent curtain aurora drawn by Dr. Hayes in the Arctic regions January 6, 1861. Thus: "The space within the arch was filled with black cloud, but its border brightened steadily, though the discharges were capricious ; now glaring like vast conflagrations, now beaming like the glow of a summer morn. More and more intense grew the light, until from irreg- ular bursts it matured into an almost uniform sheet of radiance. Toward the end of the display its character changed. Lurid fires RADIANT ENERGY. flung their awful portent across the sky, before which the stars seemed to recede and pale." An account by the writer, written on April 17, and widely published in scientific journals : GREAT AURORA APRIL 1 6, 1 882. "April 16, 1882, will pass into the history of astronomy as an eventful day. From morning to night the solar surface was in violent agitation. Colossal centers of cyclonic activity were watched in telescope during the entire day. There were in spots counted from 8 a. m. to sunset, the largest being 67,000 miles long and 48,000 wide. It was seen on April i5th, fifteen degrees on the eastern limb. Throughout the I5th it did not display unusual turbulence, but during the night activity set in, for on the next morning its internal structure had changed completely. It was cut into four portions by bridges which did not maintain Iheir positions for an hour. They were widening, contracting and bending into ever-changing forms. They were much whiter and hotter than the solar disc. At 9 a. m. two tongues were seen pointing toward each other from opposite sides of the spot. At 12:30 p. m. the ends of the jets met and passed, leaving black space between. Shortly after they began a curvature toward each other, which, at 2 p. m., formed a circle, clearly a cyclone. "At 9 p. m., while viewing Wells' comet in the telescope, it suddenly vanished. Looking out the dome to observe the cause, its obscuration was found to come from the rapidly rising arc of an aurora. The advancing apparition presented a yellowish- green arc of a circle, in altitude 18 degrees, half way to Polaris, and whose ends rested on the eastern and western horizons. The width or the arc was 55 degrees ; clear sky revealing Cassiopeia, being below it, near the northeastern horizon. The center of the arc did not appear to be in line below Polaris, so its deviation was measured with the declination circle. The eastern end of 148 RADIANT ENERGY. the arc was 15, and the western 25 degrees north of the equator, so the axis of the arc was inclined 10 degrees east of the axis of the earth. The streamers above the arc were parallel to the dipping needle. "For nearly an hour the phenomenon developed no sign of coming grandeur, but at 10 p. m. three pillars of crimson light shot up to an altitude of 40 degrees from the western extremity of the arc, while a few yellow streamers ascended in the east. These outbursts seemed to be a preconcerted signal with the celestial pyrotechnists, for within two minutes the whole arc flashed and trembled, and then bodily expanded, ascending eight degrees. A halt was made, which lasted not more than a minute, when two flashes in rapid succession were sent throughout the widened arc, now 20 degrees broad. A mighty upheaval fol- lowed, the apex of the band at once lifted to Polaris, altitude 41 degrees, filling the northern heavens with supernal light bright enough to read by ; but the terminals on the east or west did not draw nearer the equator, the energy being central. The great aurora reserved its forces a few moments, and then discharged, simultaneously, hundreds of columns of scarlet, violet and light yellow flames, instantly converging at the zenith. This display waned only to make way for another advance still more mag- nificent, and so on throughout the night, outburst succeeding out- burst in rapid movement, until the rising sun put out all lesser glories. "From midnight to I a. m. the action was at its height, the whole northern heavens, from horizon to equator being belted and banded with varying streamers, while flashes were incessant. A wave would appear on the north horizon and instantly rush to the zenith. Each impulse produced curvature in the straight columns, which at once became straight again until another dis- turbance rose up within a few seconds. The whole northern hemisphere quaked with the rapidity of lightning without cessa- RADIANT BN HRGY. i 49 tion during the hour of maximum unrest, each upheaval hurled light directly to the zenith, with great velocity, whence it slowly drifted south, descending as far as Scorpio in the southern heav- ens, something unusual in northern auroras." Professor S. P. Langley, of the Allegheny, Pa., Observatory, wrote on the I7th : "The auroral streamers converged to a point 10 degrees south of the zenith, while the fluctuating light seemed to pour upward incessantly like a pale flame. My object in writ- ing is not so much to describe the aurora, however, as to call attention to the fact of its coincidence with a remarkable sun spot, which is now visible to the naked eye if defended by a smoked glass. We have had no such solar visitant for over ten years. It consists (at the time I write) of two large and five small nuclei, united by penumbrse, traversed by "bridges" of intense brightness. The area may be given in round numbers, at a minimum, as a thousand million square miles." The heights of aurorse are from 25 to 130 miles, and some are seen in America and not in Northern Europe, and vice versa. Cut 64 is a most valuable record. It was made by Professor Loomis from a search of the records of the world. It shows the number of sun spots, auroras and magnetic storms for 100 years, from 1775 to 1875. Figure I shows the number of auroras by the height of the vertical black lines. The ordinates (the numbers to the left), are numbers of auroras. Thus, in 1786, there were 117, and in 1810 only four. Figure 2 is the average range of magnetic declination that is, the number of degrees the needle moved every day. Thus in 1786 the average for the year was 12 degrees daily, the high column in figure 2 comes under the high number of auroras above it in figure I. In figure 3 is the number of groups of sun spots in 1786, about no groups, and it, too, is in line with the high columns of RADIANT ENERGY. Fig:2. LOOMIS JB2O L83O 1H4.O l. r >0 1860 187: Cut 64. Record of Sun Spots and Magnetic Storms. auroras and storms among the magnets. The lines of abscissas are intervals of ten years. The coincidence is complete. In 1810 they were all reduced to a minimum. However, in 1805 there were quite a number of spots, but few auroras, while in 1870 they agreed again. Another spot maximum is due in 1903-4, and it is hoped the earth will have lively auroral and electro-magnetic times. RADIANT ENERGY. i 5 i XXI. THE SUN'S POTENTIAL. "For consider Purna, that great vault of space, the sun shines forth and there is light, the clouds gather and there is darkness, the winds arise." Kiounen Sutra, Chinese Scriptures. ''But if darkness, light and sight be separate and independent one of the other, then if you. remove light and darkness, there is nothing left but void space." Buddhistic Sutra. "As one sun illumines the whole world, so does the one spirit illumine the whole of matter. O! Bharata." Hindu Baagavad-Gita, Ch. XIII. "When I see the sun and moon in eclipse, and the wise man in want, then I say Fate is master." Hindu Hitopadesa, I, 44-6. "Light, seeking light, doth light of light beguile." "Love's Labor Lost," Act I, Sec. I. LIGHT POTENTIAL, OF THE SUN. Many measures have been made of the sun's light with sev- eral kinds of photometers. Its intensity has been a source of wonder to all who have ventured on the problem. Light varies inversely as the square of the distance, and the sun is 93,000,000 miles from the earth ; therefore, its intensity is inconceivably greater on the sun than here, yet will destroy the retina of the eye and far surpasses any light that man is able to make. The light of the sun comes from the white-hot carbon enve- lope. But not only is a part absorbed by the gases above it, but its character is changed in color and activity. Professor S. P. Langley has shown that if the sun had no atmosphere, the surface would shine at least two or three times brighter than it does, and 152 RADIANT ENERGY. with a blue-violet color, like the light of an electric arc, playing between carbon terminals. Most of these refined researches were made by Langley on Mount Whitney, California. Absorption in the solar atmosphere can be seen by a college class at the same time as shown in cut 65. This represents the eye end of a telescope whose object glass is pointed at the sun. The lenses of the eye-piece expand the light upon a card. Make two holes in the first card, one in the center Cut 65. Image of Sun on Screen. and one near the edge of the solar image, and receive the light on another screen. If the brightness of the spots is measured by a photometer (light measurer,) it will be found that the brilliancy of the circle near the edge of the sun is only two-fifths that in the center, having passed through a much greater depth of gases on the sun. Now light and also heat or any other radiance varies inversely as the square of the distance is shown in cut 66, where the in- tensity of light from C, falling on the areas (i, 2 and 3), are equal. But the space in 2 is four times and in 3 nine times thai RADIANT ENERGY. i 53 in i, while the distances are 2 and 3, and 4 is the square of 2 and 9 of 3. The distance of the earth from the sun is equal to i, and of Venus .72. The square of I is i, and of .72 is .52; hence the quantity of light and heat received from the sun by Venus Cut 66. Variation 'of Light With Distance. equals i divided by .52, or 1.9, almost double that received by the earth. Human beings could not live on the equator of Venus. Great skill has been employed in the measurement of radiance received on earth from the sun. This is done by comparison, as may be seen in cut 67, which is a meridian photometer in out- p^xT /^D Cut 67. Meridian Photometer in Outline. From Professor Young. line, for the measures are made, when the sun is on the meridian, to secure the least depth of the earth's atmosphere, and, therfore, its minimum absorption. Light from the sun is reflected by the mirror of the heliostat through a lens into a dark room. Rays, ENERGY. after passing the focus (F) of a convex lens, always diverge. Suppose the lens to be half an inch in diameter, it will form an image of the sun on the screen (S S). The size of this image depends on the distance of the screen from F. Suppose its dis- tance is such that the circular image is 10 feet in diameter; that is, 240 times the diameter of the lens. Then the illumination of the disc on the sceen will be i-57,6ooth that of the sun, after allowing for absorption by mirror, lens and screen, for 240 squared is 57,600. Place a rod like a pencil on end at P and a standard candle at C. Move the candle back and forth until the shadow cast by the pencil at I equals in darkness that cast by it atj. Hundreds of measures have been made on different days with varying clearness of the air, when it has been found that a standard candle must be placed at a distance of one meter from the screen to make the two shadows equal, one by the candle, the other by the sun. A standard candle adopted by physicists is made of sperm and burns 120 grains per hour, or 7.776 grams. When the sun is on the meridian and allowance is made for absorption by air and glass, it illuminates a screen 70,000 times as strongly as the candle. The distance of the sun is 150,000 million meters. Square this, multiply the product by 70,000 and the result comes out 1,575,000,000,000,000,000,000,000,000 candle power. This is the quantity of light emitted by the sun, anc is different from intensity, for an immense surface, even if not very brilliant, can radiate a large quantity of light, while the quantity of light emitted by any square unit as a square inch or centimeter determines the intrinsic brilliancy. Computing, it is found that the sun's carbon winding sheet is 190,000 times brighter than he candle flame (Young) and 150 times brighter than a calcium light, and from two to four times more brilliant than the electric arc light, all of which lights appear as dark spots when held between the eye and the sun. RADIANT ENERGY. 755 XXII. HEAT POTENTIAL OF THE SUN. Whence are thy beams, O sun ! Thy everlasting light. Ossian's "Poem to the Sun." Sunshine, broken in the rill, Though turn'd astray, is sunshine still. Moore's "Lalla Rookh" ("The Fire Worshippers"). Substance, and accident, and their operations, All infused together in such wise That what I speak of is one simple light. "Paradise, XXIII," Longfellow's Trans. There is only one Deity, the great Soul. He is called the Sun, for he is the soul of all beings. "Rig Veda." The glorious lamp of heaven, the radiant sun, Is nature's eye. Ovid's "Metamorphoses," line 165. THE PIEAT OF THE SUN. Not less skill has been employed in measuring long heat waves than in short light undulations. Many eminent physicists have brought instruments of ever-increasing accuracy to the task. Some of these are complex and too technical to be explained here. Perhaps the simplest and first of all, was Pouillet's pyro- heliometer (sun-heat measurer), as shown in cut 68, where A is a metal cylindric box one decimeter in diameter and of a thickness required to hold TOO grams of distilled water. The 156 RADIANT ENERGY. upper surface is blackened with lampblack, for this is the best absorbing substance known, while the other parts are of polished silver, for this is the worst absorbing metal; the object being to secure all the radiance possible in the water box. The bulb of a sensitive thermometer is immersed in the water, the tube serving as an axis. The black surface of the box is placed at Cut 68. Pouillet's Pyroheliometer. an exact right angle to the sun, which is found when the shadow of the box coincides with the circular sheet of metal B. To use it, a screen is held between box and sun for five minutes. The water becomes of the same temperature as the air or sky, which temperature is read on the air scale at T. The screen is then removed and radiance allowed to fall on the black box for five RADIANT ENERGY. 757 minutes, when screen is replaced and thermometer again read. The difference between these readings the first and second five minutes gives data for temperature raised in a cylinder of radiance one decimeter in diameter in 100 grams of water in five minutes. Were it not for allowances to be made for the small quantity of heat not absorbed by the lampblack and the amount absorbed by the earth's air the result would give the amount of heat that escaped the sun's atmosphere and fell on the earth. Violle's actinometer and other forms are more accurate than Pouillet's, but after many thousands of determinations, by all these in all conditions of the air as to transparency, dust, water vapor, etc., the results agree fairly well. THE SOLAR CONSTANT. This is the result of a hundred years of research and is the constant or invariable quantity of heat that reaches the earth from the sun. Its quantity is beyond all concept. It surprised the early physicists and now fills with awe all who comprehend its mighty import. But really none can comprehend. How much to allow for absorption in the atmosphere was found by taking a bolometer up to different mountaiin heights. This is one of the most remarkable instruments ever invented, and will be fully described just before the subject of radiance from the stars is taken up. By its use and subsequent mathe- matical computation by some of the ablest mathematicians, the following value has been obtained : THREE CALORIES. Thus, Professor S. P. Langley, after extended and accurate research on Mount Whitney, California, at an altitude of 14,500 feet, says : "My conclusion is that we can adopt three calories as the most probable value of the solar constant." 15$ RADIANT ENERGY. Nearly as much hard work has been clone to find this quan- tity as has been performed in finding the distance of the sun. This value is now adopted by the physicists of the world as the most accurate and comprehensive solution of the great problem. A calorie is the quantity of heat required to raise the tem- perature of one gram of water one degree centigrade ; that is, if the earth had no atmosphere, solar radiance would raise the temperature of one gram of water three degrees centigrade per minute for each normally exposed square centimeter of the earth's surface. The line A B is one centimeter in length ; a square whose sides are of this length would be a square centimeter, and a cube of the same width, length and height would be a cubic centimeter. If the cube were a little box it would hold just one gram of distilled water. And one degree centigrade equals i 4-9 degrees of the ordinary Fahrenheit thermometer. Clearing of all metric values and reducing to ordinary English numbers, the quantity of solar radiance falling on every square yard of the surface of the earth at right angles to the central ray of the sun, if it could be converted into mechanical power in a perfect heat engine, would be what is technically known as slightly less than three horse-power. And this acts continuously the stupendous flood of energy since the appearance of man on earth has not decreased, at least, within the period since the invention of stone writing, for delicate plants now grow and produce fruit and flowers in Egypt, Mesopotamia and India that are sculptured on the primeval walls and pillars of granite in the palaces of Memphis, Thebes, Nineveh, Ecbatana and Ellora, and whose fragrance and beauties were sung by our primitive and poetic ancestors round about the base of the Hindu Kuh, 800 miles east of the Caspian sea, B. C. 5,000 years. The climate of the early Aryans has not changed the solar heat has been constant since the Vedic poets sang. But from RADIANT ENERGY. that day until now, the time is merely equal to one swing of a pendulum in cosmic history. The radiant energy falling on the deck of an ocean liner is sufficient, if it could be utilized, to propel the ship with greater speed than is now obtained from carbon. This radiation received is upon the theory that the earth had no air. The air cuts off fully one-third, and human genius so far is unable to use more than one-eighth of the remainder. Cut 69. Solar Motor, at the Cawston Ostrich Farm, South Pasadena, California. The mighty brain of Edison cannot hit upon a plan to make it more available. The heat engine built by Ericsson had 176 square feet, about 20 square yards of brilliant mirror surface re- flecting the heat upon a boiler. The output of work was three horse-power, while about thirty-five horse power fell on the mirror. Cut 69 is the great solar motor on the ostrich farm in South Pasadena. The circular mirror i a segment of a paraboloid i6o RADIANT ENERGY. of revolution, 33 feet wide at the top and 16 at the bottom. The property of this conic is to reflect all parallel rays falling upon it to a focus. The boiler is a steel tube 13 feet long, in this hot focus. It holds 100 gallons of water and space of 6 cubic feet for steam. The interior of the conical surface is made of up 1788 mirrors, side by side. The whole apparatus is hung on an axis parallel to the axis of the earth, so it will follow the sun, like an equatorial telescope ; and is also furnished with mechanism to raise and lower the mirror when the sun is north or south of the equator. The indicated output is eleven horse-power, with 210 pounds of steam, and it has pumped water at a maximum rate of 1,400 gallons per minute. Why not irrigate the waste places of the earth ? The mirror area is 70 square yards, and therefore receives i3O-horse power of radiation, but uses eleven, or about one- twelfth. Since men appeared on the planet no such problem has presented itself as that of utilizing the eleven-twelfths now going to waste. In the cut, A is the boiler, and E, the engine-house. The radiance of the sun should be caught on countless mirrors, and the energy transformed to work. A million accumulators ought to be stored with the potential form of electricity to move every wheel on earth and turn the darkness of night into the light of dav. RADIANT ENERGY. 161 XXIII. DYNAMICS OF THE SUN. "Horns : the strong bull. Friend of Justice. King of Upper and Lower Egypt. Lord of the periods of thirty years. Like his father Ptah- tanen. The son of the sun : Ramessu Meri-amun. The sun created him. To cause great rejoicing in the city of On, and to fill with riches the sanctuaries of his Creator. Lord of the two worlds : Ra-user-na ; the chosen one of the sun : Ramessu Meri-amun, the son of the sun, who gives life of all stability and purity today as ever after." Literal transla- tion of left-hand face of the pyramidal apex of the Egyptian Obelisk now in Central Park, New York. Erected by King Thutmes III, B. C 1500 in the Temple of the Sun, at On, Egypt. "Thou sun of this great world Both eye and soul." Milton's "Paradise Lost," book V, line 121. VELOCITY POTENTIAL, OF THE SUN. The distance of the surface of the sun from its center is equal to one, and from the sun's center to the earth is equal to 214.5. The square of I equals i, and the square of 214.5 equals 45,973- All radiance proceeds in space as if emanating from a geo- metrical point. And 2 7-10 multiplied by 45,973 equals 124,127, therefore the potential of one square yard of the normal visible surface of the sun radiates 124,127 horse power all the time. Langley showed that very nearly three horse power per 162 RADIANT ENERGY. square meter reaches the earth, and one square yard is less than a square meter, so that the incident energy would be close to 2 7-10 horse power. A "horse power" is that quantity of energy that can raise a stone weighing 33,000 pounds one foot high in one minute. This 124,973 horse power is the energy that gets through the solar vapors. How much leaves the actual carbon surface is not known. But this quantity, the residue, is beyond conception in any finite mind. The union of hydrogen with oxygen develops the most in- tense heat known to be due to chemical activity. SOURCE OF THE SUN^S HEAT. The kinetic theory of matter a vast science in itself is now fully elaborated and chained subject to rigid mathematical law. The heat potential of any quantity of matter in any con- dition, whether in gas, liquid or solid, is known with precision. The quantity in the sun is known, and its potential from a state of excessively rare gas down to its present size and density can be computed, and has been by many eminent mathe- maticians. It can be shown that if the sun were made of pure hydrogen, and should be ignited in an atmosphere of oxygen in sufficient quantity to unite with all the hydrogen, that the heat of this awful conflagration would not keep up radiation for more than 3,000 years. Geology shows that the sun has been pouring floods of heat, light and power upon the earth for inconceivable ages. Whence comes the energy? It is clear that there is no "fire" on the sun. Fire is the union of other modes of matter with oxygen in general, yet other modes unite with evolution of heat. But on the sun modes are too hot to unify and form chemical compounds. At present it is not likely that chemism exists on the sun. RADIANT ENERGY. 