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the south (the sixth ridge of Schroter). On its place is a round spot of light more than two that date there was not the slightest indication miles broad, extremely brilliant, which has of a shallow crater, nor the least appearance in quite the character of the spot Linné and of the the surface round the cone which might be few others of this kind which are found on the considered indicative of its becoming a white moon. The small crater south of d, which spot as the sun rose above it. The termina- Mädler gives, is still distinctly visible. Schrotor was a little east of the cone, and the next ter has nothing about this spot of light. Lohrridge beyond the cone toward the east was be- mann's (unedited) plate gives a very large spot, coming visible. Mr. Huggins, Mr. Carpenter, almost 2° in magnitude, and a very small hill and Mr. Penrose observed Linné the same inside of it. Herr Schmidt sent to Mr. Birt evening, with the same results obtained by Mr. three sketches, the first from Mädler, the secBirt. Mr. Carpenter also gives the crater open- ond from Lohrmann, and the third his own. ing on the cone. Rev. T. W. Webb made ob- Mr. Birt took an early opportunity to examine servations confirming those of the other gen- the region of the supposed change. Schmidt's tlemen. The portion of the Mare Serenitatis sketch was found to be a faithful representaon which the cone was seen is so surrounded tion of the spot, with perhaps the exception of by ridges as to be easily taken for a large shal- the white spot being better defined and in low crater, and it may be that some of the dis- more striking contrast with the surface near it. cordances between observers may be thus ex- Two friends, who were with Mr. Birt at the plained. Mr. Birt remarks that we are greatly time, bore testimony to the accuracy of ignorant of the true nature of the moon's sur- Schmidt's sketch. Mr. B., of course, failed to face. The extent of our knowledge appears identify the features depicted by Lohrmann to be of a twofold character: First, we per- and Mädler. ceive differences of color and brightness, from Mr. W. R. Birt communicated a paper to the which we infer that the surface consists of dif- meeting of the Manchester Literary and Philoferent materials reflecting different degrees of sophical Society, giving an account of a new light, and also of tint. Second, the presence variable spot on the moon's surface, which exof shadow reveals to us manifest irregularities hibited similar phenomena to those of the of surface as regards level, elevation, and de- crater Linné. The observations were made by pression. With the nature of the surface Rev. W. 0. Williams, of Pwllheli, who had beyond these two characteristics we are un- undertaken the examination of a zone on the acquainted, and can only trace out slowly moon's surface, of 2° of latitude, from 4° to 6° certain analogies with phenomena that are south. The spot in question was situated on familiar to us on the earth's crust.
the south western side of the ridge forming Other supposed Changes in the Moon.-Herr the northeastern boundary of Hipparchus. J. F. Julius Schmidt, Director of the Athens Its diameter is 59.94, and magnitude 0°.37, the Observatory, notified' Mr. Birt, in June, of his diameter of Dionysius being regarded as unity. discovery of another supposed change on the On De la Rue's photograph, February 22, 1858, moon's surface. The region of the phenome- it appears as a spot of about 4° of brightness. non is situated easterly, near Alpetragius. At It is not so bright as Linné, which is about 5o. this point Mādler in his Atlas has a crater al- On Rutherford's photograph it appears brightmost a mile in diameter, and says, "in the fars' er than in De la Rue's, namely, 5°—Linné thest east shines also, with a light of 8°, the being 6° in the same photograph. The obsmall crater d.” This crater d, Herr Schmidt servations alluded to by Mr. Birt are as folproceeds to say, now no longer exists, but, in lows:
Brightness. 1858 February 22.
De la Rue, Ph. A bright spot. 1865 March 6.
Rutherford, Ph. A bright spot.
" A faint shallow crater. 1867
Ingall, " Drawn as a crater. 1867
17 13 to 15. Williams, “: A very conspicuous crater.* 1867 18 17 to 19... Williams, Crater very conspicuous, with a small central
cone casting a shadow. 1867 November 5 9 to 10... Williams, " Very bright, a streak of interior shadow
on the west. 1867 6 8 to 10... Williams, “ A bright patch of light, streak of shadow scarcely discernible.
6° 1867 15 18 to 20... Williams, “Very bright.*
10° 1867 December 5 6 to 8... Williams, 6 A whitish spot, no trace of a crater. 1867
6 9 to 10... Williams, A whitish spot, no crater.