163 HEAT OF IMPACT ON THE SUN. If a mass weighing 772 pounds be raised one foot and let fall and strike a rigid body, the precise amount of power re- quired to raise it will be restored and will appear as heat, at the exact instant of striking. And as has been proven, the quantity of heat separated will be just enough to raise the tem- perature of one pound of water one degree F. But the heat appearing in the fall of 772 pounds one foot is equal to that separated by one pound falling 772 feet. This is Joule's equiva- lent. But a body falling 772 feet and making impact on the earth has a velocity at the instant of collision of 223 feet per second. This is the velocity potential of the mass of the earth and ranks high as an important element of knowledge in the possession of man. It can be at once applied to the universe by well-known mathematical equations. Law : One pound of matter in motion with a velocity of 223 feet per second has stored within it sufficient kinetic energy to heat one pound of water i degree F. Now throw this sounding line into the depths of the sidereal structure. With this magic number all space may be explored, and it can be at once computed what quantity of heat will be separated by the cessation of motion of any cosmical mass in space, soon as it is found how fast it is moving. Heat of impact varies as the square of the velocity of the colliding body. If any mass is seen in motion, to find the heat of impact : Rule : Multiply the square of its velocity in feet per second by the reciprocal of the square of 223, which is .00002010899. This number has tremendous analytical power, and there is no escape from its clutch for any mass, if it is moving. If a mass fall from an infinite distance with unimpeded motion, that is, if it had been falling forever, it would take for- ever to fall through infinite distance, its final velocity at instant 164 RADIANT ENERGY. of impact on the earth would be finite and would be 6.94034 miles, not quite 7 per second. Reduce this to feet, square the number, apply the rule, and the result is 27,855 degrees F., or the heat (maximum) that can be separated by any meteorite or comet that may hit the earth if it had no air. The gravity potential on the sun's surface is 27,696 times stronger than it is on the earth's .surface, and its velocity poten- tial is 383 miles per second, from an infinite distance. Reduce this to feet, square the number, multiDlv the product by the above reciprocal, and the appalling result is 81,154,000 degrees F. liberated by impact of a falling body on the sun, if the sun's surface were rigid and it had no atmosphere. That is, if the body had been falling through an infinite distance in an infinite time. If these could obtain, the terminal velocity would be finite, 383 miles per second; yet might as well be infinite, so far as the limitations of the human mind are concerned. Go into space. Twelve million millions miles, or half way to our nearest neighbor, and again apply the methematical for- mula. It is found that the velocity with which a stone would strike the sun falling from an infinite distance, or from a small finite distance twelve trillion miles will differ by not more than one inch per second. So the gravity potency of the sun lies and acts almost entirely within its own immediate vicinity. The sun is not rigid and has a deep atmosphere. So a comet would not give up all its heat, on impact with the yielding carbon envelope. All small comets would be dissipated into cosmic dust and debris as are all small comets meteors that enter the earth's atmosphere, by friction. And further, if the solar surface were as rigid as steel, it is known that a falling body could not hit the sun at right angles to a tangent, but would ricochet like a cannon ball on water, surrendering a part of its heat at each impact. Therefore the maximum 81,154,000 degrees of heat RADIANT ENERGY. 165 could not obtain. This was written in 1882 to combat an alarmist who wrote that if the great comet of that year should strike the sun the earth would be consumed. The terrific heat of the sun is not all caused by a hail of cosmical matter on the sun, although no doubt a minute fraction is, not more than one per cent. F-or if more than this falls, the effect of the increased mass of the sun would soon be detected in the disturbances set up in the orbital motion of Mercury, Venus and the earth. The quantity of matter in the earth is known, and from known laws of kinetics and thermo-dynamics it is shown that if a quantity of matter equal to the i-iooth of the mass of the earth should rain down in small chunks upon the sun with veloc- ities of 383 miles per second, the heat of impact would keep up the radiation poured out by the sun for one year. The earth could apply the output for 100 years. But Mercury and Venus would be disturbed in their flights. Some other and mighty cause must be sought one able to keep up the stupendous flow of heat. 166 RADIANT ENERGY. XXIV. SOLAR HEAT POTENTIAL. "I have praised thy countenance, them creator of the fullness of the earth, Lord of Abydos, who impartest light to thy servants, flashes of light to the darkness of night." Egyptian Book of the Dead. "Driving of Phoebus' chariot Phaeton, Struck by Jove's thunder, Rests beneath this stone. He could not rule his father's cars of fire." Ovid, Met. "At this time Tathagata, from the character which was on his breast, caused to pour forth a precious flood of light, its effulgence like that of the Sun, its rays composed by a thousand colors, penetrating at once through the infinite worlds." Buddha's Teachings to Ananda, Catena Chinese Scriptures. "Mighty power was concentrated at the points of his hands, the son of the sun, Thutmes." Glyphs on top of Obelisk, Central Park, New York. HEAT AND GRAVITY. If a stone weighing one pound on the surface of the earth be placed on the surface of the sun it will weigh 27.696 almost 28 pounds. At carbon "sea level'' on the sun a barometer col- umn, instead of being thirty inches as on earth, would be seventy feet high, if the atmosphere of the sun should be like that of the earth and of the same quantity. But the earth's air, if glaced on the sun, would be flattened to a much thinner layer than now obtains round about the earth. The actual but to RADIANT ENERGY. 167 men invisible surface of the sun must be subjected to enormous atmospheric pressure. Every square inch of the earth's surface is pressed fifteen pounds, and the same kind and quantity of air would press 420 pounds per square inch on the sun. If the solar surface is liquid gas, and in all probability it is, see Chapter XIV then, from the dynamics of liquids it is known that pressure below the surface varies with the depth. At double depth there is double pressure. A place has been found on earth where the depth of the ocean is more than five miles. One cubic foot of water weighs 62^ pounds, so on one square foot of this ocean floor the pressure is 2,000,000 pounds. One average cubic foot of the sun, if placed on the surface of the earth, would weigh 88 pounds, but on the sun it weighs 2460 pounds, for the mean density of the sun is 41 per cent greater than that of water, and gravity 28 times stronger. So 62^x1.41x28 equals 1,475 pounds. How inconceivable the pres- sure below the surface and near the center. The greater the pres- sure the more intense the heat so long as the sun is a gas, whether gas or liquid gas. The thermal energy of matter is known with great accuracy, and the kinetic energy that is energy of motion of gaseous particles is also known with precision, and they are in the clutch of mathematical law, whence there is no escape. Helmholtz first, and many mathematicians since, have many times computed the thermo-dynamics of the sun. All agree within the limits of minute details, that if the sun contracts in diameter nine inches per day, energy in the form of heat would be supplied at its present rate. The angular diameter of the sun is 1,924 seconds of an arc, and the linear diameter is 866,000 miles. So, one second equals 450 miles. But one second is about as small a dimension as can be seen by a good eye in a large telescope. With a contraction of nine (9) inches per day, 168 RADIANT ENERGY. it would require 9,400 years to contract one second, an amount so small that it could be detected only by a micrometer. In Chapter XXIII, it was shown that if a body is moving with a speed of 223 feet per second, and if all its motion in- stantly comes to an end by its striking a body rigid enough to flatten out the moving body into a very thin layer of particles all at once, and if the falling body weighs one pound, the heat liberated will be enough to raise the temperature f one pound of water one degree F. Now it makes no difference whether it falls rapidly or slowly, the quantity of heat surrendered by fric- tion against adjacent particles will be the same. Hence, the heat of the sun is caused mainly by friction, and cessation of motion of particles hitting against each other in the process of contraction. This doctrine is now adopted by all the mathematical physicists of the world. The diameter of the sun was once full thirty million times greater than it is now that is when ex- panded, in all directions to a distance equal to half that of the sun's nearest neighbor. Its radiant energy was then all potential. Each particle on the periphery of the primordial gaseous sphere has been a falling body since, and computation is able to deter- mine the kinetic energy of the entire mass. For the mass is also known. When the diameter of the sun was twenty-five trillion miles its temperature was that of absolute zero 461 degrees F. Con- traction due to central gravity set in and has continued until the present and is now in active operation. After inconceivable ages, long heat waves began to undulate and after the lapse of more millions of years short light waves appeared. The founda- tion of the mathematics of solar potential was laid by the brain of Helmholtz, but his formulas have been much elaborated since his death, notably by Professors See and Doolittle, with aston- ishing results. Thus, while the gaseous cosmic sphere contracted from its original diameter of twenty-five trillion miles down to RADIANT ENERGY. i6 9 the insignificant diameter of seventy-two million miles, when it just filled the present orbit of Mercury, it radiated only one eighty-third of the energy it has since emitted. This vast prob- lem, all based on rigid mathematics, throws much light on the past career of man on earth, upon the glacial epochs and other geo- logical problems. And these relate to the future of men upon the earth. i jo RADIANT ENERGY. TOTAL ENERGY OF THE SUN. XXV. And sitteth awhile on Greyfel On the marvelous thing to gaze, For lo! the side of Hindfell enwrapped By the fervent blaze, And naught 'twixt earth and heaven Save a world of flickering flame, And a hurrying, shifting tangle, Where the dark rents went and came Saga of the Volsungs. He opened the great gates in the darkness shrouded ; The fastenings were strong on the left and right. In its mass he made a boiling. * * * the night be overshadowed * * * until the shining of the day. His [the sun's] horns are breaking through to shine on the heavens. On the seventh day a circle he begins to swell, And stretches toward the dawn further, when the * * * Fifth tablet of Creation Myth, primitive Babylonian script. HISTORY OF THE SUN. When our sun had a diameter of twenty-five million million miles, which it had when extended halfway to its nearest neigh- boring sun, a volume of it, of the size of the earth, contained a quantity of ultra-gaseous matter which^ if condensed into one chunk, and brought to the earth's surface and weighed, would weigh 127 pounds. The volume of the earth is 260 billion cubic miles, so it required 292,000 cubic miles to contain matter RADIANT ENERGY. 777 weighing one grain. A piece of brass of the size of this square, one-fortieth of an inch thick, weighs one grain. This is easily computed for the sun, planets and moons in the solar system contain a mass of two octillion tons, nearly. The primordial solar nebula must have been at the absolute zero 461 degrees F., for two of the particles must either hit to- gether to separate heat by friction, or they must unite chemically. But they could do neither when long distances apart, for every one must gravitate toward the center of gravity of the whole mass. Since a cubic space inclosing 292,000 solid miles would .be 66 miles on each side, the little sheet of brass, if cut into 292,000 portions and equally distributed, would be one mile apart. Nothing but the Thomsonian corpuscles, the i-ioooth of the mass of the unit hydrogen particle, could occupy the space. And they were not very closely packed. The mass began contraction at an exceedingly slow rate, for gravity is weak at a distance of i2 J /2 trillion miles. All the heat radiated from that time has been caused, so far as science can now see, by collisions of the particles. For chemical union cannot take place in terrific cold or heat. Chemism is completely arrested by the cold of liquid air, and this is hotter than the absolute zero. If at any time the temperature of the subsiding cosmical sphere was such that two or more phases could change their rates and unite into a compound, all such combines have long since been broken up by the immensely greater heat of friction now resident in the sun. For no spectroscopist believes that compounds now exist in the solar globe. It is far too hot for the presence of either "fire" or chemism. The original gaseous sphere kept on shrinking, each particle moving on straight lines, and gradually nearing each other. Let this process continue for unnumbered eons, until finally the whole had subsided to the present orbit of Neptune. Its diameter then would be 5,580,000,000 miles. Again computing its density, 172 RADIANT ENERGY. it is still found to be 16,695,000 times less dense than the ex- ceedingly rare gas, hydrogen. All students of chemistry know how attenuated is the elusive hydrogen, and with what care it must be kept from escaping, for air is 14.44 times more dense. Platinum just begins to emit light when its temperature is 525 degrees C., and the carbon filament in an incandescent lamp bulb at 390 degrees, iron at 378 and gold at 417 C. Therefore, when the sun's periphery reached Nep- tune's distance, it was yet enshrouded in primeval darkness and invisible from space. And it is doubtful if its temperature was much, if any, above the absolute zero. From expansion of Helmholtz' original formulas of solar heat potential from primordial gas to solid, Dr. See has com- puted the entire quantity evolved by the impact of all the particles in two octillion tons of matter and finds it to be 49,048,200 de- grees F. This is the heat separated by contraction from either an infinite diameter, or from a diameter of only 25 trillion miles. In Chapter XXI it was shown that the terminal velocities of col- lision on the sun of a stone that started to fall at an infinite dis- tance, or from a distance of 121/2 trillion miles would differ only by a fraction of an inch per second. And in these researches into heat potential it is now found that if the original gaseous mass began to contract from an infinite diameter, or from a finite diameter of say 25 trillion miles, that the difference of the heat output is small; so velocity potentials and the potential of heat agree in these elaborate analytical investigations. Coming down to the Neptunian orbit and again applying the formulas, it is found that if the primitive gaseous mass began to contract even at that small diameter, the quantity of heat liberated would be 49,040,750 degrees F., only 7,250 degrees less than if it had subsided from an infinite diameter, or a finite of 25 trillion miles. RADIANT ENERGY. XXVI. THE ANCIENT SUN. "So, I wot, was earth melted in the glare of burning fire. Then, troubled in spirit, he hurled him into wide Tartarus." From Hesiod Theogony. The mysteries of catalysis are being exploited in the effect it has in relation to life. This is the action of a mode of matter on other modes causing them to unite without being itself af- fected. Finely divided platinum is a catalytic agent, and so is a sheet of platinum if absolutely clean. Thus : alcohol dropped upon powdered platinum becomes changed to acetic acid, the platinum suffers no change whatever, except becoming heated. If formic acid comes in contact with fine platinum particles, it is changed to carbonic acid. If platinum foil is put into a me- chanical mixture of oxygen and hydrogen, a chemical union begins, resulting in the formation of water. The platinum be- comes hot; after the process is complete it cools, and no change is noted. The metal can repeat the work indefinitely, with no apparent exertion or energy and the mystery is where the en- ergy comes from. All this has been known for years to chem- ists. But now comes the bio-chemist Loeb of Chicago and ap- plies this remarkable action to the production of the first life on the inorganic earth. Thus life might have been caused by the mere presence of a third mode of matter. These promoting agents are 174- RADIANT ENERGY. called enzymes (ferments). Modes besides platinum act as en- zymes, gold, silver and others will thus act. Thus the enzyme, called oxydane, in the lungs enables oxygen of the air to be assimilated and sustain life, while many other enzymic agents are found in the living body. He has apparently shown that all life is due to the action of the enzymes. (See Loeb's Columbia College, N. Y., lecture.) But this action has all along been supposed in these notes. Since enzymes suffer no change, and as the sum of energy in existence is constant, these bodies merely direct rad- iance already saturating space, constantly poured forth from countless suns. For actinium and polonium perpetually direct waves against and through other bodies, being themselves with- out change. In all researches into the physics and chemism of the primi- tive gaseous sphere, catalysis has not been introduced. This is one of the most mysterious activities in nature. It is action by influence. Professor Charles E. Munroe (Proc. Am. Ass'n, Cleveland, p. 119) "finds in the behavior of compound radicals, and in the change wrought by the factors of time, mass and temperature, positive evidence of the effect of environment and qualifying conditions in determining the production of species." That is, chemical union is in many cases determined by what is adjacent. Applying this to the dwindling sun it is seen that particles might approach the center side by side for ages and not unite until a third particle was encountered which by its mere presence causes them to unify without itself suffering any change, for it is still able to cause others to unite on its long flight to the condensing central sun. Heat appears when differing phases of matter have their rates changed by uniting, or before, so they will unite; and if the activity is intense enough, light radiates ; but in the archaic mass neither was liberated for untold ages of subsidence, vast periods of weak catalytic action, and eons of rarely oc- RADIANT ENERGY. 775 curring collisions. Affinity, heat and light are late products of the sun. This theory that catalysis was the first mode of energy that began to work on the primordial mass is offered for what it is worth, if anything. For later, affinity laid hold on matter, and wrought ; but this is not catalytic. Electro-chemism and polarity, so ably treated by Berzelius, Faraday and Ampere, most fascinating subjects, must be omitted. As soon as two corpuscles united by the mere influence of a cata- lyst they became centers of increased activity, but they all fell toward the forming sun in the center. After great subsidence, through vast periods of time, the sun became smaller, with liberations due to increased collisions, of heat and then light, succeeded or preceded by electricity, elctro- magentism and polarization. All phases of energy appear now in the still condensing sun. The monads of Liebnitz, pantogen of Hinrichs, protyle of Crooke's; vortex rings of Kelvin, atoms of Aristotle and Lucretius and every other concept, ancient or modern, are comprehended and included in Thomson's corpuscles and Crooke's electrons '"bodies smaller than atoms." These fill every requirement made by physicists and mathematicians of all ages in striving to account for the successive evolutions through which all matter must pass. Catalytic force is ''that substances by their mere presence, and not by their affinity, have the power to rouse latent affinities, so that compound substances undergo reaction and a greater electro-chemical neutralization occurs." Berzelius. "A catalyst is any substance which alters the velocity of a chemical reaction without appearing in the final product." "There seems to be no kind of chemical reaction which cannot be cata- lytically influenced, and no chemical substances, whether elements or compounds, which cannot act catalytically." "The presence of hydrogen ions accelerates most chemical re- 776 RADIANT BNBRGY. actions, so they must be regarded as catalysts of great gener- ality; and there are especially among the enzymes, specific cata- lysts which only exert their accelerating action on perfectly definite substances." "We have three different means of influencing the velocity of chemical reactions : temperature, concentration and catalysis." "Oxidation of napthalum by means of sulphuric acid with speed, can only be brought about in the presence of mercury." "A trace of gas may cause the liberation of an entirely dispro- portionate amount of another gas." There are four phases of catalytic activity known: First, release in supersaturated systems ; second, catalysis in homeo- geneous mixtures ; third, catalysis in heterogeneous mixtures ; fourth, enzyme action. (Professor Oswald, "Nature," April 3, 1902.) If the hypothesis of primeval catalytic action is accepted, then a host of difficulties that have so long troubled physicists and chemists in accounting for the successive steps in the evolu- tion of the sun will vanish. For corpuscles are known to be surrounded by a field, for a long time called "sphere" of action. Thus heat and light are recent; the sun has been invisible until lately. But electricity may not be merely a late worker, for in- deed it may be the primordial catalyst. RADIANT ENERGY. 777 XXVII. THE RADIANT SUN. "After having produced the universe, He, whose power is incom- prehensible, vanished, again absorbed in the supreme soul." Laws of Manu, Bk. L, Shloka 50, Archaic Hindu Phil. Professor Langley has shown that of the total amount of radiation from the sun, 19 per cent is in the visible portion of the spectrum. There is but one kind of energy radiated from the sun the light, heat and chemical effects depend entirely upon the state or condition of the matter upon which the differing wave lengths may happen to fall. Here is a quotation from one of the most eminent physicists which the world has ever seen : "Up to 1872 it was almost universally believed that there were three different kinds of entities, actinic, luminous and ther- mal, represented in the spectrum. There is one radiant energy which appears to us as 'actinic/ or 'luminous,' or 'thermal' radia- tion, according to the way we observe it. Heat and light, then, are not things in themselves, but different sensations in our own bodies, or different effects in other bodies, are merely effects of this mysterious thing we call radiant energy." S. P. Langley, Proc. American Association Science, Cleveland session. The Italian physicist Melloni says : "Light is merely a series of calorific indications sensible to the organs of sight, or vice versa, the radiations of obscure heat are veritable invisible radia- tions of light." RADIANT ENERGY. Melloni wrote this nearly sixty years ago, in 1843, but it was not adopted until Langley by his elaborate researches, more refined and complex than all preceding, proved it. The doctrine of one radiant energy is now adopted by the great physicists of the world. It only remains now for them to say there is only one matter. From Helmholtz' formulas it has been shown that if the sun, whose mass is two octillion tons, contracted from an infinite diameter to a diameter down to the present diameter of the orbit of Neptune, the total heat separated by friction and collisions of its particles, was sufficient to raise the temperature of two octillion tons of water 7,202 degrees F. When it collapsed to the present distance of Jupiter diameter one billion miles the heat liberated would heat two octillion tons of water 43,960 de- grees F. and that contracting from an infinite diameter or from a finite diameter of twenty-five trillion miles down to its present diameter 866,000 miles, the heat sent into space has been suffi- cient to heat two octillion tons of water to a temperature of 49,050,000 degrees F. For it is known just how much work would be done, if one carried a ton of matter away from the sun to twelve and one-half trillion miles, or to any distance even to infinity. To the non-mathematical reader it is well to state that when a formula is applied, at varying distances, rates, pressures, etc., they often run out toward the infinitely small or infinitely large. Since the law of variation of the formula in question is known, it is also known with unerring accuracy when the formula will come to an end. And the work done in carrying a mass away from the sun that is, work of lifting the mass as a stone is lifted on the earth is equal to the work of drawing it in from space. Thus the gravity potential at any distance from the sun is easily com- puted, and from thermodynamic laws, the heat equivalent of work RADIANT ENERGY. i 79 is known. The heat equations have been solved on the hypothesis that the sun in the long period of its subsidence was homogen- eous throughout and the vast quantities of heat seem large enough. But Anne Sewell Young of the University of Chicago made computation with the formulas of Helmholtz on the theory that the sun was all the time more dense in the center and there- fore the entire mass was not homogeneous. And she proved that if it were denser in the central portions, the heat would be greater ! But the mighty power of the sun is exerted in space near it. For if the sun contracted from a diameter of twenty- five trillion miles, or began to contract at a diameter equal to that of the earth's orbit, or 186,000,000 miles, the heat output would have been 48,819,600 degrees F., which, subtracted from 49,050,000 degrees, equals 231,000 degrees, or only 1-21 5th part, was radiated from the beginning of contraction until it dwindled down to the insignificant diameter of the orbit of the earth. Therefore, when the periphery of the shrinking sun was passing the earth's orbit, it was beyond a doubt invisible from space, from any light due to rapid rates caused by heat. Computing again at the orbit of Mercury, i-83d of the heat was poured into space since it began to contract. Make the sun twice its present diameter and again apply the formula, and the result is that in subsiding to that small diameter, it lost only half its heat. The best estimates of physicists are that the sun is radiating heat enough to reduce its temperature 2^/4 degrees per year, and 49,050,000 divided by this gives 21,800,000 years as the life of the sun. Helmholtz made it 22,000,000 years. New- comb says not much above 20,000,000, but no mathematician com- putes more than 22,000,000 years. It is considered that it has been radiating heat 18,000,000 years and has 4,000,000 yet to run its mighty furnace. All these deductions are made on the assumption that all the heat has been caused by contraction. But chemism must have 180 RADIANT ENERGY. produced some, and the fall of meteors and comets a fraction more. But whatever heat was formed by chemical union has surely been counteracted by the work done since in dissociation, for none hold that there are compounds now withstanding the terrific heat. So the times given are probably not far from the truth. STEFAN'S LAW. ''Radiation varies as the fourth power of the temperature." This is an important law, for heat an iron 1,500 degrees and measure its rate of radiation ; then heat it to 3^000 degrees and measure again ; the radiation will be sixteen times as rapid, for sixteen is the fourth power of two. Thus, if the sun ever gets to be twice as hot as now, the radiation will be sixteen times as intense and destroy all living beings on Mercury, Venus, the earth and Mars, if at that time the quantity would be sufficient. This is, however, a mere specu- lation, for if the rate of radiation should double, it is likely that the sun would be much smaller than now, with far less surface, and the quantity of heat much less, although more intense. For one can stand near an arc light heated to several thousand de- grees, with the most intense radiation, while it would be impos- sible to stand anywhere near a large stove heated to the same temperature. From Stefan's law it is seen that if the sun has ever varied its temperature much, the rate of radiation has changed violently. These fluctuations would have marked effect on the geological career of the earth. LANE'S LAW. An American mathematician, Mr. J. Homer Lane, discovered by analytics a most remarkable law of radiation. Law : "A gaseous sphere, losing heat, under its own gravity, must become hotter until it ceases to be a perfect gas." RADIANT ENERGY. /*'^- /v -' 764,OOO j 71 * o^ 12. OO / '-'TJ'-' / Altair . . . O 2O I,O7I,72; Q4- 16.00 O2 Hridani .O IQ ' O >O J 1,085,600 ixt IOO 17.00 1830 Groombridge . j.y O 17 1,^86,6^0 147 / 2^.00 Veea O 12 ? O ' _/ 1,718,000 i / 158 J 27.00 Aldebaran O IO ?