Mr. Baxendell states that on the night of achromatic of 74 inches aperture, using powthe 3d of January, 1868, he had an opportunity of examining the spot referred to by Mr. Birt, point to the east, which he considered to be the highest ers from 60 to 250. It was then a well-marked the time of minimum heat in the moon. Exthough shallow crater, having a diameter periments to test the heat of the moon have abont three-fourths of that of Beer and Mäd- been made by Prof. C. P. Smyth, at Teneriffe. ler's Hipparchus F. The shadow of the He found that it amounted to no more than western wall was very conspicuous on the would be given out by the heat of a waxfloor of the crater.
* On these occasions Mr. Williams saw a small bright with Mr. Gladstone's equatorially mounted point of the ridge:
candle at a distance of fifteen yards. Mr. In a paper read before the British Associa- Harrison shows that this was not the right tion, Baron von Mädler makes a few sugges- time to have expected to discover heat from tions to moon-observers. He calls attention to the moon; that at the time when most heat certain straights of light which only show was really given out, the effect upon the themselves in high sun illumination; of these earth's surface was, that a lowering of the nothing is known, except that they are by no temperature was produced. Mr. Harrison remeans elevations. Ridges of only 500 feet fers to the tabulated results of temperature at high are to be recognized through this shadow Oxford, Greenwich, and Berlin, taken for near the light edges; but these straights never several years, which agree in proving that, at show the smallest shadow, and vanish in the the time when by calculation the moon must vicinity of the light edges. They proceed in have acquired the greatest heat, the average a radiating manner from single bright Ring- temperature of the earth's surface was lower, mountains, especially from Tycho, Copernicus, accompanied by a dispersion of cloud. Kepler, Byrgins, Aristarchus, and Olbers; Solar and Planetary Tables.- The Royal from some other Ring-mountains they pro- Astronomical Society of England, at their ceed only from one side, as from Menelaus annual meeting in February, awarded the and Proclus. By a superficial observation gold medal to M. Le Verrier for his solar and they may easily be confounded with the planetary tables, which include Mercury, mountain veins, but an attentive examination Venus, the Earth, and Mars, and have superwill remark essential differences between seded others for calculating the places referred them. The easiest to observe is the light to. straight which divides the Mare Serenitatis Secular Variation of the Elements of the almost equally in halves. He had observed Earth's Orbit.—Mr. John L. Stockwell comthis several times for shadow, but could never municated to the American Journal of Sciences detect the smallest. The author alludes to for July an interesting paper on the “Secular the rills on the moon's surface, as objects Variations of the Elements of the Earth's Orwhose variability, probably, does not depend bit” (see ANNUAL CYCLOPÆDIA, for 1867, art. on our atmosphere, but is to be referred to ASTRONOMICAL PHENOMENA AND PROGRESS), real changes. He had sought for two years Mr. Stockwell furnished a table, appended in vain for the southwest continuation of the hereto, based upon data and formulas more Ariadæus rill, though its existence came to fully given in his treatise on the “Secular his knowledge from other quarters—till, un- Equations of the Moon's Mean Motion.” The expectedly, he obtained sight of it in 1833. He materials used in the preparation of the formulas remarks that it is advisable to observe on the are those used in the construction of the Amersame evening, not merely a single rill, but ican Ephemeris and Nautical Almanac, with many somewhat similar ones; for as the the exception of the mass of the earth, which earth's atmosphere must exercise a like effect has been increased to us. The contents upon them all, so would a perceptible varia- obtained by Mr. Stockwell differ somewhat tion present us with a hint for further investi- from those given by Le Verrier in his Memoir gations.