/ 1 *^ / Jj7 v * v ' 2 062.26=; o IQI / 72. OO Capella O IO -i- j \ ^ \-/ ^^ j ^i- V-' J 2,062,265 .7 IQI o 72. OO Polaris O O7 2 04.6 64.O y 276 o 47.OO Arcturus . . .O.O2 .'i/T-^'^T^ io,^n,2i;o / Q^O TV I6O.OO This is an impressive display of facts and figures. Thus the nearest star, Alpha Centauri, is brighter than the standard first magnitude Aldebaran, while the next nearest, 61 Cygni, is only of the fifth magnitude, requiring a clear, dark night to see it without a lens. Sirius, the most brilliant star, is just twice as far away as the nearest. Look at the vast distance of the pole star 276 trillion miles and the colossal Arcturus. How approach this majestic sun with human speech? It pours forth 6,200 times the quantity of light emitted by our little sun. Many astronomers have despaired of ever finding its distance, but in very recent years the mighty problem has been attacked with renewed energy, patience and skill, notably by Dr. Elkin. Astronomers are agreed that its parallax is about the one-fiftieth (i-5oth) of a second. That is, go to Arcturus and look this way with the most powerful microm- 226 RADIANT ENERGY. eter made, and the distance from the earth to the sun 93,000,000 miles would occupy one-fiftieth of a second in the sky. Take a child's marble one inch in diameter to a distance of 161 miles, and it will appear to fill one-fiftieth of a second as an arc of a circle. And modern astronomers must measure such quantities as these or remain ignorant of the dimensions of that part of the universe close by home. But the mighty sun Canopus go to it, turn and look this way ; the distance from the earth to the sun is absolutely invisible in any microscope that human hands can ever hope to make. Canopus is brighter than Arcturus ; and a line 93,000,000 miles long, as seen from Canopus, is less than the diameter of a spider's web. But great things are now being done by photographing the heavens, and then measuring the inconceivably small displace- ments of the stellar points with a high-power microscope, under a system of rectangular co-ordinates, also photographed in small squares, like cross-ruled paper. The stars are graphed by a long exposure, and then fine crossed lines are graphed on the same plate by a second exposure, and numbered. Thus any star can be found as well as a house in a city block. The plates are measured under a micro- scope in a measuring engine, and if any displacements are noted in subsequent graphs the amount is determined. Thus parallaxes of the stars are now found by machinery instead of by the old-fashioned, laborious and tedious methods. A most extensive series of measures is now being made at Harvard College Observatory notably by Mrs. Fleming and Miss Maury, the collection of plates now numbering more than 1 10,000. A succession of important results has followed, for proper mo- tions of stars have been discovered, also variables, and new stars as well. The photograph is revolutionizing all departments of practical astronomy, for Professor Pickering and his skilled as- RADIANT ENERGY. 227 sistants at Harvard and Arequipa, graph the entire heavens, once each month ! He superposes subsequent graphs by months, so, if any star has moved, it will be instantly noticed, for their images on the two plates under the microscope will not exactly coincide. Cut 88. Double Cluster in Perseus. Some regions in the sky are rich in stars, and an idea of the power of modern instruments may be had in cut 88, the double cluster in Perseus, where no separate stars appear to the unaided eye. All are familiar with the Seven Stars or Pleiades. With i?h. 3om. exposure on nine (9) nights, a region round about, four 223 RADIANT ENERGY. square degrees in area, shows almost 7,000 stars on the plate. The stars often gather in clusters, as may be seen in cut 88. The Perseid cluster is made up of fine stars many regions in the Milky Way are hundreds of times finer as in cut 89. Cut Cut 89. Photograph of Milky Way, taken at Sydney, Australia. 89 is of a photograph of a rich region of stars in the Milky Way, taken at Sydney, Australia, all of which were condensed and broken up from one mass of primordial, ultra-gaseous corpuscles "bodies much smaller than 'atoms.' " RADIANT ENERGY. 229 XXXIII. BINARY SUNS. "It is thus by an alternative waking and rest, that the immutable Being causes to revive and die eternally all existing creatures, active and inert." From Laws of Manu, book i, Shloka 50, Hindu. Herschel in his life-long and tireless search for stellar parall- axes, not one of which was he ever able to find, owing to his lack of accurate micrometers, and knowledge of the exact value of refraction of light in the earth's air nevertheless made another discovery almost equally important binaries. These are where two suns revolve around their common center of gravity, in regu- lar orbits, nearly always ellipses. And their study has greatly expanded all concepts of the sidereal universe and its ancient history of evolution. So surprising have been the results of this investigation, that modern astronomers are amazed at the work of their own hands, while the ablest now living would have thought them beyond human powers, had they been predicted fifty years ago. The revelations due to binary, triple and multiple suns should be understood by all who admire nature or who care to know what the brain of man is really capable of doing in this age of trained research. As soon as the two Her- schels, Struve and other astronomers found that vast incandescent suns were in revolution around each other, or rather around gravi- tational centers, world-wide interest was at once awakened and many skilled observers began extensive series of most precise meas- urement. RADIANT ENERGY. Cut 90. Binary BC of the triple Sun Gamma Andromeda. Positions From 1842 to 1897. Gamma Andromeda is a triple sun, the largest star being A, the next B, and the faintest C. The star B is shown at B in cut 90, while all the black dots are positions of the star C, meas- ured from 1842 to 1897 55 years. The star A is 10 seconds of arc distant from B, and is not shown in cut 90, for a distance of 10 seconds, small as it is, would be too large to appear in this wondrous diagram, where the length of the scale below is only half a second. A sphere one inch in diameter to subtend half a second must be at a distance of 6~/ 2 miles. The black spots are nearer the mark than rifle shots by an expert. These small errors were not so much in the micrometer as in the earth's air. The network of angles from dot to dot has been solved, and the result is the curved line, I, 3, 2, a very eccentric ellipse, the mathematical orbit of the star C around B, or, strictly, around the center of gravity of B and C, for B also traverses a minute ellipse the same in shape of that moved over by C, once in 55 years. The letter C does not ap- pear, it may be imagined to be anyw T here on the ellipse, i, 3, 2. It will be noticed how eccentric the orbit is, that is, its devia- tion from a circle, which is 0.82, while that of the orbit of the RADIANT ENERGY. 231 earth around the sun is 0.017, only one-fifth as great. The con- sequence is that when the flying sun C moves from I to 2, around B, in the direction of the arrows, it moves with great speed to prevent falling on B, while the velocity is slow at 3, far away. The nearest approach to B is called periastron, while the most remote position is apastron. This binary has just made one circuit since discovery, and five years on another. The two stars B and C do not revolve around A, the large star, 10 seconds away, so far as detected, but they all move in the same direction, side by side, through space, which movement of stars is called proper motion. The star C passed periastron in 1892. It is not necessary to watch a binary through a complete revolution, for, give an arc of an ellipse to a geometer and he can compute the entire curve. And some of the times of revolution are known to be more than 1,000 years. Human beings could not live on the planets revolving around either of these suns, B and C. For when C came near B the inhabitants would be between the suns and there would be no night. All water would be boiled into steam and life expire. As periastron approached, the people on worlds round about sun C would notice sun B growing rapidly larger. And then larger and hotter still, and the heat and light would soon become intol- erable. Milton's concept of living beings chained to incandescent, porphyritic stone, would fail here. The planetary heavens would burn as heated brass, and the heats of Pelee and Souftriere would pale and faint. The surfaces of the inhabited worlds would be- come parched, cracked and seamed steam, smoke and deadly gas would fill the suffocating air. People near sun B would behold C rushing through their torrid sky with frightful speed, growing larger and hotter every minute, and the sinister sun would appear in most portentous 23 2 RADIANT ENERGY. aspect. For a world happening to be between the suns, rapid death would fall on plant, animal and man, or a still higher type. The eventful day of periastron would occur every 55 years. It is doubtful if life can be on worlds about suns whose orbits have eccentricities greater than one-half, for even then, the variation in heat would be tremendous. The distance of the system of Gamma Andromeda is unknown. ALPHA CENTAURI. This majestic pair of suns, our nearest neighbor, revolves in 8 1 years. The eccentricities of their orbits are one-fifth, so, beings with no more intelligence than men might adapt themselves to the great variations of climate. FINDING MASS OF BINARY SUNS. Kepler discovered one of the most stupendous laws that the brain of man has yet detected in the hidden recesses and labyrinths, dim corridors, obscure passages and caves under nature. This law rules all that fraction of the sidereal edifice near enough to be seen in telescopes, however powerful. Law : The squares of the times of revolution of bodies around their common center of gravity are to each other as are the cubes of their mean distances from their center of motion. Application of Law : The time required for the earth to revolve around the center of gravity of the earth and sun is equal to one (i), and the earth's distance from that center equals one (i). The observed time for Jupiter to make circuit is equal to 11.86. Now 11.86 squared is 140; and the cube root of 140 is 5 . 2, but that is the known distance of Jupiter from the sun, found in other ways. That is, Jupiter is 5 . 2 times farther from the sun than the earth is, or 483,000,000 miles. This law enables men to tell the quantity of matter in suns, so far away that the mind is unable to form any concept of the distance. RADIANT ENERGY. 233 A quantity of matter equal to that in the sun and earth com- bined is by the action of gravity able to force a body at the earth's distance from the sun to go around it in 365^4 days to prevent falling into the sun, for the centrifugal tendency equals gravity. Since gravity depends on quantity of matter, or mass, it is clear that there must be a strict relation between the motion of the earth and the sun and between the Alpha Centauri and its revolving sun. The combined mass of these two suns is able to force one of the suns at a distance from the most massive, 21.33 times as great as that of the earth from the sun, to revolve around it in Si years to prevent falling. Then the distance, 21.33 cubed, equals 9,664, while 81 squared is 6,561, and the quotient of these numbers is 1,5, so the quantity of matter in both suns is known to be one and a half times greater than that in our sun and earth. Since the mass of the earth amounts to nothing almost it is said the suns in the Centaur are ij^ times more massive than ours. Their distances apart 21.33 is obtained from the appar- ent semi-major axis of the orbit, which is 16 seconds of arc. This, divided by the parallax, 0.75 of a second, equals 21.33 times 93,000,000 miles, equals 1,984,000,000 miles, a little more than our planet Uranus from our sun. Thus given three quantities the distance to these two suns twenty-five million million miles their distance apart, 21.33 times greater than that of the earth from the sun, and their time of revolution 81 times greater than that of the earth then the finding of their combined mass is a mere question of arithmetic. But it took 120 years' severe labor to find the distance, and it took Kepler 17 years' unheard-of work to find his mighty law. Cut 91 shows the orbit of the binary, Alpha Centauri. THE SUN SIRIUS. About fifty years ago it was found that the regular motion of that, to us, brightest of stars, Sirius, was disturbed. Instead of 234- RADIANT ENERGY. traversing a regular curved line on an ellipse, or a straight line through space, clue to our own proper motion, it deviated first to one side and then to the other. It was watched with interest by many astronomers. They all agreed that the perturbation was caused by either a small sun revolving around it or a dark world. Auwers then applied that mighty power, mathematics, computed the orbit of the unseen body, and told its direction from Sirius. And then A. G. Clark discovered it in exactly the predicted place with his new telescope, now in the observatory at Evanston, Ills. ** t^ ^ 0> ^X^ v^ V- ^^ , ^ ^v t *6^- \ ht ,* * Cut 91 Orbit of Our Nearest Neighbor, Alpha Centauri. Period 81 Years. This was the beginning of that great branch, the "Astronomy of the Invisible." The new body proved to be a small sun, for it shines by its own light, where planets are seen only by borrowed radiance. MASS OF SIRIUS AND ITS COMPANION. For several years the parallax of Sirius, as determined by Professor Gill, has been adopted as 0.37 second of arc ; but now comes W. S. Adams with a spectroscopic parallax of 0.21 second (the mean of these is 0.29 second), and with this let the mass of both suns be computed. A radian 206,265 seconds divided by 0.29 second equals 700,000. That is, Sirius is 700,000 times farther from the earth than our sun is. RADIANT ENERGY. 235 in cut 92 is shown Professor N. M. Mann's carefully com- puted orbit, and its semi-major axis is given by him as seven seconds (Newcomb gives five seconds), which is the apparent value seen from the earth; the real value, being seven, divided by 0.29, equals 24; thus the companion is 24 times farther from Sirius than our sun's companion, the earth, is from it. Kepler to the rescue, for the distance, 24 cubed, is 13,824, and the time, 50 years, squared equals 2,500, the quotient of the two numbers being 5.5, so the quantity of matter in Sirius and its neighbor is Cut 92. Orbit of Sirius. $ l / 2 times that in our sun and earth. If the value, five seconds, as given by Professor Newcomb, had been used, the mass would have come out smaller, for less matter would be required to cause the small sun to make circuit around Sirius at a less distance in the same time. The error is less than those made in shooting at the Harvey- ized steel targets in the navy-yards. Life cou'.d not exist a min- ute on planets around the revolving sun, even when at its mean distance of 1,232,000,000 miles, or less than that of Uranus ii om the sun. There are over 200 telescopic binaries known that is, widely 236 RADIANT ENERGY. separated suns whose distances apart are great enough to be seen in the best telescopes. But new and more magnificent arrays of splendid binary and ternary suns are shown in the spectroscope. Here is a table of short-period telescopic binaries : Periods Names of Suns. in years. Kappa Pegasi 1 1 . 42 Delta Equulei 1 1 .45 883 Burnham 1 5 . 80 XI Sagittarii 18.85 Rho Argus 22.00 85 Pegasi 24.00 From these short periods of revolution, the times extend to as high as 1,500 years. Thus, from Professor W. J. Hussey's cata- logue, Lick Observatory, these periods are taken at random: 135, 200, 115, 118, 93, 182, 190, 107, 260 and 198 years, while the star Zeta Aquarii is 1,500 years. Some astronomers devote their entire life-work to double stars ; thus Professor S. W. Burnham devoted thirty years to this great work and discovered 1,290 close stars, while Professor W. J. Hussey has discovered many and remeasured all those dis- covered by Russian astronomers. Prominent among them are the stars Gamma Andromeda, as shown in cut 90. The maximum distance between the compo- nents was in 1877, 0.84 second. At this writing they are less than half a second, and scarcely visible as two points in the Lowe i6-inch telescope, if at all. The two dots large suns, however of Gamma Andromeda, look like one in anything but a large telescope. And the larger the object-glass and the higher the power of the eye-piece the RADIANT ENERGY. 237 Cut 93. Barnard's Milky Way. wider is the black, infinite space between. This is called separat- ing or magnifying power, but not a solitary star in the celestial vault can be magnified by any instrument men can make ; their distances are so stupendous that they all look like minute points What the telescope does is to bring millions more into view. Planets near home are all magnified into wide discs. Of all telescopic binaries, perhaps sixty orbits have been com- puted with varying degrees of accuracy, measures being as diffi- 238 RADIANT ENERGY. cult as any dealt with by astronomers. But binaries capable of detection by telescope are few indeed compared to the vast num- ber now being discovered by that all-powerful and marvelous in- strument, the tele-spectroscope. Thus space contains countless suns, revolving around their centers of motions with great speed. Many millions of these may be surrounded by cool worlds, each inhabited by beings for more exalted in mental power than the human animalculse. RADIANT ENERGY. 2 39 XXXIV. z. DISCOVERY OF SPECTROSCOPIC BINARIES. "The universe is a unique, perfect and spherical production, since the sphere is the most perfect of figures ; animated and> endowed with reason, since that which is animated and endowed with reason is better than that which is not." Timaeus of Locris. The binaries mentioned in XXXIII were all discovered by means of the telescope, measured with micrometer, and their masses computed by gravitational methods ; that is, by Kepler's laws. But the detection of vast suns revolving- around their mass centers in space at once awakened the keenest interest. These re- condite researches were made with the spectrograph a modified form of spectroscope attached to the greatest telescopes. Their discovery was made possible by an abstruse law of wave motion known as Doppler's principle, by which if a light source comes toward or recedes from the observer, its velocity can be found. Cut 94. Doppler's Effect. A and B are luminous points, emitting waves in the direction S. While waves move from A to S, B moves from X to B. Cleared in cut 94, where A is a source or light at rest. To its right are eight waves moving to S, while B also is a light source, and was formerly at X. Let both waves enter the slit of a spectroscope, S, at the same time. ' While light was moving from A to S the source of waves, B, moved from X to B, over 240 RADIANT ENERGY. space equal to one wave-length. Then, since the velocity of light does not change, it is evident that the light waves will be crowded into the space properly occupied by seven normal undu- lations. That is, each will be one-eighth shorter. This is a bed- rock fact in nature, and leads to the most wonderful deductions. All along in this series it has been shown that the shorter the waves the greater is their refrangibility, or property of being bent aside out of their course by refraction of a prism or diffraction of a grating. Violet is bent the most and red the least, for violet vibrates nearly twice as fast as red, therefore its waves are slightly more than half as long as red. Whence the fact stands out that the place of a color, or if this is absorbed, a line, in the spectrum is determined solely by its wave-length. Cut 95. White I^ight (Fig. 1) Passing through a prism, P. Fig. 2 Resulting displace- ment spectrum shown in dotted lines. This is cleared in cut 95, where white light is entering a prism as a band and emerging as a wide spectrum, the violet being deflected aside the most, in figure I. Basic Law : If a source of light is approaching, the lines in its spectrum are displaced toward the violet; if receding, the lines shift toward the red. With breathless interest let the powerful spectroscope be turned full on the stars, and see what will appear! Behold ! The spectra of many stars actually show displace- RADIANT ENERGY. 24.1 ment, now toward V, and then to R, as shown by the dotted lines in figure 2, cut 95. Human skill is taxed to the utmost in these delicate re- searches. The slit of the spectrograph is exceedingly minute, and the great driving clock moving the giant telescope must keep up with the rotation of the earth with extreme accuracy. The entire Cut 96. The Mills' Spectrograph in the lyick Observatory cover off. spectrograph must be kept at the same temperature throughout the long exposure of the sensitive plate. This is accomplished by inclosing the entire instrument in a non-conducting envelope and keeping the interior at a constant temperature by means of electric resistance coils. All this is shown in cut 96, the now famous Mills spectro- graph in the Lick Observatory. 242 RADIANT ENERGY. Cut 96A. Mills' Spectrograph, enclosed in constant temperature case. Professor W. W. Campbell, with this instrument, has wrested the most reluctant secrets from the universe and told the motion of suns, brought unknown binaries and distant systems of suns in revolution to the gaze of astonished man. The complex mechan- ism in the upper and right hand part of cut 96 is the end of the 36- inch equatorial. The Spectrograph is inclosed in thick woolen cloth. The box is of cedar, and its cover is seen on the floor. The little tube is the guiding telescope to center the apparatus, and looks down on the train of prisms ; while above is a window through which the micro-thermometer, sensitive to one-twenty- RADIANT ENERGY. 2 43 Cut 96B. Mills' Spectrograph without case. fifth degree, is read. The great object-glass 36-inch far above, receives lights from suns, sends it through the tiny slit, one-thou- sandth of an inch wide, and prisms to the spectro-camera, where the wondrous graphs are secured, telegrams from suns so distant that the mighty void between cannot be measured. Cut 966 is the Mills-graph before the case for regulating temperature was added. There are other spectrographs in the world, notably that of Vogel, in Potsdam, Germany, but none have dragged forth mys- teries more arcane than the Mills graph. 244- RADIANT ENERGY. MOTION OF STARS IN THE LINE OF SIGHT. Many suns are thus seen to be approaching, and as many re- ceding with varying speeds, all rapid. The star must approach or recede on a straight line for motion to be detected, for side- wise motion cannot be seen in a spectroscope, since it does not change wave lengths. Doppler's law can be proved by any one who will stand by a railway when an express is coming, if the bell or whistle sounds. If approaching, the key note rises, for more waves enter the ear, while after the train passes, the note falls. Approaching. Receding. Miles per second. Miles per second. Alpha Arietis 12 Aldebaran 31 Gamma Leonis 25 Betelgeuse 18 Spica ii Rigel 14 Altair 24 Capella 30 Polaris 12 Alpha Coronae 20 61 Cygni 27 Regnlus . Procyon 7 Eta Pegasi 3 Arcturus 5 XI Piscium 19 Beta Herculis 30 Epsilon Hydrse 30 Sirius 5 In cases of binaries moving in the line of sight the motions given are those of the center of mass, around which both revolve. Combining quite a number of cases, and taking their mean, it appears that the velocity potential to or from the earth is about 16 miles per second, the speed of the earth on its orbit being 18^2 miles per second. Below is a table giving periods of revolutions of binaries, discovered by means of the spectro- scope, together with their orbital velocity in miles per second. RADIANT HNHRGY. SPECTROSCOPIC BINARIES. 24-5 Orbital Velocities Periods. Miles per Names Days. Second. Mu Scorpii 1-45 144.0 Pi Scorpii I S7 L ' j/ Delta Orionis 1-91 44-5 Beta Persei 2.87 25-8 Castor (i) 2.91 7.0 A. G. C., 10,534 3-I 2 190.0 Beta Aurigse 3.98 75-o Pole Star 3-98 2.O Spica 4.01 57-o Delta Cephei 5.37 13.0 Eta Aquilse 7.18 13-4 Zeta Centauri 8 02 Zeta Geminorium 14-15 8.2 Iota Pegasi IO.20 30.0 Beta Lyrse 12.91 113.0 Xi Leonis H-IS 35-0 Lambda Andromeda 20 . OO 5-o Capella . . . . IO4.00 16.0 Beta Herculis .... 412.00 8.0 Chi Draconis 282 . oo II. Eta Pegasi 8l8.00 9.0 Beta Canricorni . T.OOO.OO This is a remarkable range in time and velocity, from 45 hours to three years, and from two to 190 miles per second. So vast is the distance of Polaris that an error is easily made in bringing out its speed only two miles. 246 RADIANT HNHRGY. Not one of these stars would ever have been known as bina- ries without the spectroscope, for no telescope could be made to see them double (they look like a point) with any magnifying power. And their spectra are all photographed, so that in the future, should changes occur, they will be seen. +++++++++++++++++* CUT 97 ORBIT OF A BINARY SUN HIGHLY ECCENTRIC. DETECTION OF BINARIES. Call A and B two suns, so close that no telescope could sepa- rate them; but let them actually be revolving as shown in the orbit, cut 97. When the sun of less mass is at A it is re- ceding from the earth, and approaching with greatly increased speed when it moves around in the direction of the arrows to 13. The lines of sight to the earlh are parallel as shown, no matter how large the orbit of any binary yet discovered may be. And waves on these lines enter the spectroscope on the dust particle called the earth, as at S, cut 94, and displacement is measured. And the velocity of approach or recession can be computed by mathematical formulas or- determined by experiment. VELOCITIES AND DISPLACEMENT. In cut 98 let S be the sun and E the earth, while A and B represent the planet Venus at opposite points on its orbit. At A the planet is receding from the earth on a straight line, while at B it is approaching. But the velocities of Venus at these points RAD I A NT ENERGY. 247 are known with great accuracy, so the value of displacement of spectral lines becomes known. If an observer on an express train, at one mile per mTnute, travels toward the star Vega for 100,000,000 years, and takes a powerful telescope the largest made and a spectrograph, and should turn and look this way, straining his eyes, he would see a faint and struggling ray from our sun. With consummate skill he might secure a spectrogram showing displacement. If he did, he would find the shifting toward the violet, and computing would find the sun approaching with a velocity of twelve miles Cut 98. The Sun, S; E, the Earth; A and B, Positions of the Planet Venus. per second. For our little star the sun is moving toward the giant Vega, and drags along its stately company of planets, moons and comets. Our star is not a binary ; it is solitary and alone in space. A ship in the center of the Pacific ocean is not more lonely. Indeed, not at all, for her crew can speak with human kind on any distant shore by space waves soon. For some on land know that such a ship exists; but if the 5i,(ereal universe is filled with intelligent beings, only professional astronomers have heard of the sun, and none are aware that the earth is in exist- ence. RADIANT ENERGY. Cut 99. Spectrum of Beta Aurigse. Upper Figure showing Displacement of a I^ine. In cut 99 is shown a marvelous spectrogram of the binary sun, Beta Aurigse, where two suns make revolution in four days, with velocity of seventy-five miles per second. But what shall be said of Mu Scorpii, two suns rushing with a terrific speed of 144 miles per second, making circuit in forty-five hours? RADIANT ENERGY. 249 XXXV. SPECTROSCOPIC BINARIES. O Thou of whom all is the manifestation, Thy nature is the spring of thy being: Whatever is, is thou ; We are all billows in the ocean of thy being; We are a small compass Of thy manifested nature. From Dabistan, Vedantic Phil., Hindu. Since the evolution of the human species began, or since spoken or written language developed, or since man began to think, since he first questioned nature, and through all of his devious and erratic career, whether within the historic period or before, all achievements wrought by his hands fall short of the marvelous work recorded in this chapter. This great achievement of the brain of man beyond comparison with anything else, start- ling even to the men who do the work, is the vast problem lately solved of finding the masses of suns without knowing their dis- tance. In chapter thirty-four, the quantity of matter in suns was computed by well-known laws of mechanics, for in every case the distances from the earth to these distant suns were given. But by spectroscopic researches on waves of light, fully explained under the title "Doppler Effect" a plan was discovered that bor- ders one would think on the limit of human powers. 250 RADIANT ENERGY. Cut 100 shows compressed and expanded waves from a binary sun. The eye of the reader should be imagined to be in the plane of the paper looking toward S. Cleared in cut 100, where S is a large sun with a smaller sun making regular revolutions around it on an orbit of great eccentricity. A line extends from S in the direction of the earth, which in the cut is marked distant 100 trillion miles. It could as well have been 200, since distance has nothing to do with the problem, pro- COMPRESSED TO THE EARTK 100 TRILLION" HUES I A WAVES Cut 100. Orbit of a Star around S. Waves that reach the earth are compressed and lengthened, viding sufficient light can pass through the space, whatever i- may be, to form a measurable spectrum. At A the revolving sun is retiring from the earth, and waves of light since neither rates of vibration nor velocity of propagation change must become longer, and a less number enter the spectroscope each second; and become shorter at B, and more pass into the slit. In Chapter thirty-four, cuts are given showing that this change in wave- RADIANT ENERGY. 251 lengths produces lateral shift of lines, now toward the red, and then toward the violet, and speeds of approach and recession corresponding to lateral displacements are known, which knowl- edge leads to surprising results. HOW TO WEIGH BOTH SUNS. It will be understood that cut 100 is a spectroscopic binary, that is, the smaller sun whether at A or B cannot be seen in any telescope, both suns look like one, even in the 4O-inch glass. Their real distance apart may be many million miles, yet so stu- pendous is the distance from the earth that they look like one. But the spectroscope deals with waves requiring 64,000 to make one inch, and can detect variations in velocity of the flying sun where the telescope -alone would be powerless. Neither can the spectroscope see the revolving sun, whether at A or B, all that appears in any spectroscope is the band of colors called the spec- trum. All that it does see in this case, is the change wrought in lengths of light waves at A and B. But this is enough to enable mathematicians to compute the quantity of matter in both. The curve around the large sun (S) is an ellipse, whose properties are known with rigid accuracy. B is the periastron, and A apas- tron, and velocities at each are measured. At A the speed is slow, while at I> it is so enormous as to be past comprehension. But, with both velocities, it is possible to determine the average velocity all the way round. And by watching, the time of revolu- tion can be ascertained. A train moving 6 hours with a speed of 50 miles per hour travels 300 miles. And a sun whether on an ellipse or circle, moving 50 years with a velocity of 40 miles per second, describes a distance de- termined by simple multiplication. Thus the great fact now ap- pears. 252 RADIANT BNBRGY. THE SIZE OF THE ORBIT IS KNOWN. From Kepler's Law see chapter XXXIII, it is known how much matter is required acting- by gravity, through any given distance, to impart any given velocity, to prevent the two suns from falling together. And thus human genius has found the masses of binary suns sunk in unfathomable depths, so deep that no micrometer can give any clue to the distance. Thus since man appeared, no instrument, no concept, no achievement, can com- pare with this mighty work. BETA I.YRAE. This massive binary presents phenomena of great interest to the spectro-physicist. Bright lines are seen in its spectrum, and dark lines at times are superposed either over them or closely side by side. But the bright and black lines oscillate now to the right and now to the left toward the red and to the violet. Most accurate photometers are now in use. They measure minute variations in the intensity of light of variable stars, and a majority of binaries sent out variable quantities of light. The 3.6 mg. star Beta Lyrae, near the bright star Vega now glorious in its radiant splendor, rising early these June evenings in the northeast is variable. Watching closely, the light is seen to decrease to a minimum in six and one-half days, and then the intensity begins to rise ; but by looking carefully with micro-photometer at the time of next minimum, it will be noticed that the light is not the same as in the first minimum. But maxima are equal. Here was a surprising case, unequal minima and equal maxima. Renewed observations were made by the ablest astronomers, and none could find the cause, until Professor G. W. Meyers came to the rescue. RADIANT ENERGY. 2 53 The remarkable system of Beta Lyrge is made clear by Meyers' demonstration in cut 101. Not being aware that Profes- sor Myers has printed any cut, this one is drawn to represent the phenomena as described by him, using Poincare's apioid form of sun. The apioid will be explained in the next paper. In cut 101, a and b are two suns, distorted in shape by centrifugal tendency due to rapid revolution, a complete circuit is made in 13 days, Cut 101. Meyer's Conception of the Evolution of the Binary, Beta Lyrae. and by Darwin's tides. Let the small sun, b, approach the reader's eye, and a, recede, below the plane of the paper, both revolving around their center of mass, c. The side view as seen from the earth presents the maximum light, for both a and b are visible, as one star, however, their distance from the earth is so great as to forever preclude their ever being seen separated. But the spectroscope measures their radiant waves. As they turn, b will come betwen the observer's eye and a. The small sun is two and one-half times as bright as the large. The combined light of both stars will enter the spectroscope on the same straight line, and the result is the bright minimum, as shown at c in the two con- centric circles below b. When b revolves so as to be behind a, as shown in the dotted circle d, the light of a only will be seen, and the result is, a dim minimum alternating every 6^ days. If both suns are^ ellipsoids. 254 RADIANT ENERGY. Cut 102. Dr. Vogel's Visual Telescope A and Photographic Telescope B and Spectrograph, 2. Potsdam, Germany. RADIANT ENERGY. 255 ovals but of different sizes and brilliancy, results would be the same, as in the pear-shaped sun here given. Period of revolution around mass center, 13 days. Distance between centers of suns, 30,000,000 miles. Mass of small sun, greater than our sun, 9 times. Mass of large sun, greater than our sun, 18 times. Density of both suns is less than that of air. Velocity on orbit, no miles per second. Distance from the earth unknown, and immeasurable! But the mass is known, and the chief work of human hands wrought mass without distance. The mystery is, how a sun of such low density can be hot enough to send light to such incredible distances as the earth. However, electricity may be in activity in this phase of matter. Such intricate problems are beset with chances for mistakes, for if errors of a few liundred-millionths of an inch are made in measuring displacements of lines, the result will be vitiated by corresponding errors. The values here given for Beta Lyne are those of Vogel, de- termined with his new spectrograph lately installed in Potsdam, as shown in cut 102. At A is shown the end of the great visual telescope, and B is the graphic telescope, for waves that affect the retina of the eye will not affect silver salts to make good graphs. So the objectives have different focal lengths. At I is shown the case inclosing the train of prisms. These analyze faint stellar light, separate the waves and form a displacement spec- trum on the sensitive plate at 2, where it is graphed for meas- urement of its lines under a microscope. Cut 103 is the interior of the spectrograph, showing three prisms at i, and the plate at 2. At 3 is an opening in front of the slit S, where may be placed a Geissler hydrogen tube, flashed by electricity, so that its light can enter the slit with that from the star, for comparison. Since the lines are side by side, either from a reced- 2 5 6 RADIANT ENERGY. ing or approaching star, with those from the incandescent hydro- gen, lateral shift can be measured with accuracy by micrometer. Or, if iron or magnesium are prominent in the star, two ter- minals of these metals are attached to the poles of a high pressure Cut 103. Interior of Dr. Vogel's Spectrograph. induction coil, and are flashed, when the heat turns the ends of the metals to incandescent gas, which also sends vivid light into the slit for measurement alongside of the same metals white hot in the distant stars. Dr. Vogel has already made many discoveries in the motion of stars in the line of sight. RADIANT ENERGY. POIvARIS. In 1899 Professor W. W. Campbell discovered the polar star to be a spectroscopic binary with a period of revolution of 3d. 23!!. 15111. around the center of mass of itself and an invisible companion. But this center of gravity was found to be itself in motion with a variable velocity, therefore disturbed by a third and also invisible body. Thus two suns are revolving, and a dark world like the earth or Mars is making circuit around them. Hartman's recent researches indicate for the dark planet a period of fifteen years, and Campbell gives its speed as about two miles per second, at a distance from the center of gravity of the two suns of 300,000,000 miles. Computing, the combined mass appears to be closely one-sixth of our sun. CAPEI,I,A. This magnificent sun was discovered to be a spectroscopic biliary by Professor Campbell in 1899. Its periodic time of revo- lution is 104 days, with a speed of eighteen miles per second ; while its mass, according to Professor Newcomb, is ten times greater than that of our sun. Thus a majestic and new branch of sideral astronomy is being rapidly developed. New and improved meth- ods of computing orbits are also in evolution, notably by H. N. Russel. And it seems likely to come out that parallaxes of stars will be determined with accuracy in the spectrograph that are so far away that the telescope alone will be forever unequal to the task. Doubtless all the physically connected double stars aie bina- ries, that is in revolution to prevent collapse and collision. Knowledge of the universe is now being immensely extended in the discovery of gigantic suns in rapid revolution with periods ranging from a few hours to many years. 258 RADIANT ENERGY. XXXVI. STELLAR EVOLUTION. "The substance of the heavens and of the stars is called ether: not that it is composed of flame, as pretended by some who have not considered its nature, which is very different from that of fire, but it is so called because it has an eternal circular motion, being a divine and incorruptible element, altogether different from the other four." Aristotle, "Letter to Alexander." "Amongst the stars that are visible move others that are invisible, to which in consequence we are unable to gives any names. These latter often fall to the earth and take fire like that star-stone which fell all on fire near /Egos Potamos." Diogenes of Apollonius. It fell to the lot of two men to change the current of human thought for all time. Charles Darwin established on immova- ble rock the sublime doctrine of evolution among living things. And his not less illustrious son, George H. Darwin, has for all coming ages rooted and grounded the profound doctrine of evolu- tion in all inorganic matter, extending to the confines of the sidereal universe. The most profound and abstruse mathematics that has yet evolved in the human brain has been employed in these elaborate researches. This gave the earth's place so now the evolution of all animate and inanimate things can be traced. The chief product of intellect, since man appeared, is primordial cosmical evolution. The brain of George H. Darwin was the first to see that the surging of tides in ancient liquid or gaseous suns did RADIANT ENERGY. 259 more work in the development of stellar systems than any other agency. As often happens, two minds on earth became impressed with a great truth at the same time. Dr. T. J. J. See saw tfos basic law very soon after Darwin, as an independent discovery, not knowing that Darwin had also seen the great light. The case was similar to that of Le Verrier and Adams, who both computed the mass of Neptune before the eye of man had looked upon it. For mathematics 'has clearer vision than the eye. D B Cut 104. An Ellipsoid. Cut 104 is an ellipsoid. Suppose a gaseous or liquid sun should assume this form, or any other ellipsoidal form by revolv- ing around the long axis AC or the short, DB, then will the deviation from a sphere depend on its speed of rotation and in- ternal viscosity. Thus the earth is an oblate ellipsoid revolving around its short axis DB. Since its ellipticity is slight, it must have been in its consistency, quite viscid when its crust was formed. In cut 105 let two spheroidal suns a and b come within each other's neighborhood in their random flight in early stages of evolution for all suns fly at random now. Let these two plastic suns pass by forever, on the lines shown, then when at the nearest approach their gravity will act upon each other. But that attraction changes their entire subse- quent career. Let one or both suns be in rotation on either axis with any velocity. Gravity of each will produce distortion on the mobile mass of the other; and draw it out of the regular geo- metrical form. But centrifugal tendency of rotation still acts 260 RADIANT ENERGY. on the changed shape and produces most remarkable and far- reaching results. Each mass will leave its original path, no longer traverse the dotted lines, but make a graceful bow or nod to each and recede forever on a hyperbola for a track. But each sun will be broken into two suns. Let sun b evolute itself, and direct at- tention to a, where it is seen drawn into a new shape by the at- tractions of b, as shown in the dotted curve, or pear-shaped mass. When Darwin and See were casting plumb lines over the Cut 105. Plastic Suns passing, nearer to return. sidereal structure, the French geometer, Poincare, sunk a sounding line into the fathomless sea of space. He found an equation calling for an entirely new geometrical form totally un- known to mathematicians, and of course not known to La Place when he formulated his famous and now superseded hypothesis of the formation of worlds by the abandonment of peripheral rings by rotating and subsiding gaseous or liquid masses. Cut 1 06 is Poincare's all-important apioid, through which form many binary suns are now known to be passing. The apioid is based on rigorous mathematical formulas, which he elaborated. LAW : Where there is a mathematical, there is also a physi- cal possibility. RADIANT ENERGY. 261 Could the brain of that great mathematician, La Place, now become reanimate, its genius would doubtless at once give up mainly the ring doctrine of stellar evolution. It is possible that a nebula may break up into rings by action of other masses and its own tenuity and internal state, but that is not the leading fact in nature. Cut 106. Poincare's Apioid. GEMMATION. Here is encountered a mighty law that seemingly holds the whole of nature in its grasp, reaching from a minute living amoeba to white-hot sun. In cut 107 is shown the process of gemma- tion of an apoid sun to form two. Figure I is the regular Cut 107. An Apioid Sun dividing into two. geometric apioid rotating in the direction of the arrows. In figure 2 contraction is more pronounced, while in figure 3 the segmenta- tion is well advanced, and the wondrous work is complete in 4, when two suns are formed, both rotating in the same direction of the original cosmical mass. Each sun may be gaseous or liquid 262 RADIANT ENERGY. and from one million to a thousand million miles in diameter, ac- cording to their constitution, whether liquid or gas. This is a phase of evolution of inanimate matter. But all living matter makes identical evolution. Cut 108. An Amoeba making Segmentation. Cut 1 08 is that of one amoeba making reproduction by gem- mation, and all animals, from amoeba through all protozoans, ra- diates, mollusks, articulates and vertebrates to man, are simply congeries of cells. Cut 109. The Sun V Puppis in Process of Gemmation. The ligament is about to be severed. The binary sun named V Puppis, from a discussion of all ob- servations by A. W. Roberts, will satisfy equations based on spec- troscopic determinations, by the mathematical figure in cut 109, where light still lingers in the band not yet torn asunder in the forming suns. These giant suns make revolution in one day ten hours and fifty-four minutes, and their density is only one-fifth that of our sun. RADIANT HN HRGY. 263 XXXVII. EVOLUTION WROUGHT BY TIDES. "The lovely Dawn, arousing man, goes before the sun preparing practicable paths, riding in a spacious chariot; expanding everywhere she diffuses light at the commencement of the day." "Harnessing the purple oxen to her car, unwearied she renders riches perpetual; a goddess praised of many, and cherished by all, she shines manifesting paths that lead to good." Rig Veda Sanhita, Vol. HI, p. 369- The computation of the action of primeval tides on form- ing worlds and suns involved a grade of mathematics much more complex than the formulas employed in the discovery of the loca- tion and mass of Neptune before the eye of man had seen it. George H. Darwin first gave tidal formulas to the scientific world and aroused the supreme admiration of all who heard the won- drous story. PRIMEVAL TIDES. Darwin's mathematics looked on primeval chaos, where lens and plate are useless. He began his history of evolution with the ancient earth and its moon, but the reasoning applies to the development of binary suns as well. Tides began the next day after the moon separated by gemmation from the equator of the earth ; neither had time to assume the spherical form before tidal force clutched both. Tides formed the earth and moon. 264. RADIANT ENERGY. FIRST DAY. The first day began at the instant the umbilical cord leading from the viscous earth to her daughter the moon was severed, and ended when the point of rupture came round to the same place again. The first month began at the instant of the moon's birth and ended when it also came to the same point after one circuit around the primitive earth. Both day and month have from that time been in constant change in length ; they are both changing now no two of either being precisely of the same duration. The first day and first month were very nearly equal, and the length of each somewhere between three and five hours. Not exactly equal, for then there would not have been tidal friction the worker that made both day and month for the same face of the moon would have forever been turned toward the earth and the same point on the earth toward the moon. There would have been one high tide on the earth under the moon, and on the moon op- posite, but no friction, so both worlds would be held by gravity, as if joined by a rigid rod of steel, and hence no friction, and both month and day would have remained between the mathematical limits of three and five hours. The difference, no matter how slight, between the early months and early days was no doubt caused by the disturbance of rupture, but if any variation what- ever occurred, then tidal friction formed the earth-moon system as it now exists. FRICTION DUE TO TIDES. A tide in water is known to have friction within its mass. A tide in oil, tar, honey, liquid steel or melted rocks would cause far more internal friction than tides in water, alcohol or gasoline. The action of tidal friction is as universal as the law of gravity, heat or electricity, and its discovery and mathematical development takes rank with the discovery of gravity and its Newtonian law. The reader is referred to XXXVI for cuts showing the ancient apioidal earth and the separation of the moon mass. RADIANT ENERGY. 