on the Secular Inequalities of the Seven PrinHeat gicen out by the Moon.—Mr. J. P. cipal Planets, not only on account of the disHarrison, in a paper read before the Royal turbing influence of the planet Neptune, which Astronomical Society, takes the ground that the had not been discovered at the time of his inheat acquired by the moon, and radiated to vestigation, but also on account of the improved the earth, is what Prof. Tyndall calls “ dark values of the masses and elements of the other heat," or what would be almost wholly ab- planets. The superior limit of the eccentricity sorbed by our atmospheric vapor. This would of the earth's orbit, which Le Verrier gives as raise the temperature of the air above the equal to 0.07775, should be reduced to 0.06939, clouds, increase evaporation from their surface, and an increase of the mass of the earth, cordiminish their density, raise them to a higher responding to the latest determinations of the elevation, and under favorable circumstances solar parallax, would reduce the value of the disperse them. In either case, a sensible fall superior limit still more. would take place in the temperature of the air În Mr. Stockwell's treatise on Secular Equanear the ground. This occurs at the period of tions, etc., already referred to, he gave a table lination when the moon has acquired the and 'chart showing the eccentricity of the Greatest amount of heat it can receive from earth's orbit during the period of a million of the son, which is when the half-moon then years; and the table here presented is merely illuminated has been subjected to solar radi- an extension of the former one. The first date ation for about 265 hours, or at the third or in the following table corresponds to 1,175,566 last quarter. Opposite results will occur at years before the year 1850, or to 1,100,000
Eccenof Perigee. tricity.
Longitude of Perigee.
1090000 1080000 1070000 1060000 1050000 1040000 1030000 1020000 1010000 1000000 990000 980000 970000 960000 950000 910000 930000 920000 910000 900000 890000 880000 870000 860000 850000 810000 830000 820000 810000 800000 790000 780000 770000 760000 750000 740000 730000 720000 710000
years before the epoch of the integral in the interpreted by calculators. He has found that treatise mentioned. From Mr. Stockwell's cal- when those observations are compared toculations, it appears that, if at any epoch there gether, which are really comparable, the reis a maximum or minimum of any given mag- sult is that the sun's horizontal parallax is nitude, in 1,450,000 years before or after hat 8”.91, very closely agreeing with that derived epoch, there will be a corresponding maximum from the observations of Mars, in 1862. The or minimum. A computation similar to this, mean distance of the sun, deducible from this prepared by Mr. James Croll, and published in parallax, is 91,740,000 miles. That which is the Philosophical Magazine, for February, deducible from the opposition of Mars (sun's 1867, was based upon Le Verrier's formulas: parallax 8".94) is 91,430,000. The transit of Table showing the Elements of the Earth's Orbit during Venus in 1882 will afford a most favorable opa period of one million of years.
portunity to estimate the distance of the sun; better than the transit which 'will occur in
Asteroids.-Reported discoveries of new mi-1100000
nor planets during the year brought up the 11° 54' 0.02130
35° 49' 0.03679
whole number now known to 106. M. Coggia,
at Longchamp, Marseilles, discovered No. 96 0.01203 February 17th. On the same night, M. Tempel, 0.01628 of Marseilles, added another to the list, No. 97, 0.02962 and named 'it Clotho. M. Tempel requested 0.04892 the finders of the next two planets to accept for 0.05324 them the names Lachesis and Atropos, in order 0.05241 0.04629
that the three sister Parcw might together 0.03572 complete the first hundred of the planets.
When Le Verrier announced to the French 0.00157 Academy of Sciences the discovery of planet 0.00883 96, M. Delauny took exception to the repre0.03328 hensible practice of withholding the names of 0.04034 the subordinates in government observatories
by whom discoveries of comets and planets may 0.05807
0.03866 be made. He added that the discoverer of
planet 91 (Ægina) was M. Borelly. Profes
sor Watson has named two planets discovered 0.01027 by him in 1867 as follows: 93, Minerva, and
94, Aurora. To the United States belongs the 0.01970 honor of finding the majority of the new plan
ets of 1868. On the 18th of April, Professor 0.01815 O. H. F. Peters, of Clinton, N. Y., discovered
98. Its situation was reported as follows:
Ham, Coll. M. T.