265 HOW TIDES PLACED THE MOON ON ITS PRESENT ORBIT. The mechanics of tides and tidal friction may be seen in cut no, adapted to the purposes of this note from both Dr. See and Professor G. H. Darwin, omitting all technical and mathematical portions. Figure a shows a circle and an ellipse, or a sphere and an ellipsoid. The sphere represents the form of the earth if sunk in space far away from any attracting body; really the earth has never been a true sphere. The ellipsoid represents the shape of the semi-liquid or plastic earth, with tides at T and t, caused by CUT 110 Showing the mechanics of tides arid trtial friction. the moon at m. If the day and month had been at that time equal in length, the tides would always have remained as at T and t on a straight line with the centers of the earth and moon, until it cooled and a solid crust formed, so the earth would now be an el- lipsoid. If the day and month were of unequal length, and the substance of the earth absolutely without friction, then the centers of the earth and tides would have been on the same right line; but this is impossible, for even hydrogen has friction within. EFFECT OF FRICTION. But the early days were shorter than the month, and the viscidity of the earth's mass had more friction than a water world. The effect was most important and is now known to be at least one riddle of the universe. 266 RADIANT HN HRGY. Let figure a represent noon of the first day, or morning, or evening, and figure b the same time on the next day. But the day was shorter than the month that is, the earth rotated on its axis faster than the moon revolved in its orbit. This would have no effect in the absence of internal friction, but friction was pres- ent, the tide wave was retarded, could not keep straight below the moon, so the more rapid earth carried it by the line joining the centers of the earth and moon, as shown by cut no, figure b, where the dotted line T, t, is the axis of the tide next day, and has been from that archaic time and must ever be until the earth becomes throughout more rigid than steel, and the oceans solid ice. In figure b the moon is around to m again at the end of the month, but tide T is always in advance of the place it would have been had friction failed, and is now. MECHANICS OF TIDES. ACTION EQUAL TO REACTION. Tide T is nearer the moon than t, hence the attraction of the moon on T is stronger than on t. The pull of the moon on the gravity rope on T tends to pull back T, to bring the doted line T-t into its original line m-c, while the weaker attraction, m-t, tends to counteract it and make the earth turn faster, but m-T is the strongest and must prevail. So the earth is actually slowing down its rotary speed now, the day is growing longer, and even during all that time since the first day. The mass in tide T reacts and pulls on the moon and tends all the time to make it go faster on its orbit in the direction of the arrows. The pull t-m tends to retard the moon, but T-m is more potent, it acts with greater intensity on the moon and tends to increase its speed and, therefore, make the month shorter. One on first reading would think, of course, that the month was in these early times growing shorter, but such evidently was not the case, for it is twenty-seven and one-third days long now, and less than five hours in length then. RADIANT BNBRGY. 267 The instant the moon is accelerated a mighty reaction cen- trifugal tendency lays hold upon it. This terrific power is not an inherent property of matter, but merely a reaction against original inertia common to matter in every form. Tie a cord to a stone, whirl it around, the string pulls ; double the velocity and the pull increases four times, that is, this reaction is enormous it varies as the square of the velocity, as observed in bursting grindstones. A solid wheel of steel will fly to pieces if turned fast enough. As soon therefore as the chaotic moon was accelerated cen- trifugal tendency threw it away farther from the earth into a longer orbit. It required more time to make a revolution. Thus, incredible as it may seem, tidal friction pushed the moon away from the earth and made the month longer. The united chaotic earth and moon revolved on an axis before the moon made escape by segmentation, so the term "first day" above means the first time the earth made one rotation separate from the moon. Had it not rotated before, then a furrow or fissure would not have formed owing to absence of centrifugal tendency in the apioidal mass. Not only the past of the earth and moon can be traced, but the future. The revelations made by Darwin are more astounding than any ever presented. 268 RADIANT ENERGY. GEORGE H. DARWIN RADIANT ENERGY. 269 XXXVIII. EVOLUTION OF THE EARTH AND MOON. The sun remains immovable, and the earth moves round it in a circular curve, of which that star is a center. Aristarchus of Samos. THE: FIRST MONTH. Given a difference between the length of the first day and first month, however slight, even to a minute fraction of a second, then the present state of the earth and moon was inevitable. The entire mechanical work has been wrought by mutual tides. The agency heat has been escaping since, and the less the heat in both earth and moon the thicker the consistency of both masses, the lower the tides in both on account of increased friction, and the less the distance the moon must recede before it turns and begins its long period of winding on a spiral back to the earth. This question of how tides forced the moon away from the earth must be understood, for it is a fundamental law in nature. Tidal fric- tion has done more work than all other agencies combined in the formation of planetary systems where worlds revolve around suns. It is the giant now at work building up binary, ternary and multiple suns, at present seen in active evolution in every direc- tion in space. In fact, it is the great worker of the universe, being the only method by which the primal power, gravity, can get worlds in its clutch to hurl them upon orbits. It separates 270 RADIANT ENERGY. matter in the shape of crude chaotic masses, so the heat of the central mass shall not be too intense to destroy life on later re- volving planets. Tides made our earth and moon. Friction due to tides completely accounts for the evolution of the sidereal uni- verse. The vast subject must be understood by all who wish to know about the immense cosmical structure so overwhelming in its majesty and splendor. A book is required to treat this great new deduction of the human mind ; so only elementary principles will be presumed upon here, not even daring to go near where Darwin is but once, and that to touch the "hem of his garment." This is the absolute beginning of evolution of moons in place around planets, planets and moons around suns, suns and planets around other suns, and underlies the substructure of all stellar systems. If acceleration is understood the outlines of that stu- pendous machine, the universe, will be seen emerging from the most archaic obscurity like the coming of a ship from the mists of the sea. a. 6- CUT 112. Composition of two forces into one. The forces ac and ab are united into ad, all moving \n direction of the arrow?. ACCELERATION. The mystery of acceleration is cleared in cut 112, which shows first, the basic law of mechanics, the composition of forces. Let a mass be at a, and at rest. Let a force act upon it in the direction a, c, with an impulse able to cause it to move from a to c in one second. At precisely the same instant let another force act upon a with an intensity able to send it to b in two seconds. It will not move either to c or b, but will arrive at d. RADIANT ENERGY. The path a, d is always the diagonal of a parallelogram, if the forces are unequal ; of a square if equal. Any number of simulta- neous forces can be compounded into one. This law had to do with the evolution of all solar systems. The composition of forces gravity and friction on the primordial moon, reveals the hid- den mystery why it left the earth. Cut 113. Tides separating the Earth and Moon. In cut 113, e is the ancient viscid earth, and m the chaotic moon, both in the grasp of gravity and in the clutch of tides. In cut no, chapter XXXVII, the moon is shown acting on the earth, and in cut 113 the earth is acting on the moon; they shall be compared. In cut 113 e is the ellipsoidal earth drawn away from the dotted circle by the moon. The tide at v accel- erates the moon on its orbit ab towards b. If, when the moon arrived at m, the earth were suddenly annihilated the moon would move on the tangent to its orbit, t. If the mass of the earth as suddenly increased, the moon would move toward v. If no change occurs, the moon will keep on its orbit to b. But the heaping up of matter at v has somewhat the effect of increasing the quantity of matter in the earth, because it brings some of it nearer to the moon and thrusts other portions away, as at x, that of v pulling with greater force on the line v m than if v were sunk within the dotted circle below. But at the instant the speed of the moon is increased, the mighty centrifugal tendency asserts its sway and hurls it off the orbit ab and sets the moon upon its new track ao, farther away from the earth. And this is why the moon 2J2 RADIANT ENERGY. is 240,000 miles away from the earth instead of almost in con- tact, and why the length of the month is 27 1-3 days instead of scarcely more than one. The only reason why high tides developed at v and x, was because of friction in the viscous earth ; for with- out friction tide v would have been exactly under the moon, and tide x opposite, the day and month being always equal and the surfaces of the moon and earth almost coinciding. At the end of the first month, if it was any longer than the first day by any time whatever, and if the earth's mass had friction by any amount however minute, then the present earth and moon, and the present day and month were inevitable. For at the end of the first month the moon is again at m, but still farther from the earth and will traverse an orbit slightly outside of ao, and so on for each month, perpetually expanding its orbit like unwinding a closely wound coil or flat disc of tape. It will continue to un- wind so long as tides exist, either on the surface or within the earth, the longest month being when the last tide on earth shall die away into rigidity. It will be noticed that at the moon's orbit each new path described at the beginning of every new month is the diagonal of a new parallelogram, as in cuts 112 and 113. FUTURE OF THE EARTH AND MOON. It is shown in the history of tidal evolution that if the first month had been shorter than the first day, the moon must have fallen back on the earth after the rupture of the ligament, if, in- deed, such disruption could have taken place by the action of the earth and moon without the aid of the tides caused by the sun. However, the first month was longer than the first day, else the earth would not have a moon now. These results must follow : The length of the first day and month was somewhere between three and five hours; mathematics could compute the true time if accurate data could be had in chaotic states of the earth-moon. I kit it is a stupendous achievement to know that it falls within set limits. If either three, four or five hours, the truth of the doc- RADIANT ENERGY. 273 trine of tidal evolution is not effected. The month is now 27 1-3 times longer than the day. But friction of tides has increased, is now increasing, and will continue to lengthen both day and month until they become equal, at which time each will be fifty-five of our present days in length. It will take the earth fifty-five times longer to make one turn on its axis than now, and the moon very nearly twice as long to make one circuit around the earth than at present. They will then be as firmly fixed in relation to each other as though joined to the ends of a bar of steel. If, when so clutched as in the jaws of a mighty vise, the moon is central over the United States there it will remain. The moon is clutched by the earth now, and always presents the same face this way. It is only a question of time when the earth will obey the moon's gravity and turn the same face to it. They will still revolve around their center of mass, as may be seen by attaching two unequal balls to a rod, suspending by a cord at their gravity center and turning. The earth and moon will still revolve around the sun, and the earth will have 271/2 times longer day than now and night also, if the sun is shining then, if not, one perpetual night with moon invisible. But in all probability the sun will be dead. Thus when lunar evolution began the day and month differed, necessarily, by only a fraction of a second, and when evolution ends the day and month will again be equal the first day being between three and five hours long and the last 1,320 hours (fifty- five days). The greatest number of days in a month was twenty- nine, and, as there are now 27 1-3, evolution is slightly more than half through with its career. Therefore, the least number of days in a month, the first and last, is one; the greatest twenty-nine. Matters are different on our neighbor Mars, for its satellite Phobos counts off more than three months every day of Mars ; rises in the west, passes through all its phases in plain view of the Martians, each phase being less than two hours in duration. The sum and substance of the evolution of moon and planet from primitive 2 74 . RADIANT ENERGY. apioidal shape is that the first month of the detached moon shall be, any time whatever, longer than the first day. The same is true of binary suns. For if the month is longer than the day all parts of the earth pass in review before the moon, if not there would be no tides. And tides would be useless in absence of in- ternal friction. So the cause of evolution of moons and planets and of binary suns is TIDAL FRICTION. Darwin's rigid analysis surely points to the fact that the final state of the earth and moon will be one of stable equilibrium. No fact in nature is better authenticated. The first state was un- stable, else the earth would not have a satellite now. The sole cause of unstability was friction in tides. In the terminal state there will be no tides, for the earth will be as solid as the moon is at present. The earth and moon will be in deadlock and escape impossible. The term "last day" above is the day on which the sun sends its last wave of light to the earth and moon. Both will still revolve around their center of gravity in a period now called fifty-five days, in night that knows no dawn. Long before this all life will vanish from earth, but if Byron's last man could be on the equator, his only method of finding if the earth turned would be to watch the stars younger than our star the sun. To him the moon would be unknown as well as the sun. The revolution will continue, the earth and moon still casting lifeless periods of time into past duration, while both will revolve on melancholy pathways around a frigid sun, recording useless times called years. Matter in which life is able to exist separates with exceeding ease and terminates the fleeting pulsation. The seething unrest, the heat, the clashing, kneading and rushing tur- bulence of the gigantic masses of suns and worlds in the midst of evolution must be hushed for a few moments into almost ab- solute quiescense and repose that life might appear and vanish, Thus life is a mere episode in the process of evolution of nature. RADIANT ENERGY. 275 XXXIX. EVOLUTION NOW IN ACTIVITY. "That which is one the wise call many ways. They call it Indra, Mitra, Varuna, Agni, the winged heavenly Garutmat." Rig Veda I, 164, 46. Stellar evolution has by no means ceased, it is in an active state now, and can be watched by means of the telespectroscope in all directions in space. Gemmation of one sun into two, allows tides to set in and furnish suns and worlds with moons. At the instant of separation of two worlds, tides must act and build both into suns. Gravity is inherent in all matter, but cannot build a universe unless it exerts its power by the leverage of tides and these cannot build without friction. Since friction is also inherent, gravity and tidal friction formed and fashioned all that portion of the sidereal edifice within range of the best telespectro-cam- eras, for these write the history of cosmic evolution hour by hour. Cosmical life and death seem to be equal. Suns ending evolution, so far as can be learned at present, are comparable in number to those entering their long career. The quantity of matter now stored in dead worlds is greater than that in the hot and living. The waste products, as far as science in its present condition is able to see, are heat and a minute trace of energy called light. Both are episodes and momentary while gravity is as eternal as matter. Heat, light and life are ephemeral, while matter and gravity are constant. All else in the universe at present known to men is variable. Gravity is the builder and has wrought in the 2 7 6 RADIANT ENERGY. past and is now acting through friction. Centrifugal tendency is a reaction merely against gravity. Gemmation prepares the way for its instant successors, gravity and its opposing entity. These two, and time, formed all worlds. Thus activity is derived from gravity. Matter and gravity existed before the universe assumed its present structural form, while astronomy and cosmical physics both teach that they will exist if it ends. If the fashioned struc- ture does not end, that is, revert to chaos, then evolution is eternal. Tt has, however, been decided by psychologists, that the word eternal is powerless to make impress on the human mind, so vagaries about duration must give way to what is known. MOTIONS OF THE STARS. The words "fixed stars" have now disappeared from the lit- erature of modern astrophysics. It is known that every star is in rapid motion. They move in every possible direction and the fact stands out that they move at random like bees in a swarm. It is almost impossible that any should move on straight lines. A right line is almost unknown in nature. The distances between suns are so enormous, that gravity is weak from sun to sun, so the curvature of solar orbits is slight. If the stellar structure is finite, it has a center of mass, and all suns and worlds whether alive or dead, must obey its attraction in a measure; yet a hun- dred suns in the vicinity of our sun might temporarily attract it more, than the immensely distant gravity center of all the suns. Since whether the universe is finite or infinite is unknowable, the center of universal attraction may be ignored, and attention paid to adjacent suns. Since they all move, the effect on every other is variable, so every sun in existence moves with varying velocity on a curve which is perpetually changing its curvature and direc- tion. RADIANT ENERGY. 277 Cut 114 represents a finite portion cut out of an infinite sys- tem of stars, with motions in every direction. Cut 114. Any number of Suns cut out of any space. They move in every direction. Cut 115 represents the observed and measured movements of the stars in the Great Dipper in the constellation Ursse Major, where five suns are seen moving in the same direction, all presumably condensed from the same nebula, while one af the pointers and one in the handle are in motion in other directions. These motions were measured by micrometer, but the spectro- Cut 115. Drift of Stars in the Great Dipper. scope shows that the five suns are in rapid motion away from the earth, while the pointer (A) is approaching and the star (E) receding with a speed different from that of the five common suns. All but eight of the stars of that well-known group, the Pleiades (cut 116), move in one direction, so all these glittering suns are supposed to have been condensed from one mass of gas. It is also known that our sun is moving with great velocity through lonesome space, dragging its worlds along with perfect 278 RADIANT ENERGY. order. Thus binary, ternary and multiple suns, as well as single stars like ours, and also groups, all have their own motions ; bin- aries, of course, and related groups having the same direction, in relation to each other, but every conceivable direction in relation Cut 116. Drift of Pleiades. to space and all the other stars. So there are no fixed or motion- less suns in space. Indeed, there could not be bodies at rest in free space dominated by the ruler of all Gravity. RADIANT ENERGY. 279 WIDE DIFFUSION OF MATTER. "Nature, beginning of ages, is parent of all." Diodorus 1-27. Apu- leitis, Metamorphoses. The writer has seen incandescent hydrogen glowing in the stars Vega and Sirius. Sirius sets when Vega rises, therefore they are in opposite directions from the earth. The distance between these two giant suns is 256 trillion miles, and they are in our im- mediate neighborhood, for other stars known to contain hydrogen are as much as one hundred times farther apart. The mighty question at once arises, how came hydrogen so widely distributed in interminable space ? It is omnipresent, and seems to enter the most archaic nebulae and thence condense into suns. But it is too dense to fill all that portion of space now known to be occu- pied by suns and cool worlds. Iron is conspicuous and also mag- nesium, together with helium, in the most primitive type of suns. When suns become older and more complex other modes are seen in the spectroscope. The only possible explanation of the fact that iron and hydrogen are seen glowing in suns in every di- rection, whose distance apart are many quadrillion miles, is that all matter now stored in suns and worlds was once separated into an exceedingly rare gas, or rather ultra gaseous form. For any gas known to chemists here, under terrestrial conditions, is many 2 8o RADIANT ENERGY. hundred million times too dense to be compared with the probable diffusion of primordial matter. Helium and hydrogen particles would be miles apart if all matter now existing in suns appearing on late graphic plates should be uni- formly distributed. And these are the rarest modes known. But the discovery of J. J. Thomson of corpuscles that have only one-thousandth of the mass of the hydrogen particle throws much light on the primeval chaotic mass, whence all suns and worlds were developed by processes of evolu- tion, now observed in activity in every direction in space. These corpuscles have awakened the interest of every physicist in the world, and they are either electricity itself or its immediate car- riers. A great fact seems to be prefigured the universe is based in electricity, for electricity, no doubt, is a mode of matter. At all events, speculate as one will, it is certain that if all matter now condensed into suns visible in the most powerful tele- camera were expanded into the same space now occupied by them, then space would not be filled, for even these corpuscles would be separated by distances very large compared to their diameters. Let all that part of space at present occupied by suns and worlds in every possible phase of evolution be occupied by mat- ter dissipated into an excessively rare condition, so rare that the Thomsonian corpuscles were inches or even feet apart then the development of the original mass into a universe such as now ex- ists was sure to follow from known physical laws. EVOLUTION OF SUNS. In cut 117, let the circle cut out space in diameter the distance traversed by light, moving with a speed of 186,000 miles per sec- ond during 30,000 years. This is not extravagant, for Sir Robert Ball, Astronomer Royal, estimates that the faintest stars of the sev- enteenth magnitude are so distant that 18,000 years are required RADIANT ENERGY. 281 for light to reach the earth, making the diameter of the cosmic structure visible to man 36,000 light years. To be within bounds, 30,000 years is the period selected for computation in this note. The circle is drawn merely to attract the eye, and has no other use. Kelvin has shown that the number of particles of any gas in one cubic inch cannot exceed six sextillion. The size of Thom- son's corpuscles is unknown, their mass only being determined, which is the one-thousandth that of the hydrogen particle. Doubt- less, however, their diameter is in some equivalent ratio, so the Cut 117. Cosmical Sphere of Suns, 30,000 light years in diameter. number above becomes one thousand times greater, or six septil- lion. In the appalling space selected, each corpuscle had plenty of room. The temperature was absolute zero 273 degrees C, and solid hydrogen and air would be warm in comparison. Absolute rest at first obtained, when the sole ruler of mat- ter gravity asserted sway, and motion began. If two corpus- cles united, that was the beginning of a nebula, of which many thousands are now seen in all parts of the sidereal structure in every conceivable shape, faint wisps and filmy forms of original gas born of condensation from primordial corpuscular matter. After inconceivable eons passed away, the appearance of things within the circle, so far as science can at present find, was 282 RADIANT ENERGY. like that in cut 118, where nebulae have formed in all parts of the sphere, starting from minute corpuscular nuclei. It is the destiny of every nebula to condense into suns, for the process can now be seen and photographed on every clear night. These countless nebulae are at present seen on the plates in every possible phase of evolution from the faintest and most diffused mass of rare gas Cut 118. Nebulae and Suns in evolution. up to the final or solar stage. In cut 118, amoeba form nebulae are shown; and also those in the shape of spirals, for Keeler's graphs revealed many to have the spiral form. Probably these were in rotation. All nebulae so far subjected to spectrum analysis show hy- drogen, others present helium, and many have lines emanating from a mode of matter not yet detected on the earth, provisionally named nebulium. D' 7 311 If \ III I Cut 119. Spectrum of a bright Nebula. I y ines 3, 4 and 5 are due to hydrogen and C is from helium. Lines 1, 2 and 7 are from an unknown mode, but called nebulium; 5 and 7 are faint and invisible in dim nebulae. Cut 119 is the spectrum of nebulae, only the brightest being able, in a powerful spectrograph, to show all of the seven lines. RADIANT ENERGY. 283 The line 6 is due to helium, which was unknown for a long time, always being seen in the sun as well as in nebulae. It was dis- covered by Ramsay on the earth in 1895, and isolated, when its line was found to coincide with the line in both sun and nebulae. Thus helium and hydrogen hover round about the beginning of evolution of the universe. Astronomy and astrophysics, in their present state, are un- able to see any other possible method of sidereal evolution than that here given. For, if all existing suns were evolved in the vicin- ity of the center of the circle, the problem comes up how did they become dispersed to such incredible and inconceivable dis- tances in which they are now seen ? Separation, due to Darwin's tides, seems to be impossible, for gravity becomes very weak at these enormous distances. In fact, the standing mystery of all astronomy is space. Why should suns now be separated by such unfathomable space ? Why should our nearest neighbor be 25 trillion miles away ? For it can be shown that if Alpha Centauri were only one trillion miles dis- tant our planetary system would not be perturbed by any measur- able quantity. Evolution extends from corpuscle to dead suns and frigid worlds. In the turbulence and turmoil heat was the first mode of radiance to appear, then light ; moisture came, and then life. But life is of exceedingly short duration. The evanescent, fleeting, unstable and feeble thing or entity life was the last to appear in the midst of the stupendous cosmic war of matter and energy, and will be the first to vanish. A few degrees change in temperature either way will end it all. Short as may be the dura- tion of organic life, that of its chief product mind is shorter still. For life existed ages on the earth before its last refine- ment, coherent thought, was evolved. Thus mind has the least duration of any entity whatever, for soon mentality will vanish, unconsciousness set in and oblivion succeed. 284. RADIANT ENERGY. It can be shown that if the sidereal structure is in rotation about an axis, the centrifugal tendency is unable to project out- lying suns to their present distance, so the conclusion is inevitable that all space now occupied by suns must have been filled with ma- terial whence they were made by gravity and tides. If so, then the tenuity of the mass was so great as to reach the ultimate or final corpuscular state. If, as seems probable in the present state of ignorance, cor- puscles are electricity, then electricity is the first and last refine- ment of matter, for the indications of astrophysics are that the sidereal structure must be resolved back to the corpuscular state again to recondense into another. This mutation is necessary to regain heat, which at present is being lost at a frightful rate. And modern science here has arrived at the same conclusion reached by our primeval Aryan ancestors at the base of the Hindu Kuh, in Northern India, many thousand years ago. For that recondite Hindu philosophical poem, the "Bhagavad Gita," says: "Matter is invisible in its primordial state, visible in its inter- mediate, and invisible in its final state." The latest science has nothing better to offer. Helium and hydrogen are the perpetual enigma. Why should the first matter to send out light be these? And how is it that iron appears so early upon the cosmic scene of upheaval, unrest and activity, or why should matter assume the eighty phases now known? Or what is matter? Perhaps these old questions never will be solved by man, yet the astound- ing discoveries of the last two years appear to indicate that they may not be beyond human powers. Cut 1 20 is that of the great spiral nebula in Canes Venatici. Several suns are shown that have been condensed from the vast mass of gas. To the right, a large body of gas is separating by the gemmation process, while the whole presents the outlines of a gi- gantic spiral. Thus the history of cosmical evolution has been given as far as science can see at present. Whether the entire RADIANT ENERGY. 285 Cut 120. Spiral Nebula. Canes Venatici. congeries of suns and worlds revert back to the corpuscular state at the same time, or whether, while some are dissolving to chaos, others far away are just emerging from it, are questions at pres- ent insoluble. The new sun in Perseus last year was seen to re- solve into a chaotic nebula. Mystery deepens, while men pale and faint in presence of these mighty problems. 2S6 RADIANT ENERGY. XLL PRIMORDIAL ELECTRICAL INDUCTION. "Thou art the arts and sciences, thou moral and political wisdom. The worlds have been preserved and reanimated by thee." Indra's Praise of Lakshima. From Vishnu Purana I, Ch. ix. Induction is a deep-seated fact in nature. In this paper elec- trical induction will be employed in striving to account for the archaic mystery of rotation. Very many theories have been advanced to account for the rotation of primitive nebulae, as well as spherical gaseous suns, and liquid, round about axes. How did rotary motion begin, and what mode of energy caused these vast masses to turn? In cut 118, Paper XL, the primal gaseous sphere is seen broken into great numbers of nebulae, and some are rep- resented as having passed their successive steps of evolution up to complete suns. But all worlds in our solar system, as well as the central sun, are in rapid rotation on axes. And from phe- nomena of variable stars it is inferred that all suns, planets and satellites are turning. The writer believes that this universal motion of rotation was caused by electrical induction. The phenomena of inductance ought to be understood by all, for nearly all electrical machines, now rapidly coming to the front as the workers of the world, are based on the fact that electricity acts at a distance and induces other mechanism to do work. RADIANT ENERGY. 287 This is cleared in cut 121, where A. B and C are spheres those so often used by the writer before students being wooden croquet balls covered with a coating of lead or tinfoil. The balls were all suspended by a silk, or non-conducting, thread to the ceil- ing of the laboratory. The ball A is to be charged by the in- duction of C. The sphere C is to be provided with a charge of electricity from an electrophorus, Helmholtz, Atkinson, or any static machine, in another part of the room, and carried to its position of suspension. Suppose the coating is charged positively as shown. It instantly, by induction, separates the natural elec- tricity, with which all known matter is endowed in the sphere A, CUT 121 Charging the sphere, a, with electricity by induction exerted by the electricity in the sohere, b. the negative moving to the side nearest C, by reason of C's attrac- tion, while the positive is repelled to the opposite side, as may be seen by the signs plus and minus. For unlike attracts and like repels. Separation is one of the chief mysteries of nature, and always precedes attraction. The ball C must not be allowed to touch A under any circumstances, for then A would be charged by conduction not induction. At this point, gradually bring B to the position shown. Lightning will dash across the space between with a snapping sound. The positive on A flies to B, and soon as this occurs the sphere B must be removed, and C also, leaving A alone in the air. Now, since man began to handle electricity nothing more wonderful than this has been seen by mortal eye, nor ought that seems to approach nearer the confines of nature than the strange property now possessed by the sphere A. 288 RADIANT ENERGY . LAW Electricity on its surface has power to attract and cause motion in every mode of matter. This activity is shown in cut 122, where a and d are suspended as before, while e is a hydrogen toy balloon attached to a peg below. By reason of the experiment, a was charged negatively; but by the same method it might have been endowed with positive, in either case it will attract any substance known. This is shown in the mass d, which has been tried with wood, stone, glass, metal, CUT 122 The charge sphere, a, .at- tracting and causing motion in any known mode of matter, d, and also in a hydrogen balloon, e. tallow, paraffine, oil, rubber, paper and other substances, and they all move toward a as shown by dotted outlines. Gases are also at- tracted as in the case of the hydrogen in e. If the shape of d is unsymmetrical with regard to its center of mass it will also rotate on an axis. If a is moved around d in a circle d will rotate at the same rate, following every motion of a. Let a be removed to a distant part of the room. Then d will still continue to turn until brought to a rest by friction of air and torsion of the thread. LAW The mass d in a vacuum would rotate forever. And the hypothesis of archaic induction is advanced here with the hope that obscure cosmological problems may be cleared. In cut 123, the principles of inductance, separation and attraction wrought by static electricity are transferred from the physical laboratory to the primitive and formative cosmical masses after they had advanced from the original corpuscular state to widely separated and slightly condensed nebulae. Let the nebula RADIANT ENERGY. 289 a be negatively charged as in cut 121. Lightning is seen escaping in a positive charge to the nebula at the left. Then let nebula a, carrying its wonderful power of attraction, in addition to its inherent gravity, wander among its neighbors at random. Let it pass b in the lower portion of the sphere. It will separate the electricity in b and the total negative quantity in a will attract the positive and repel the negative in b, forming a mechanical couple, and cause b to rotate in the direction of the arrow. [ Cut 123. The Negatively charged Nebula A, is supposedjo cause rotation in B by Electrical Attraction. For there is no more reason to doubt that electricity was present in vast quantities in the primitive nebulae than to doubt that it is in intense activity in terrestrial clouds of vapor. In early stages of evolution before suns appeared the most appalling lightnings flashed from nebulae to nebulae, whose dimensions in many cases then, as are plainly seen now, were hundreds yea, thousands of times larger than that vast nebula whence our own sun was formed. What mighty import hovers round the word evolution. For giant modes of energy wrought and struggled in war. Matter was shaken, oscillated, kneaded, boiled and tumbled in the throes of chaos. Phantom forms of nebulae were clutched in awful 290 RADIANT ENERGY. churning, in seething whirlpools, and throbbed with energy. Ab- solute zero and darkness reigned, useless indeed; cold light can be in the most frigid space. And silence reigned save from lightning, in the twisting gaseous masses, for friction had scarcely set in. The hosts of nebulae were not yet in the relentless grasp of the Darwinian tides. But when pent up electricity burst all bounds with the concussion as of a hundred worlds of broken glass, primordial thunders rolled without ear to hear. As soon, therefore, as electricity was separated by induction, one por- tion escaped by flashing to another ; then that nebula had potency and power to move through space and set up rotation in all other nebulae adjacent to its erratic pathway. And some other oppositely induced mass would also cause it to make rotation. It is known from mechanics that whatever movement of rota- tion was impressed upon a nebula by another passing it, must be retained forever if space is vacuous. Here is the great law of conservation of areas: LAW. When a system of particles, in rotation, changes form or size, the sum of all the areas described by each, in any unit of time, is constant. This is one corner stone of that edifice, the visible universe. A particle in making one circuit around the center describes a circle which has its own definite area. Now let the diameter of the rotating mass shrink to one-half, and if it still remains a sphere, the area of the circle cut out by the particle in its new position will be only one-fourth. Then it must rotate four times faster to cut out four circles which together will have the same area as the large one. The motion is called areolar velocity. Therefore, the earth now has the same quantity of rotary motion that was imparted it when a rare nebula by ihe gravity and inductance of some other nebula that passed it in primordial times, less than consumed by tides. RADIANT ENERGY. 291 QUANTITY OF MATTER. In cut 124 let the sphere be such that light, having a known speed of 186,000 miles per second, requires 30,000 years to trav- erse its diameter. Imagine the sphere to contain 500,- 000,000 suns, each containing the same quantity of matter now stored in our sun, and let them be uniformly distributed as shown. Consider a to be a stone or sun falling from infinite space^ that is, it has fallen forever. Of course, the two words infinite and forever make no impress of their true meaning on such weak minds as those now possessed by man. For man is ignorant con- cerning duration and space. It can be shown by rigid mathe- Cut 124. Sphere of Suns and Dark Bodies, whose diameter is such that light moving 186,000 miles per second, requires 30,000 years to traverse. matics, and has been by Newcomb and others, that the final ve- locity on arriving at the center of mass of the sphere of suns would be twenty-five miles per second. But the sun 1,830 Groom- bridge is now seen to be flying with the terrific velocity of 200 miles per second, at least. For Newcomb does not give its paral- lax in his late work, "The Stars," showing it to be so far away that astronomers are unable to measure its distance. Its velocity is beyond doubt more than 200 miles per second. This leads to the most remarkable conclusion regarding the quantity of matter within the 30,000 light year circle or sphere. ACTIVITY AND VELOCITY. From dynamical laws it is known that it requires four times the force to double the speed of a falling body. Thus doubling the motion to fifty miles per second requires four times the num- 292 RADIANT ENERGY. ber of suns, or two billion. Doubling again the speed is 100 miles, with eight billion suns. With double this, or the terminal velocity, of 200 miles per second, the number of suns required is thirty-two billion, each one being as massive as our sun. The graphic plates with long exposure, even to the faintest magnitudes able to make impressions, show less than 125,000,000 and more than 100,000,000 suns. Admitting that each contains as much matter as the sun, then only one in 320 emits light strong enough to impress the most sensitive plates. But our sun contains suffi- cient quantity of the matter to make 333,000 worlds of the size and density of the earth. Then 333,000 multiplied by thirty-two billions equals the mass of eleven quadrillion bodies like the earth attracting the flying star. The visible sidereal structure is of in- conceivable antiquity and is far more massive than thought pos- sible. Blackened death has encountered most all the suns ; only one in 320 is now emitting life-giving heat and light, or being pres- ent to throw feeble and fitful gleams on their funereal paths. Another star is now known to be moving faster than 1830 Gr., making the visible and invisible universe still more massive. RADIANT ENERGY. 293 SUMMARY. The latest deductions of science are that evolution set its mighty clutch on all existing matter when it was in an excessively rare ultra-gaseous or corpuscular state, filling all space now oc- cupied by suns. Gravity was the only mode of energy, and the first to act. Nuclei formed and these attracted adjacent corpuscles form- ing countless nebulae. These still contracted and grew more dense. Electricity appeared and began the work of building a universe, of rotating suns by induction. Heat and light came later on the primordial cosmical scene of turmoil, save that momentarily ap- pearing at times of the outbursts of electricity. The heat and light evolved by contracting suns came far later, as well as from chemism. Gemmation wrought also in nebulse as well as in gas- eous and liquid suns, separating one into two. And the process of division continued in planets and their moons. Soon as gem- mation finished its work producing any two suns, then that mighty and chief builder, the tides, laid hold on the primeval masses and fashioned both into suns and worlds revolving in reg- ular orbits around their centers of mass. Through contraction, heat developed and light on small worlds after nearly all the heat had vanished, water came, and coarse life, then more re- fined, and lastly mind, along toward the close of evolution. It contemplates the stupendous scene a few seconds and disappears. Each mind gains one or two impressions of the objects on display and dies. Were it not for the custom of recording these fitful 2 94 . RADIANT ENERGY. thoughts and ideas, in print, in sculpture, on obelisk and walls, on bricks and cylinders, and now by that marvelous process making records on graphic plates ignorance would reign su- preme, for it is only by storing minute fragments of knowledge gained by each, that a fund can be accumulated. Coherent thought in modern times began in 1610, so it is but 300 momentary years since wisdom began to be stored. For the awful and withering poison of the dark ages subverted mind. The three centuries have produced the lens, the calculus, the grat- ing and the graphic plate, four engines with which men are now hourly wresting new and long delayed secrets from nature. Be- ginning evolution in corpuscular conditions, the universe of mat- ter passes all stages of youth, adolescence, maturity and death, the death consisting of loss of heat. Then if the titanic founda- tions are torn up and billions of dead suns and frigid worlds are hurled together with the most appalling speed so that heat enough due to collision and friction will be developed, to dissipate all back to corpuscles again, refilling the same space, the total mutation will have constituted one sidereal universe and made all things ready for another. Thus one phase of matter will have been passed the whole constituting one wave as shown in cut 125. Cut 125. One Wave. THE END. ADDENDA. The Lowe Observatory.* The location of this observatory is unique in many respects. It stands on a peak whose apex was cut off abruptly to secure a flat surface for the building. This central summit is in a vast amphitheatre, formed of colossal peaks round about, some on a level with the observatory and others 1200 feet above. On either side are yawning canyons. Rubio on the east, 670 feet deep, descends precipitously from the walls of the observatory; while Los Flores' Gorge makes rapid descent to a depth of 1250 feet on the west. A chain of old Sierra Madre's range is bent and coiled in mighty links enclosing both canyons, the central, or Echo Mountain, and observatory peak, and extends from the southeast round through the east and north, through northwest, and rapidly declines to the west, where the range dwindles into the Verdugo hills overlooking that paradise of oranges, apri- cots and grapes, the famous La Canada Valley. Still beyond and nearer the sea, eight rows of hills, ranging from north to south, are visible. These are the Tejunga hills and Simi and Santa Monica ranges of low mountains. Speech is impotent to portray the glories of the sunsets from the vernal equinox to the summer solstice and return to the equinox of autumn. The angles made by these ranges with the ecliptic, are such that the declining sun pours its radiant floods between, lighting up the *From the Bret Harte Memorial Number of the OVKRLAND MONTHLY, Sept., 1902. 298 LOWE OBSERVATORY. gloomy and solitary canyons with supernal colors. For dust 1 from waste places on the hills, and from Mojave's desert areas, comes in contact with watery molecules thrust over by the break- ers of the Pacific in their dashings against Simi's granite bul- warks, and these absorb and quench some of the waves of light, allowing others to illuminate summits, valleys, canyons and domes with hues and tints, all blending into one stupendous panorama of surpassing loveliness and beauty. So remarkable is this scene that iron railings are placed on the canyon's edge, for travelers from all parts of the earth, who come to behold the sun as it sinks into the sea. It is Sunset Point, Los Flores Canyon. But it is to the mighty and serrated contour of cliffs and peaks that scientific interest is attached. So transparent is the air that minute stars are seen at the absolute instant of rising. Thus the writer never saw a star at the moment of its advent above the horizon, until coming to this enchanted place. Not sorcerer of Egypt or Eleusis ever conjured up a more magnifi- cent spectacle, or weird influence, nor impression more fasci- nating to mind and sense, than the marvelous display of rising celestial bodies. The great nebula in Orion issues out of a smooth wind and sand-worn rock, and so clear is the air that five stars in the trapezium have been seen standing on stone, while the light of the great nebula suffers but little diminution. Since the telescope reverses all objects, rising stars seem to be going downward toward the earth, and language cannot describe the wonders of the rising falling Pleiades, for this glittering host of 1300 stars, as seen in the L,ow r e telescope, seem to be pouring into old Rubio's cavernous depth. And the unutterable glories of the Galaxy how see them in a lifetime or how recount their splendors for illimitable hosts of stars pour in floods into the chasm and this Niagara of stellar diamonds, rubies and sapphires, flows with stately motion into the insatiable recesses below. The edge of Saturn's ring cuts its way up and out of a rocky cliff, LOWE OBSERVATORY. 