Planet 99 was discovered by M. Borelli, at Mar700000
0.02190 seilles, on the 28th of May. His observation
-9° 5' 49.1
Professor James O. Watson, of Ann Arbor, 0.04204 Mich., discovered No. 100 July 11th, and named
0.03669 it Hecate. It shone like a star of the 10th magDistance of the Sun.-The problem of the 101, and gave it the name of Helena. Ele
nitude. On the 15th of August he discovered sun's distance has lately been reinvestigated by Mr. Stone, first assistant of the Royal Ob- ments of the two planets furnished by Professervatory, Greenwich. He has found that
sor Watson to the American Journal of Science
are as follows: previous calculators, including Encke, have fallen into some mistakes in their use of the
Hecate (100) recorded observations of the transit of Venus. Epoch = 1868, Sept. 1.0 Washington M. T. In consequence of the effects of irradiation of the sun's light as the planet passes on and off
0.5 his disk, the phenomenon is somewhat compli
X = 128 28 37 7 Ecliptic and mean equinox 1868.0. cated, and discoverers made use of different terms in describing it. Some of these expres
log u = sions, according to Mr. Stone, have been mis
-590000 76 12 0.01066 580000 184 11 0.01150 570000 216 2 0.02104 560000 287 10 0.02922 550000 327 32 0.03397 540000
8 40 0.03509 530000 52 40 0.03327 520000 101 40 0.03013 510000 155 8 0.02915 500000 208 31 0.03085 490000 256 41 0.03 130 480000 299 120.03734 470000 337 57 0.03733 460000 14 16 0.03100 450000 49 32 0.02697 445000 86 8 0.01663 440000 149 7 0.00452 430000 303 11 0.01147 420000 342 13 0.02593 410000 14 42 0.03941 400000 45 44 0.05055 890000 76 12
380000 106 22 0.06099 370000 136 17 0.05862 360000 163 48 0.05083 350000 194 7 0.03800 340000 217 25 0.02138 330000 183 19 0.006 10 320000 134 54 0.02014 310000 158 20 0.03834 300000 172 38 0.05309 290000 218 0.06263 280000 249 35 0.06592 270000 281 39 0.06275 260000 314 22 0.05369 250000 348 7 0.04000 240000 25 2 0.02358 280000 85 51 0.00737 220000 233 49 0.01181 210000 279 9 0.02496 200000 315 6 0.03.160 190000 349 43 0.03990 180000 24 42 0.04079 170000 61 24 0.03789 160000 94 17 0.08188 150000 148 35 0.02651 140000 204 37 0.02305 130000 262 47 | 0.02 137 120000 313 18 0.02883 110000 356 27 0.03318 11-100000
0.03199 0.02380 0.01553
0.01977 0.02129 0.03021 0.03520 0.03740 0.03594 0.03056
41 15 71 30 96 11 101 86 63 47 61 29 81 16 106 41 130 55 155 39 184 52 200 31 219 14
690000 680000 670000 660000 650000 640000 630000 620000
610000 - 600000
135 21m 79.92
M = 10 5 30.4
6 33 34 .6 8 39 32.5 0.493331 2.810010
14 14 16.93
of compound prisms, which gives a dispersive power equal to nearly seven
prisms of 60° of Epoch = 1868, Sept. 13.5 Washington M. T. M= 19 4 531.0
dense flint glass, Mr. Huggins has been makT= 298 40 51.0
ing a new series of observations on heavenly = 343 5 0 1 Ecliptic and mean equinox 1868.0. bodies. His conclusions with regard to Sirius
4 19.5 8 0 48 1
are specially interesting. He is of the opinion log a=
that the substance in that star, which produces log u = 2.934317 = 858"640
the strong lines in the spectrum, is hydrogen; No. 102 (for which the name of Miriam is pro- also that the aggregate result of the motions posed) was discovered by Dr. O. H. F. Peters, of the star and the earth in space, at the time at Hamilton College, August 24th. It was in the observations were made, was to degrade the constellation of Pisces, and had, at three the refrangibility of the dark line in Sirius by o'clock of that morning, 18° 38' of right ascen
an amount of wave length equal to 0.109 milsion, and 12° 54' declination, moving slowly to lionth of a millimetre. Taking the velocity of the east, and equal to a star of about the i1th light at 185,000 miles per second, and the wave magnitude. Observations were taken by the length of the dark line at 486.50 millionths of discoverer September 13th and 14th, with the
a millimetre, the observed alteration in period following result:
of the line in Sirius will indicate a motion of
recession, between the earth and the star, of Clinton M. T. (102)
41.4 miles per second. At the time of obser1868. Sept. 13, 121 482 80
+12° 8 603 vation, that part of the earth's motion which 14, 13 17 23
12 3 57 1 was in the direction of the visual ray was equal Professor Watson calculated the elements of to a velocity of about twelve miles per second this planet in the following October, and found from the star. There remains unaccounted for, them to be:
a motion of recession from the earth amount
ing to 29.4 miles per second, which the author Minor Planet (102).
feels entitled to attribute to Sirius. He refers Oct. 11, 116 54 10- 05 57 22.67 + 8° 43' 46":4 to the inequalities in the proper motion of Siri12, 10 53 37 0 56 42.78 + 8 35 15.7
us, and remarks that, at the present time, the September 7th Professor Watson added an
motion of the star in declination is less other planet to his catalogue. The following than its average amount by nearly the whole were his observations:
of that part of it which is variable, which cir1868. Ann Arbor N. T.
Comp. cumstance may show that a part of the motion Sept. 7, 152 312 463
of the star is now in the direction of the vis9,14 45 42 0 20 53.94 10, 9 59 59
Observations of Nebulæ.—Mr. Huggins has The planet is of the 10th magnitude.
applied his new spectroscope with some sucPlanets 104, 105, and 106, successively dis- cess to the study of a large number of nebulæ. covered by the indefatigable Professor Watson, About one-third of them give a spectrum of were thus reported on by him to the American bright lines. The spectrum of the great nebJournal of Science :
ula in Orion was carefully examined by sevCommunicated September 14th. I have the pleas- eral methods of comparison, with the spectra ure to send you the following observations of a new of terrestrial substances. The coincidence of planet which I discovered last night:
the lines with those of hydrogen and nitrogen, 1968. Ann Arbor M. T.
& Comp. *
remained apparently perfect with an apparatus Sept. 13, 11) 352 Go (200 25.61 20 23.65 -1° 10 521.6 7 in which a difference in wave length of 0.0460
of a millimetre would have been detected. 13, 15 55 57
These results increase greatly the probability Daily motion, -45: A--5'. The planet is of the 11.5 magnitude.
that the lines are emitted by nitrogen and hyI have yet to add that I discovered still another drogen. Mr. Huggins regards it as a question planet on the 16th October, of which I have observed of much interest whether the few lines of the the following places:
spectra of the nebulæ represent the whole of Ara Arbor H. T.
the light emitted by those bodies, or whether
those lines are the strongest lines of their spec1868. Sept. 16, 161 3a 15 Ob 13m 47.42 + 6* 1V 4.9 16, 16 33 22
8 li 45 :: tra which have succeeded in reaching the 17, 10 29 16
earth. He supposes that, since the nebulæ are Communicated October 13th. I have observed the bodies that have a sensible diameter, and in all following places of a new planet discovered by me on probability present a continuous luminous surthe 10th inst. :
face, no lines have been extinguished by the Ann Arbor Y. T.
effect of the distance of the objects from us; 1868. Oct. 10, 10- 36 37
and he suggests that, if we had reason to be10 21.84 + 0° 31' 42.5 11, 11
0 28 31 .0 lieve that the other lines which present them12, 10 26 52 0 59 48.72 +0 25 31 .2 selves in the spectra of nitrogen and hydrogen The planet resembles a star of the 10th magnitude. were quenched on their way to us, we should
The Motion of Sirius in Space. With the have to regard their disappearance as an indicaaid of a new spectroscope, consisting in part tion of a power of extinction residing in cosmical
0 220 13.18
-3° 49' 51".3
3 47 .0
0 20 20.66
13. 12 35 52 13, 13 1 33
4 020 22.56 1 10 48 .0 2 0 20 17.33 -1 11 23 .7 10
0 13 46.28
space, similar to that inferred from theoretical bution of matter or of temperature in the different considerations by Chéseaux and afterward sup
regions. ported, on other grounds, by Olbers and the type belong to variable stars. The representative
Thirdly, all the spectra of the third and fourth elder Struve. The author concludes that, at of these is the wonderful (Mira) Ceti. This has been the time of his observation, the nebula of carefully examined and found that, even when it is Orion was not receding from the earth with a only of the seventh magnitude, it has the same spec velocity greater than ten miles per second; for trum.as the typical, but only reduced to its few this motion, added to the earth's orbital ve- Tauri or Aldebaran, and Antares, this year appeared to
bright lines ; a Orion is in the same condition, a locity, would have caused a want of coincidence be smaller and of a more red hue than in the past year, of the lines of the spectrum that could have and in the first appeared traces of columns which been observed.