299 and Jupiter at times sends up a tiny moon before it appears; but last night it escaped from a tangle of manzanita bushes far on the mountain's height. The star Castor is seen double be- tween the leaves and branches of a shrub, while the nebula of Andromeda is always enmeshed in a wilderness of low-growing chaparral. Altogether this clear-cut mountain horizon is so beautiful that description fails and words lose their power. THE SIDEREAL STRUCTURE WITHOUT THE TELE- SCOPE. Many more stars can be seen here without optical aid than from low plains. The observatory is above more than half of the dust layer that encloses the entire earth as an envelope. It is no trouble to see the sixth magnitude stars. The stars burn and blaze with a brilliancy unknown to observers below. Sagitarius and Scorpio hang up their sidereal sheets like a drapery of cloth of pearl over the waves of the Pacific. The Milky Way is whiter than as seen from observatories in Illinois and the East, and the sky blacker. The colors of the stars are on display with greatly increased splendor, and contrast is more pronounced than elsewhere. But all glories pale and faint be- fore that awful and sublime object as seen in the Lowe telescope. THE STELLAR FLOOR. The majestic pavement of the universe is surely visible from this observatory. It is the background or foundation of the sidereal structure. It is either made up of countless millions of inconceivably distant stars, or a solid external envelope of nebu- lous matter. It is beyond the Milky Way, and wider. It is not visible in all parts of the sky, but areas far removed from the Galaxy are filled with it. The general structure of nature is surrounded or clothed with a fabric of pearl ; but the delicate texture is rent and torn in thousands of places. The appalling joo LOWE OBSERVATORY. blackness of space appears in these ragged openings. Cosmical rifts, cracks and seams are seen here in great numbers. Special observation has been made of Scorpio and Sagitarius. Over one hundred rents and jagged openings in the white stellar floor have been seen in these two constellations. Some are clear-cut and small, others large, diffuse, with torn and twisted edges, and these are not jet black within. A film seems to be stretched in front. It is doubtful if the white floor is entirely absent even at the Galactic poles. When taking charge of this observatory, the first thought was a mistake had been made concerning the winding sheet of the visible universe; so nothing was published for one year, to test the seeing in all kinds of weather and con- ditions of air. It was surmised that the white shimmer and sheen in the distant background of the cosmical sphere, was due to the well-known action of dust causing diffusion of light in the earth's atmosphere. Many tests were made on this point, with the result that the cosmic floor was seen in certain localities, on the same nights, when black space was seen between stars in adjacent and also in distant regions. So it is said that the pri- mordial substructure of the universe is on display here. It is doubtful if long time graphs will show this pavement as well as the eye, for the stars in the foreground will store their light in ex- cess in front of the distant wall. If the azoic rocks of stars or nebulae really exists below and beyond all, then the sidereal edifice is far more magnificent and larger than hitherto thought possible. That is, that portion of the structure visible in telescopes, or on plates, is merely cut out of an original universal nebula. STARLESS FIELDS. If the stellar pavement is impressive, what shall be said of those caverns in which no star is seen, nor any nebulous gleam of light. After looking for a long time at the multitude of stars, finer than any sand, or as fine as the granules of silver bromide LOWE OBSERVATORY. 3 oi on graphic plates, the telescope sweeps into view a space black as ink, the effect on the mind is always startling. It is difficult to account for these openings in the structure of stars, for there must be long, empty tubular spaces extending from the place of the earth, even to the floor of stars. At all events, they are black. Here long exposure of sensitive plates might store light enough to make visible impress, and long-time graphs should be made of central portions of the blackest starless areas. Here is a list of several spaces in the starry pavement: PHOSPHORESCING AREAS OF THE COSMICAL FLOOR. Right ascensions. Declinations. H. M. Degrees. Minutes. 3 20 2 50 2 30 23 55 22 OO 21 45 21 00 Next to the last in the table is notable, for the floor and a star- less area are seen in the same field of view, both distinct. The edges of the pavement are smooth, like the rim of a well cut in stone, while the second in the catalogue has rough and distorted boundaries of stars round about the cavern. STARLESS FIELDS. APPROXIMATE CENTERS. 16 50 S 22 20 l8 10 S 20 17 25 S 26 35 18 10 S 18 25 18 Si8 50 18 13 Si8 i 18 384 5 42 S 8 20 38 30 9 20 South 1 8 50 56 00 38 40 45 30 South 26 00 302 LOWE OBSERVATORY. These positions are for the centers of the dark areas. A very large black space is in Scorpio, above the bifurcation of the Milky Way. It is doubtful if any of these places are absolutely black ; they seem so to the eye through contrast probably. There is light in all that part of space cut out by the universe. How futile it is to attempt to make drawings or cuts of the shape of the cosmical edifice. Its plan is still unknown. It is well enough, perhaps, to make specifications of the Galaxy and adjacent stars, yet all these are tentative so far. The foundation lower than the Milky Way the original granite of stars or corpuscles must be studied and graphed for a century to give an idea of the plan of nature. And then, after all, the problem may appear to be beyond the reach of man. At all events, much attention should be given to this wondrous and original cosmical nebulosity. Nearly all the. larger nebulae visible here are complex those with clear-cut boundaries in small telescopes, show fila- ments and streamers in the Lowe instrument. The Andromeda nebula displays intricate convolutions, and looks like those shown in recent graphs' having the supposed appearance of a rudimen- tary solar system. The trifid nebula presents an infinity of detail not seen in a six-inch telescope, likewise the Omega nebula, while nearly the entire constellation of Orion is simply enshrouded in nebu- lous sheen, the great central nebula showing a wealth of out- lying wisps, streamers and spray. The dark opening is not dark, for faint light is always seen here. It seems dark by contrast only. There are two filaments extending across the opening at nearly right angles to its length. It is remarkable to have an ocean horizon on the south, for stars rise, cut out small arcs and set in the waves, all within a few minutes in the distant south, The giant sun Canopus thrusts its fiery darts through the mists of the sea, and then vanishes behind the walls of Catalina Island. In coming here from Illinois, Lat. 41 degrees, 13 minutes, to Lat. LOWE OBSERVATORY. 303 34 deg. 17 m., a zone of stars, 7 degrees wide, was lifted up, all new. It has been explored with interest. Not the least among its glories is the wondrous Omega Centaur i cluster, where 8,000 fine stars are piled in heaps in a small area. It is impossible for one to form any conception of the splendors of the Milky Way without seeing it in the great glass, and then it is still impossible. The Galactic hosts are splashed and strewn in spray, in spirals, and jare tumbled in confusion on a carpet of jet black velvet; or cosmical hail of pearls and diamonds on black- ened wastes of space, or piled in heaps, raked into windrows and rolled into banks and bulwarks, all flashing and blazing with su- pernal colors. These, together with clusters and nebulae, con- spire to form a scene surpassing all that mortal eye can ever hope to behold. And beyond all is the primordial base, the cosmic floor. A typical area of the stellar pavement is between the trifled nebula in Sagitarius and nebula No. 6523, Dreyer's N. G. C. The masonry is complete, with no more room for starry sand. Accompanying this article is a graph of a portion of the Milky Way in the southern constellation, the Centaur, invisible from these latitudes. The ring around the star Beta Centauri is a diffraction ring due to the action of the lenses on light and not actually around the star. The minute specks on the graph are all suns like our own, and the spectroscope shows that they are all composed of the same modes of matter whence our sun and earth are made. One of the chief discoveries of all ages was the fact that all that part of the universe within range of the most powerful telespectrographs is made of the same matter the side- ral structure is a unit. The black cavernous opening shown to the right and above the star is most awe-inspiring, and, like these seen in great numbers in the fine telescope in this observatory. The object glass is 16 inches in diameter, and the focal length is 22 feet. It was made by Alvan Clark, Sr., with his own ven- L W II OBSERVATORY. One of the richest regions in the Milky Way in the Constellation Sagitarius, from photograph by Barnard at the Lick Observatory, June 19, 1892. LOWE OBSERVATORY. 3 o 5 erable hands. It is simply perfect. The writer had the good fortune to be with Mr. Clark, half a day, in his famous work- shop in Cambridgeport, Mass., when he was making the flint lens, and every particular of lens making was explained and shown by this remarkable man. Little did the writer think that he would ever be putting it to active use on the summit of a mountain in that fairy-land California. This occurred in 1879. MODERN ASTRONOMY AND ASTROPHYSICS. The new astronomy is quite unlike the old. The introduction of the spectroscope changed all, and then came the sensitive plate and made another change. The early astronomy contented itself with rinding every mathematical law of the solar system and of the external sidereal structure; of finding the mass, volume and density of the sun, planets and satellites, and of a few stars, and continued the work of the practical astronomers, in the compu- tation of the moon's place, for time, and the making of Ephem- eeides for use in observatories and by sailors, and a vast amount of valuable and necessary work. But now comes the astrophys- icist and tells what the stars are made of; writes their history through the eons of the past, and forecasts their future. The capital discovery stellar evolution was made by the science of astrophysics. All stars whatever are incandescent suns. They grow from primordial nebulae through infancy, youth, middle life to old age and death. They are now seen in every direction in space, in every possible phase of evolution. Leaves in a forest do not pass so many and varied changes as do the glowing suns. The spectroscope detects every condition, reveals relative ages of suns, and then, that marvelous thing, the graphic plate, catches the fleeting changes, and records them for use for future astrono- mers. Nature cannot lift a hand anywhere in space within the reach of modern instruments without being instantly graphed. Her most secret laboratories and labyrinths are being explored jo6 LOWE OBSERVATORY. hourly. A plate is exposed every hour of the year somewhere on earth. For if the stars are setting at some observatory they are rising or passing the meridian at others. That imperturbable eye the bromide plate is always gazing at the stars or sun. Thus, for 1901, graphs were secured of the sun on 361 days. Astonishing discoveries are now being made, and the great bundle of magazines, monographs, reports of observatories, tech- nical papers, treatises and circulars by the dozen, received almost daily present a most impressive display of the present intense activity of the human mind. Since history began there has not been such incessant labor wrought. And no labor ever performed by the human frame is more arduous and exacting than that hourly engaged in by a working astrophysicist. A trained astron- omer is a machine of precision, with every phase of bodily life? every faculty of mind, everything in his being, an abject slave to indomitable will. And that will is immovably set and bent on finding the secrets of the vast cosmical building round about. RESULTS. The universe is now known to be a growth. Evolution is seen to set in with the faintest possible rare masses of gaseous neb- ulae. They condense into smaller and brighter objects. Con- densation continues for countless ages, and each becomes a sun. Heat ever escapes, each sun passes its zenith of glory and dies. If a dead sun happens to be drawn into an orbit around a living one, the body so drawn in becomes a planet, and may become inhabited, and undoubtedly will if water appears. Finally both planet and sun expire, and the lifeless planet will still make cir- cuit around its frigid sun and count off useless years unless there is a resisting medium in space. If so, the revolving world will wind down a spiral and ricochet on the surface of the central sun, the impacts liberating heat again. The only hope of reanimation of dead suns and ruined worlds LOWE OBSERVATORY. 307 is by wholesale collisions where these bodies by the billion rush to a common center and generate heat enough to- dissipate all back to the original corpuscular state again. Countless suns are now seen to be dying from loss of heat, and from motion seen in some notable stars, it is coming to be realized that the quantity of mat- ter now stored in dead worlds is greatly in excess of that in the living. The whole sidereal edifice has been graphed on more than 25,000 plates, in pursuance of the act of the Congress of Astronomers in Paris in 1887. Many of the stellar images on these have been counted under microscopes. If all have the same average, the total number of stars appearing will fall between 100,000,000 and 125,000,000. But assign to each of these any mass within bounds of reason, then by the laws of gravity and motion, it can be shown that they contain only a minute fraction of the entire quantity of existing matter. Hence dark worlds are immensely more numerous than those that are active, giving out heat and light. So that those now shining are mere funeral tapers, lighting up the cheerless and melancholy pathways of an- cient suns and forsaken worlds. That part of nature within reach of the best telescopes is of inconceivable antiquity and mag- nitude. The first and amazing fact encountered by astronomers is that of the interminable space round about. For the nearest neighboring sun to ours is 25 million million miles away, and oth- ers are a hundred, yea, a thousand times more distant. In the evolution of suns, so far as science can now see, heat was the first to appear in condensing matter, unless, indeed, electricity, or "cold" light preceded it. Primordial absolute zero, besides which frozen hydrogen and solid blocks of air appear warm, pre- ceded activity. At all events, light succeeds heat. Moisture appeared late in evolution. Then tardy life came upon cool worlds, and that evanescent, transitory and ephemeral, ultimate and final refinement of matter mind was the last to appear in the midst of the tremendous cosmic scene. It cannot exist long, 308 LOWE OBSERVATORY. for such worlds as the earth are habitable for an hour or a day only, compared with the duration ofa structural universe of mat- ter. So mind and life will be the first to vanish. Absolute zero of temperature is the normal condition of matter and space. For when primordial matter was so attenuated that a volume of it of the size of the earth only contained enough to weigh 127 pounds, it did not retain heat. So heat, light, life and mind appear to be mere episodes in cosmic fluctuations and surging of matter. As- trophysics has shown the earth's place in nature. The dust, of which easily 1,000,000 particles are lying on the page of the Overland Monthly, are each as large in proportion to the thick- ness and area of the magazine, or of the cubical space of the room in which the reader may be, as is the earth to that portion of space included within the envelope of stars at the extreme limit of vision in the 4O-inch telescope. These stars are of the sev- enteenth magnitude, and from photometric observations it is al- most certain that they are at least so far distant that light trav- eling with the known speed of 186,000 miles per second, requires 15,000 years to come hither. This makes the sphere of suns vis- ible in the Lick and Yerkes glasses, 30,000 light years in diame- ter. The particles of dust, 1,000,000 to the page, are too large. So now, astrophysics has demonstrated its extreme value, for man for the first time on earth knows the earth's place and his own. THE INCLINED RAILWAY. Neither Suphis, the monarch builder of Egypt, nor Rameses II., did a greater work than the inclined railway up Echo Moun- tain. Engineers and railroad contractors from all parts of the world pronounce it to be a model of high-class engineering. Its length is 3,000 feet and vertical ascent of 1,325 feet, with grades of 45, 48, 55 and 62 per cent. Two white chariots balance on one endless steel wire cable, the car Rubio being down, and Echo invisible at the top, to the left of Hotel Chalet in the cut. There LOWE OBSERVATORY. 309 The Inclined Railway, Echo Mountain, California. Length, 3,1100 feet. Vertical Ascent 1,325 feet from bottom of Rubio Canyon, to the top of Kcho Mountain. Time of ascent of cars, eight minutes. are three rails with two cars which pass automatically half way up at the switch, which is shown. The great motors are at the top, and are actuated by electricity, brought from the Santa Ana river 90 miles away. The current comes to Pasadena on three wires at a pressure of 33,000 volts, with 50 cycles. Here it is stepped to 2,200 volts and sent to the power house on Echo Moun- tain, where its potential is again lowered to the usual railway pressure, and made direct by a General Electric Company 20 am- 3 io LOWE OBSERVATORY. pere induction motor. In case this circuit should fail, there are dynamos at the foot of the incline in the building to the left, turned by two Pelton wheels, run by water from a reservoir near the observatory, 1,500 feet above. The pressure is terrific, and the struggle of the water to escape its narrow prison, the half- inch nozzle, the hissing and trembling and throbbing of the pent- up force, are impressive. The escaping water has more the ap- pearance of a solid rod of metal than a thin liquid, and would instantly take the life of a man if it struck squarely over the lungs. The white chariots, Echo and Rubio, making ascent in eight minutes, lift the startled tourist from the gloom lowering in the canyon below to a stupendous transformation scene above. If, as often happens in the rainy season, clouds extend from the depths of the canyon to half the height of the incline then lan- guage spoken or written or brush or pencil of artist are im- potent to portray the marvelous change that awaits the traveler. Unrivaled splendors burst upon the startled eyes ; and not the sumptuous transformation of scene-painters, nor wand of ma- gician, nor witchery of optical illusion, nor spell of enchantress, can equal it. Under the great tree to the right, at the foot of the incline, is the mouth of Rubio Canyon, hewn in primeval porphyritic rock. It is a rift or gorge in the mountains formed on that auspicious day when good Dame Nature lifted up old Sierra Madre's range, through the bottom of an ancient sea. It extends to a depth of 1,000 feet under the hotel, and continues in sinuous course to the observatory, where its depth is 670 feet. This canyon is wild, and within its jaws nature at first frightens, and threatens to hurl chaotic rocks upon the explorer, and then pleases, dispels fear and woos with ferns, flowers and trailing vines with cool streams and miniature whirlpools, until one arrives by winding stairs at the foot of Rubio Falls, 100 feet in height. The peaks to the east of the observatory are rightly named Echo Mountains. LOWE OBSERVATORY. They repeat all that is spoken to them, and if one stands in the right place he hears seven echoes. The colossal walls met with a surprise last spring. The great singer, Calve, came and sang and poured forth her wealth of song. The startled rocks were taken all unawares, and at first, were abashed. For nameless centuries they had not heard sound save that of hoarse notes of raging elemental war. Their chagrin and discomfiture remained for a moment only, when they relaxed their stony throats, and answering, gave back all the marvelous tones. The great circular bridge far above the observatory on the road to Mount Lowe is also a marvel of engineering. The view from Lowe Observatory is one of beauty and magnificence. The land area visible is 900 square miles. In every direction the land is arranged in squares and parallelograms, planted to oranges, lem- ons, apricots, olives, prunes, peaches, figs, nectarines, almonds, grapes, and walnuts. Kaleidoscopic changes of color succeed in the flowers and leaves throughout the year. The green is per- petual. The entire valley is a scene of intense activity from Christmas to May, gathering, packing and shipping oranges and lemons. In summer the apricot harvest is a sight to behold, and in autumn it is difficult to secure workers to gather the tons of grapes. The writer dare not attempt to describe the climate. One must live here to form any conception of its loveliness. The extensive ocean front is being transformed into a continuous sum- mer resort for miles, as fast as money and men can build cottages, bath houses, wharves, walks and everything else, like Atlantic City, Long Branch, and all other Eastern beaches. Cloud effects on Mt. Lowe in the rainy period are a never ending source of wonder. Thus one may be reading near a window in bright sun- shine. Suddenly the printed page grows dim, a cloud has con- densed in space round the building and against the window pane. Sunsets have been attempted by artists, and also by able writers^ who handle words as one would sticks and stones, but both find 312 LOWE OBSHRVATORY. II u o (U tn N LOWE OBSERVATORY. their powers begin to fail and wane. When the entire land and sea are covered with clouds, say from 100 to 1000 feet below the observatory, the top layer is simply indescribable in its supernal glory. It is then the sun is supreme in its inconceivable majesty and splendor, for the earth is invisible. And again, it is no oc- casion for surprise that our own great ancestors the Aryans worshiped the solar globe. GREAT ELECTRIC STORM. A most appalling electric storm raged here during four hours on the night of June 10, 1902. No rain fell. It was a remarkable conflict of lightning and riven peaks. Terrific flashes of chain lightning burst forth from inky clouds at the rate of two per minute during the four eventful hours. The thunders of Gettysburg and Chicamauga roared and crashed round the frightened summits and bellowed to the lowest canyon's depths. The awful turbulence of Mount Pelee was repeated, perhaps as far as electricity could imitate that upheaval. Lightning was seen' to strike peaks many times. One bolt fell close to the observa- tory, and one struck the Chalet Hotel. The vast cloud masses came from the northeast. After bombarding the mountain for three hours, the entire mass moved southwest and became de- pressed perhaps a thousand feet. This had the effect of mak- ing the center of the storm appear to be on a level with the ob- servatory, with the astonishing experience of beholding the top and side of a terrible battle of electricity. The sinister monster the widening cloud spread over Pasadena and Los Angeles. The explosions of electricity were almost continuous with each streak of vertical lightning. It seemed that both cities were doomed to certain destruction. This display, awful in its grandeur, kept up for one hour, then moved away, and hurled its furious rage upon the sea and rushed towards that bulwark, the 3*4- LOWE OBSERVATORY. LOWE OBSERVATORY. mountain island of Catalina. No damage was sustained by either city, while a slight but welcome rain fell. NOVEMBER METEORS. The literature of the world recounts the glories of the shower of meteors as seen at Niagara Falls on November 13, 1833. But whatever splendors were beheld there, they could not be more magnificent than the impressive display on this silent and soli- tary peak from midnight to dawn on November 15, 1901. It was a fire of shot and shell, from one to five per minute a ce- lestial battle entirely without sound. This intense silence made the scene one of the utmost sublimity, and the effect on one's mind cannot be conveyed to another. Swords, scimiters and flashing spears were thrust against a hundred lightning-scarred and sand-sculptured summits. Vast bombs, aimed at peaks, burst into glittering fragments, only to be succeeded by others, some aimed, so it seemed, directly at the white dome of the ob- servatory. Others shot with terrific speed into the wilderness of electric lights in the slumbering city below, and still others hurled themselves into the sea, or sought to throw down the battlements of Santa Monica mountains in the distant west, or disrupt the walls of Catalina in the south. Of course, these ef- fects were due to perspective, not one being, doubtless, within fifty miles of the earth. The wondrous apparition was on dis- play until the advancing splendors of the sun came on and put out the light of all lesser glories. During this memorable shower, 661 meteors of all sizes were counted. The writer was alone in the majestic solitude, and therefore saw at the most only one-fourth of the entire fall. Referring again to the impres- sive silence, it is well to say that it makes powerful impress on the mind. At the midnight hour, the stillness is so profound, that by a slight excess of mental imagery, one might think he heard sound issuing forth from the axis of the earth in its turn- 3 i6 LOWE OBSERVATORY. t o LOWE OBSERVATORY. 