were not seen the year before ; so that it is evident Suspected Change in a Nebula.—The Rev. that the change of these stars depends on a periodi. H. Cooper Key, of England, has been making not so, however, with Algol, which has the very same
cal change which happens in their atmosphere. It is observations on the nebula, 45 Herschel
, spectrum of the first class or type in every stage of IV Germinorum, with a silvered glass spec- greatness ; which induces me to believe that there ulum of eighteen-inch aperture, and ten feet the variation is produced by the passage of an opaque focal length, using an eye-piece giving
body passing between us and the central star, giving
power thus an example of eclipse of a fixed star, by his of 510. This nebula presented to the Her- own obscure planet. schels a uniform nebulous disk, with a stellar Finally, a very delicate question I propose to mycentre; Lord Rosse saw one ring only; in Mr. self to be resolved by spectral analysis ; this consists Key's telescope, two rings were
distinctly vis- from the dispiacement of the lines, which ought to ible. Mr. Huggins considers the observation take place in the spectrum by the combined motion of important, as showing a definite change in the star and the propagation of light. From this new these objects; the central star of the nebula kind of aberration it would be easy to ascertain if a gives a continuous spectrum, and possibly the star has a motion whose velocity should be five times luminous
haze surrounding it also; but of Lyræ, examined in this manner, has not given any that Mr. Huggins is not so certain, the difficulty such displacement, so that it appears not to have such of getting spectrum observations of such faint a motion. In some other stars I have found that objects is so great.
there is a little displacement, as in Ursæ Majoris, but Stellar Spectra.-Father Secchi has com
this seems especially due to the different breadth of municated to the French Academy of Sciences spectrum. I have employed for this study the
the hydrogen line in the star and in the compared some further observations on stellar spectra, parison of the direct image of the stars with its own made by means of a new spectroscope, with spectrum, but I have found no such quantity of dis& cylindrical achromatic eye-piece. He con
placement. cludes that, 1st, red stars have generally spectra A New Comet.-A new comet (II. 1868) was of the third type; when the color is pale, it discovered . June 13th, by Dr. Winnecke, at may be referred to an intermediate place be- Carlsruhe. It was also independently discor. tween the second and third; 2d, a great num- ered, the same night, at the Marseilles obserber of these stars have their spectra perfectly vatory. The next night, several astronomers, resolvable into columns which are afterward to whom the discovery had been communicated, themselves resolvable into finer lines. There observed the comet, and described it as very are many others that cannot be resolved into bright and having a tail
. On the 20th, the tail secondary lines, on account of the faintness, was more than 3° in length. About that time but of which the principal lines indicate the the comet was just visible to the naked eye, type; 3d, the stars which cannot be referred and, when brightest, was comparable to a star to the three established types are very rare. of the fifth magnitude. It passed its periheSome of the author's speculations and sugges- lion, June 26th ; its distance from the sun being tions are interesting. He says:
then about six-tenths of that of the earth. It We have, therefore, without doubt, in the heavens within about 56,000,000 miles of us. Early
was nearest the earth, June 30th, and was then a grand fact, which is the fundamental distinction of in July it gradually ceased to be visible. the stars in a small number of types, which opens the field to very many cosmological important spec- The Spectrum of Comet II., 1868.-Mr. ulations.
Huggins, the industrious and skilful observer Secondly, another grand fact, which was brought of the spectra of astronomical bodies, made a out from those researches, was, that the stars of the careful study of the spectrum of comet II., of of the heavens, so the white stars are thickly gath- the past year. The results he communicated ered in the Leo, in the Ursa Major, in Lyra, Pleiades, to the Royal Society in July. He describes the etc., while the yellow ones are very frequent in Ce- appearance of the comet in the telescope, June is very remarkable for having all through, and in the 22d, as a nearly circular corona, which became neighborhood, green stars of the first type, but with rather suddenly brighter toward the centre, very narrow lines and with scarcely any red color. It where there was a nearly round spot of light. seems that this particular kind of star is seen through A tail was traced for almost a degree. The the great mass which constitutes the great nebulæ
of light of the comet, examined with a spectroOrion, whose spectrum may contrast with the primi- scope, furnished with two prisms of 60°, was us to be affected by this influence. The distribution resolved into three broad bright bands. In of stars seems to indicate in space a particular distri- the two more refrangible of these bands, the