317 ing. Nature sets up opposition everywhere and it is a study to see the rivalry between the humming birds and bees for honey on the mountain slopes, laden with their burdens of flowers. So, to geologists, biologists, entomologists, botanists, mineralogists, microscopists, metereologists, naturalists, lovers of nature in her most splendid forms and modes, students of the sea, growers of fruit, engineers, electricians, railroad builders, mountain climbers, explorers, spectroscopists, photographers, artists and astrono- mers, it is said, come to this wondrous place Echo Mountain. For: "To him who in the love of nature holds Communion with her visible forms, She speaks a various language." But she speaks not in more tongues than here; strange dia- lects of nature speech seem to come up from the canyons, and new words of wisdom from the mountain walls. Nature teaches in the midnight hour, and repeats her lesson until solar glories appear in the East. Runic writings, Egyptian glyphs and Cunei- form script are everywhere impressed on plants, in the canyon's abyss, on the [mountain sides, in the vale below, and amid the labyrinths of space between the stars above. And had' Bret Harte, the lover of nature in all her varying moods, whether lowly or magnificent California modes which he made his own ; had that poet of nature, who sang of her splendors amid "the pines by the sea," or "in the valley below," or beheld some nature-glory "across the distant unfathomable reach/' stood here at sunset point on the canyon's brink, to> see a day die ; had Bret Harte been here on this summit in fairyland when lightning flashed, or meteors shot across the midnight sky, or had he lis- tened to the voices of nature in the night, issuing forth from gaping canyons or granite walls, had he been here, he would have found words to convey impress of the amazing scenes to 3i8 LOWE OBSERVATORY. other and waiting minds. For did he not bring pre-histonc time to the present when he sang of a cone from one of the gigantic trees of Mariposa, a "Brown foundling of the Western wood, Babe of primeval wilderness. Long on my table hast thou stood As though ten centuries were not Imprisoned in thy shining case." And this rivaling Burns in the poem "Hearts Ease:" "By scattered rocks and turbid waters shifting, By furrowed glade and dell, To feverish men thy calm, sweet face uplifting, Thou stayest them to tell The delicate thought that cannot find expression. For ruder speech too fair, That, like petals, trembles in possession, And scatters in the air. The miner pauses in his rugged labor, And leaning on his spade, Laughingly calls unto his comrade-neighbor. To see thy charms displayed." LOWE OBSERVATORY. j/p LOWE OBSERVATORY. The telescope and other instruments were brought to Echo Mountain, California, and installed in the Lowe Observatory in August, 1894. They were taken from the Warner Observatory in Rochester, New York. Dr. Swift was director of that insti- tution from its foundation. The addition of electric lights to the city spoiled the definition in telescope of all faint objects in the sky. Prof. T. S. C. Lowe then secured both instruments and astronomer for Southern California. Here the air is pure and definition perfect. Dr. Swift came with all the apparatus, super- intended the erection of the observatory and the mounting of the telescope on its pier. He remained director of the Lowe Observa- tory until December 31, 1900. Many of his famous discoveries of nebulae were made here. During his long and elaborate ex- ploration of the heavens, he discovered, measured their positions, and catalogued 1302 nebulae, about half of these being discovered at the Lowe Observatory. He also discovered thirteen comets, several being detected from this mountain top. He retired laden with honors at the age of eighty-three years. The comprehensive plan of establishing a well-equipped as- tronomical observatory on the summit of Echo Mountain, at a high altitude and under the cloudless skies of far-famed Southern California in an atmosphere where clearness of vision and steadi- ness of observation could be depended upon to furnish their aid in furthering the advancement of human knowledge, is entirely due to the untiring efforts and devotion to science of a man whose name has become a household word Professor T. S. C. Lowe. PHOTOGRAPHS OF SOLAR PROMINENCES. Taken at the Yerkes Observatory by Mr. Ferdinand Ellerman. Altitude of Prominence in lower view, 185,000 miles LOWE OBSERVATORY. 321 Any handbook of the Lowe Observatory, or publication involving the scientific research of this institution, would not be complete without a sketch of this remarkable man, who at the age of seventy, when most men are wont to retire from the normal occupations of life, has been found planning for Southern California an institution of research and learning of which the Astronomical Observatory of Echo Mountain was but to be the initial step. It is to be hoped in the interests of science and in the interests of the fair name of Southern California that the plans of this institution which have been slowly but surely evolving in the mind of this great man may during his lifetime be carried to a concrete issue. In the meantime it may be truly said that he has in two ways left an indelible impress on the com- munity in which he has chosen his abode. First, through his connection with and the construction of the great engineering achievement, the Mount Lowe railway, and second, through his carrying to a successful finish, the Astronomical Observatory on Echo Mountain, which bears his name. The former marks an epoch in the material advancement of Southern California; the latter points with pride to the pari passu advancement of a love for science in our section of the country. Born in New Hampshire in the year 1832 from old New England stock, he inherited from his parents all the sturdy quali- fications for which the descendants of the pilgrims have become so well known. It was at an early age that his attention was turned to the sciences, and especially to the subject of meteorology. A ques- tion confronted him involving the probability of the existence of permanent air currents in the upper strata of the earth's at- mosphere, air currents which in his opinion must necessarily exist and be moving in a direction parallel to the earth's rotation on its axis. He gave much of his time and talent to this fascinating subject. After long and serious deliberation he concluded that 322 LOWE OBSERVATORY. the only method of solving the problem was to ascend in a balloon to an altitude above the earth's surface sufficiently high to attain the specific conditions. It was this that led Professor Lowe's attention to aero- nautics, and on the 2Oth of April, 1861, at 4 o'clock in the morn- ing we find him leaving Cincinnati in a balloon. The voyage was a remarkable one, it being not only the longest, but also the quickest aeronautic excursion on record. At noon on the same day he left Cincinnati he arrived at the Atlantic coast in the lati- tude of South Carolina. A remarkable voyage of 1000 miles had been performed in eight hours. The existence of the upper air currents became an established fact. The attention of the United States government was attracted by this remarkable feat. Professor Lowe's services were en- listed for the organization of an army balloon corps. Rapid progress was made in the improvement of balloons for war pur- poses. It was found that this service under the direction of Pro- fessor Lowe became an invaluable aid in observing the move- ments of the enemy during the civil war. At some time during the sixties he turned his attention to other inventions which have proven to be of great value to mankind. The first patents for machinery for making ice arti- ficially and for refrigerating in general were awarded to him in the year 1867. Again, the discovery of the process and method of making illuminating gas by what is known as the Lowe Water Gas Sys- tem is due entirely to his inventive genius. This system has been perfected and is in use in nearly every large city in the United States. These are but a few of Professor T. S. C. Lowe's contribu- tions to the intellectual and material advancement of his fellow- men. In times to come, generations hence, mankind will continue to benefit by the results of his scientific activity. SPECTRA OF THE; SHOWING NEW STAR IN PERSEUS, ITS EVOLUTION. PROFESSOR BARNARD'S PHOTOGRAPH OF A DENSE REGION IN THE GAI V AXY, END OF THE YERKES 40-iNCH TELESCOPE, WIIJJAMS BAY, WISCONSIN. Property of the University of Chicago. THE GREAT NEBULA IN ORION. Photograph by Professor E, E. Barnard. PROFESSOR E. E. BARNARD'S PHOTOGRAPH OF A RICH REGION IN THE MILKY WAY. e Observatory taken on a dark night by means of the Electrical Searchlight, distance, 1800 feet. Exposure 3 minutes. (Cut by courtesy of the Photographic Times Bulletin, New York.) The I,owe Telescope. Diameter of Object Glass, 16 inches; Focal length, 22 feet. Made by Alvan Clark & Sons. Cambridgeport, Massachusetts. INDEX Page Aberration of Radiance 204 Aberration and Parallax 205 Absorption Spectra 55 Absorption 57 Absorption Lines by Experiment. .53 Absolute Zero of Temperature. .. 168 Acceleration 270 Acceleration of Chaotic Moon. . . .267 Activity 275 Activity derived from Gravity. .. .276 Activity and Velocity 291 Alphabet of Nature 37 Aldebaran 215 Alpha Centauri 232-234 Amoeba Making Segmentation. . .262 Ancient Sun, The 173 Antiquity of the Universe 292 Analysis of Radiance by Means of its Spectra 44 Apioid, Poincare's 261 Apioid Sun Dividing 261 Aryans, The 284 Arc, Electric 46 Arc Light Carbons 60 Arcturus 215 Arequipa, Peru, Observatory. .. .222 Asiatic Climates 158 Astronomical Spectroscopy 51 Astrophysics 283-305 Astronomers Baffled 195 Astronomers' Early Struggles. . .194 Attraction of Electricity 286-287 Auroral Displays 143 Auroras and Sun-Spots 136 Aurora, Bock's 141 Aurora, April 16, 1882 147 Australian Graph 228 Axis of Earth Turning 315 Page Barnard, Professor E. E 220-237 Barnard's Graphs of Milky Way 237-304 Beta Lyrae 252-253 Beta Aurigse, Spectrum of 248 Bessel 206 Bessel's Parallax 207 Bhagavad Gita 284 Bigelow's Spherical Magnetic Field H5 Binary Suns 229 Bridge, Great Circular 311 Bridges Across Sun-Spots ...117-120 Bradley's Parallaxes 201 Bromide Plates 306 Building a Spectroscope 34 Building a Spectrum 24 Bunsen Burner 46 Burnham, Professor S. W 236 Byron's Last Man 274 California Climate 311 Campbell, Professor W. W.... 82-257 Campbell, Eclipse Outfit 99 Canopns 215-226 Capella 257 Carbon Photosphere of the Sun..ioi Carbon, Mystery of 101-102-105 Carbons 35-60 Carbons, Searchlight 35~37 Carbons, Arclight 37 Catalysis 173 Catalytic Activity 173 Ceaseless Records of Sun 115 Centrifugal Tendency 267 Chemism 171-174 Chemistry of the Sun 65 Cipher Dispatch from the Sun 34 330 INDEX Page Clark, Alvan 305 Climate, California 311 Climate, Mesopotamian 158 Cluster in Perseus 227 Cloud Effects 311-312 Coherer 145 Cold Light 290 Comparison of Lines 66 Congress of Astronomers 307 Contraction of Suns 293 Conservation of Areas 290 Corpuscular State of Matter 171 Corpuscles, J. J. Thomson's 17 Corpuscles, Are Probably Electri- city 17 Corpuscles, Oscillations of 29 Crooke's Vacuum Tubes 138 Curies, Discovery of Radic Activ- ity 18 Darwin, Professor George H.... 259-265 Darwin, Professor George H., Portrait 268 Dark Room 20 Day, The First 264 Dead Worlds 306 Detection of Binary Suns 246 Diffraction of Radiance. . .22-40-42-45 Diffraction Grating 39 Dispersion of Radiance 22 Discovery of Spectroscopic Bina- ries 239 Dispersion, Wide 80 Distance of Nearest Star. .213-224-225 Doolittle, Professor 168 Double Stars 236 Doppler's Effect 239 Dry Plates 87 Draper, Professor J. W 85 Draper, Dr. Henry 92 Drift of Pleiades 278 Dynamics of the Sun 161 Dynamics of Liquids 167 Earth's Place and Man's 215-293 Earth, a Particle of Dust 64 Earth Compared to Solar Explo- sions 74-75-76-77-81 Earth and Moon Inevitable 272 Page Earth and Moon Separating 271 Echoes, Remarkable 311 Echo Mountain 310 Eccentricity of Stellar Orbits 246 Eclipse, Path of Solar 98 Eclipse, South America and Africa, 94 Eclipse Showing Sun's Corona. 89-96 Eclipse of Sun 89, 95, 96-129 Edison, Thomas A 159 Effect on Earth of Jets on Sun. ..123 Effect of Tidal Friction 265 Effect, Doppler's 239 Electricity 184-284 Electricity and Magnetism 184 Electrical Induction in Primeval Nebulae 286-7 Electrical Attraction Causing Ro- tation 289 Electro-Magnetism 131 Electro-Chemism 175 Electricity, Long Distance Trans- mission 309 Electric Storm 313 Electric Inclined Railway 308 Electric Arc 46 Electric Spark 46 Energy, Late Definition of 17 Energy, Radiant 17 Energy, Transmission of 18 Energy, Seems to be Eternal 293 Energy, a Property of Matter. . . .293 Energy of Light 177 Energy, Total of Sun 170 Entropy, Running Down of Heat. 169 Engines, Three Mighty 65 Evershed, Flash Spectra 104 Evolution, Its Vast Import. .270-293 Evolution Stamped on Universe. .293 Evolution Wrought by Tides 263 Evolution of the Sidereal Universe 306 Evolution Slow 222 Evolution of the Earth and Moon. 269 Evolution Now in Activity 275 Evolution of Suns 280 Extreme Diffusion of Matter 171 Exploration of the Universe 64 Exploration of Cosmical Laby- rinths 65 Explosions on the Sun 74-75-76-77-81-88 Faculse on the Sun 117-118 Fall from an Infinite Distance. . .291 Falling Forever 291 Falling on the Sun, Velocity of.. 164 Filaments in Sun-Spots 117 First Day 264 First Month 269 Fissures in Primeval Cosmical Bod- ies 267 Fizeau b6 Fleming, Mrs., Graphic Measures. 226 Flamstead, Search for Parallax. .199 Flash Spectrum, The 100 Foucault 86 Fraunhofer's Historic Spectrum. .33 Fresnel's Mirrors 40 Fruits and Flowers 311 Friction Due to Tides 264 Friction, Effects of 265 Furrows, on Contracting Masses. 267 Future of Earth and Moon 272 Future of the Sun 274 Galvanometer 185 Galvanometer, Mirror 186 Gamma Andromeda 230 Gemmation, Deep Fact in Nature. 261 Gemmation of Apioid Suns 261 Geisler Tubes 140 Glyphs, Egyptian 317 Grand Panorama 311 Gravity, Seems to be Eternal 276 Gravity and Tides, the Builders. .275 Gravity Potential of the Sun 164 Grating, Diffraction 39-67 Grating, Ruled 14,438 Lines to Inch 39 Grating, a Mighty Engine for Re- search 65 Groombridge, the Star 1830 291 Hale, Professor George E 106 Hale's Spectroheliograph 107 Hale's Heliograph 112 Hale's Solar Prominences 113 Hale's Snapshot at Solar Promi- nence . . .112 I N D E[X 331 Page Page Hale's Composite Graph 114 Harmonics 25 Harvard College Observatory. 214-222 Harvard Collection of Negatives. 226 Harvard Observatory in Peru.... 222 Heat Running Down 179 Heat of Sun, Its intensity 117 Heat Potential of Sun. .. .155-166-179 Heat, Sources of the Sun's 162 Heat of Impact on the Sun 163 Heat and Gravity 166 Heat Potential of Velocity 168 Heat, Light, Life and Mind, Ephe- meral 275 ,*Heat, Its Dissipation in Space.... 168 Heat of Stars 192 Helium, R.amsay's Discovery of. ..283 Heliostat in the Lowe Observatory 197 Herschel Discovers Binaries 229 Helmholtz 172-178-179 Henderson, Work on Parallax. . .209 Hertzian Waves 85 History of the Sun 170 History of the Earth and Moon. .271 Hooke's Stellar Parallax 198 Huggins' Spectroscopy 87 Hussey, Professor W. J., Double Star Work 236 Hydrogen 17-280 India, Solar Eclipse in 99 Induction, Electrical, Fundamental 286-7 Induced Electricity Causing Rota- tion 289 Interference of Radiance 40 Interference or Diffraction Spectra. 41 Interminable Space 212-307 Infinite Space, Velocity of Fall from 291 Infinity, No Impress on Mind.... 291 Jets on Sun 81-123 Joule's Heat Equivalent 163 Keeler's Spiral Nebulae 285 Kelvin, the Physicist 281 Kepler's Third Law 232-252 Kepler's Spectrum 32 INDEX Page Kinetic Theory of Matter 163 Kinetic Energy, Law of 163 Kirchhoff 22 Kirchhoff's Law 23-27-56 Kirchhoff 's Original Work.. 54 Langley, Professor S. P 149 Langley's Account of Aurora. ... 149 Langley, Measurement of the Sun's Energy 157 Langley, Measurement of the Sun's Heat 117-181 Langley, Spectro-Bolometer. .182-187 Langley, New Spectrum 189 Langley, Holograph 196'- Langley, Energy Spectrum 191 Langley, Bolometric Spectrum. . . .182 Langley, Drawing of Sun-Spot. .. 122 Lantern, Electric 49 Lane's Law 180 Law, Kirchhoff's First 23 Law, Kirchhoff's Second 27 Law, Kirchhoff's Third 56 Law, Lane's 180 Law of Kinetic Energy 163 Law, Mathematical and Physical. .260 Law, Kepler's Third 232-252 Law, Stefan's 180 Law of Velocity 163 Law of Conservation of Areas. . . .290 Law of Variation of Light 153 Lick Observatory Eclipse Expedi- tion 100 Ligament, between Earth and Moon 272 Light Waves 20 Life a Late Product of Matter. .307 Life a Mere Episode 274 Life Ephemeral 274 Lockyer's Apparatus 61-63 Lowe Observatory 296 Lowe, Professor T. S. C 307 Magnetism and Sun-Spots 150 Magnetic Field 125-133 Magnetic Induction 131 Magnetic Storm 125-134 Magnet, The Sun a Spherical. 144-145 Matter, Kinetic Theory of 163 Matter, Wide Diffusion of 171 Page Matter, Phases of 36 Matter, Phases of, in the Sun 68 Matter Stored in Dead Worlds.. 307 Matter, Quantity of 291-292 Matter Seems to be Eternal 276 Matter, Primordial State of 171 Matter, Corpuscular Jji Mars, Moons of 273 Mass of the Universe 292 Mass of Binary Suns 232-251 Mass of the Sun 292 Mass of a Corpuscle 18-280 Maury, Miss, Measurement of Graphs 226 Men, Pale and Faint 285 Meridian Photometer 153 Meteoric Shower 315 Meyer's Concept of Beta Lyrae...253 Mechanics of Tides 266 Micrometer 195-196 Micrometer, Field 198 Micrometer, Screw 183 Mind, Last Refinement of Matter. 293 Mind, Ephemeral 307 Mills' Spectrograph 241-242-245 Modes of Matter in the Sun 68 Molyneux 201 Motor, the Solar 159 Motion of Stars in the Line of Sight 244 Motion, Proper, of Stars 277-8 Motion of Pleiades 278 Nearest Neighboring Sun. .. .195-224 Nebulae 279-280-281 Nebulae, Spiral 285 Nebulae and Suns in Evolution. . .282 Negative Ions 18 Negatives at Harvard 226 Nerve, Platinum 26 Newcomb, Professor Simon. .219-257 Newton's Spectrum 32 November Meteors 315 Nova Persei 285 Number of the Lucid Stars 214 Observatory, the Lowe 296 Observatory, the Lick 100 Observatory, Harvard College 122 Observatory, Yerkes 215 Page One Hundred Million Suns 219-222-292 Orbits of Binary Suns 246 Outlines of Spectroscope 45 Outfit, Lick Eclipse 99 Palace of the Universe 223 Panorama, Grand 311 Parallax of Stars 194-200 Parallax of Alpha Centauri 209 Parallax, Bessel's Method 207 Parallax, Cassini's Attempt to Find 2OO Path of Solar Eclipse 98 Path of the Sun in Space 282 Pelton Water Wheel 310 Perseus, New Sun in 285 Phases of Matter in the Sun 68 Photography, Astronomical 222 Photography, a Majestic Science. .222 Photography of All the Stars. 216-307 Photography of the Sun 85-88 Photography of Eclipses 99 Photography of the Spectrum 71 Photography Stores Knowledge for the Future 293 Photography of Milky Way. .220-237 Photography of Nebulae 285 Photosphere of the Sun, the Car- bon 101 Photometer, Meridian 153 Plan of Palace of the Universe. .223 Platinum Nerve 26 Plastic Suns Passing in Space... 260 Plumbline Sunk in Space. ....... .260 Plutarch Mentions Sun's Corona.. 93 Poincare's Apioid 261 Polaris 257 Polarity 175 Potential of the Sun 151 Potential of Velocity 161-164 Potential of the Universe 291 Primordial Electrical Induction... 286-7 Primordial Cosmical Mass 281 Primordial State of Matter 171 Primordial Tides 263 Prism 39 Prismatic Telespectroscope. . . .80-256 Prominences on the Sun. . . .81-88 INDEX 333 Page Prominences Hydrogenous 88 Prominences Seen Without an Eclipse 91 Proper Motion of the Stars 277 Profound Solitude 315 Pyroheliometer 156 Pyramid of Sulphis 308 Quantity of Heat of Sun 178 Quantity of Matter 291-292 Quadrillions of Dead Worlds. .. .292 Quadrillions of Miles 281 Radian, A 210 Radiant Energy Defined 17 Radiant Energy and its Fixation. .84 Radiant Sun, the 117 Radio-Activity 18 Radium 18 Railway, the Inclined 308 Ramsay, Approach to Absolute Zero 109 Ramsay, Discovery of Helium. 95-283 Rarity of Primordial Matter. .171-308 Records, Ceaseless Photographic. .115 Reservoir at Observatory 310 Reversal of Spectrum Lines 67 Roemer, Velocity of Light 202 Roentgen Waves 85 Rotation, Caused by Electrical In- duction 286-7 Rubio Canyon 310 Russel, H. N 257 Scale Applied to Spectra 58 Searchlight on Echo Mountain, 3,000,000 Candle Power 37 Secchi ..82 See, Dr. J. J. T 168-172-259 Sidereal Structure, the 212 Sidereal Sheets 299 Silence Profound on the Moun- tains 315 Sirius 215-254-253 Slit of Spectroscope 31 Slit for Solar Work 72 Smith, Misses Jennie M. and Ma- tilda H 30 334 INDEX Page Solar Activity 84 Solar Brightness 154 Solar, Constant, the 157 Solar Dynamics 161 Solar Eclipse, Path of 98 Solar Eclipse Outfit, Campbell's. . .99 Solar Eclipse, Thwaite's Graph of ; 105 Solar Gravity Potential 167 Solar Heat, Sources of 162 Solar Heat Potential 166 Solar Jets 81 Solar Light 154 Solar Motor 159 Solar Origin 293 Solar Photograph, Janssen's 92 Solar Prominences 74-5-6-7-81-88 Solar Prominences, Hale's 113 Solar Spectroscopy 91 Solar Spectroscope 70-71 Solar Spectrum 22 Solar Spots.. .116-118-120-122-126-127 Solar Spots, Langley's 122 Solar Spots and Auroras 136 Solar Chemistry 65 Solar Corona 89 Solar Potential 151 Solitude on the Mountains 315 Space, the Standing Mystery 283 Spectrum Analysis 23 Spectroscope, The 29-30-48 Spectrograph, the Lowe 71 Spectro-Bolometer 182 Spectro-Chemistry 52 Spectrum, the Flash 100-104 Stars, the 192 Stellar Evolution 258 Stellar Parallax 200 Stellar Universe 221 Stellar Motions 277 Storm, Great Electric 313 Sun's Duration of Activity 179 Suns Flying at Random 259-277 Summary 293 Page Telespectroscope, the Lowe 71 Terminal Velocities 172 Terrestrial Influence of Sunspots.i3o The Ancient Sun 173 The Aryans 284 Thomson, Professor J. J. .17-108-280 Tides 265 Tidal Evolution 265 Tides Made the Earth and Moon265 Universe, Exploration of 64 Universe, 30,000 Light Year Diam- eter , 281-291 Universe, a Growth 306 Universe, Renewal of 307 Useless Years 274 Vacuum Tubes 138-140 Velocity, Potential, of Sun. .. 161-164 Velocity, Potential, of Universe. .291 Vista, the Grand 311 Voices of the Night 317 Vogel's Graphic Telescope 2^/1 Vogel's Spectrograph 256 Waves, Types of 19 Wave Motions 19 Wave Lengths 24 Waves, Hertzian 85 Waves, Roentgen 85 Wave, One 294 Wave Fronts, Leaving Grating... 39 Wilcox, Ella Wheeler 200 Willard Lenses 220 Waste Products of the Universe. .275 Whirlpools in Primordial Nebulae 290 Worlds Clutched by Tides 273 Worlds in Final Collision 294 Worlds, Dead, More Than Living 292-306 Young, Professor Charles A 68-87-103-109-125-128-155 Young, Anna Sewell 179 ERRATA. Cuts 42, page 105, are misplaced. Upper should be lower. Cut 46, page 112, is bottom up. Cut 60, page 140, Crooke's Tubes, should read: "Geisler's. OF THr. UNIVERSITY OF ^ AD VERTISEMENT 335 PACIFIC ELECTRIC RAILWAY COMPANY MOUNT LOWE DIVISION H. E. HUNTINGTON PRESIDENT EPES RANDOLPH VICE-PRESIDENT C. W. SMITH SECOND VICE-PRESIDENT W. H. SMITH MANAGER PASADENA AND MT. LOWE DIVISION H. F. GENTRY GENERAL PASSENGER AGENT H. F. STEWART ADVERTISING AGENT J. F. TURNER, SUPERINTENDENT MT. L,OWE DIVISION UNIVERSITY OP CALIFORNIA LIBRARY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW <;;#. APR 10 DEC 14 DECEIVED BY JUN 191987 (tlRCULATlON DEPT, 19Jun'57Bg RECTD LD DEC LIBRARY USE ONlY !JUN 19 CIRCULATION 30m-l,'15 I OU7 / V / 175084