means of predicting others, and bringing the succession of phenomena under the domain of cause and effect.

The first hint, then, that we offer to owners of small telescopes is to use them-to observe with the view of making their observations in some measure subservient to the progress of science; for if carefully used, with the most scrupulous attention to the fidelity and greatest practicable accuracy of the observations, we assure them that even small instruments may be made really to contribute thereto, and this in ways and when employed on objects which perhaps at the time inspired no such hope.

In a short paper like the present it is of course impossible to enter in any detail into the nature of the observations which may be attempted of different objects in the heavens. For full advice on this matter we must refer the reader to the Rev. T. W. Webb's admirable little work, Celestial Objects for Common Telescopes;' but it is possible that some succinct remarks on a few points may be found of value to amateurs in possession of telescopes three or four inches in aperture (that is, effective diameter of object-glass).

A very principal object of attention to the astronomer is the sun. It cannot but be that that body, which is of such indispensable importance, not merely to the life which is contained in our system, but to the very existence of the system itself, should excite in all minds capable of intelligent reflection the most lively interest as to its constitution, and the source of its light and heat-giving powers.

'Informer of the planetary train,

Without whose quick'ning glance their cum-
brous orbs

Were brute unlovely mass, inert and dead,
And not, as now, the green abodes of life.'

A field of study of vast extent still lies before the astronomer here. Much has been done in acquiring some knowledge of solar physics during the last few years, but we are still in the infancy of the subject. In this place we can of course merely suggest a few matters of

consideration to the amateur observer. In the first place we must caution him to be very particular in the use of a coloured glass to take off the intense glare and heat of the sun's rays, concentrated by the lenses of his telescope. Fog or thin cloud will indeed frequently act as a most efficient protector in this respect, but if trusted to without the aid of a dark glass close at hand, the sudden breaking forth of the sun in full blaze will sometimes produce unpleasant consequences. Indeed a person at all unpractised had better make it a rule never to look at the sun without the intervention of some kind of coloured glass. The shade and depth of this will vary according to circumstances. From his own experience the writer would recommend green as the most usual colour. Red may be employed when the sun is not shining very brightly. With regard to the time for observing the 'greater light,' there is none so good as early morning, when it has been up about an hour or so. The

definition of objects on the surface is much superior to that at any other time in the day; but of course in watching the motions and changes of the spots it is necessary to observe from time to time throughout the day. This is frequently very interesting, and, assiduously followed up, may lead to still further knowledge than has yet been attained concerning those phenomena. The periodicity also in the number and magnitude of the spots has, it is well known, led to some very remarkable consequences, and illustrates in a striking manner the advantage which accrues to science from an amateur selecting some definite object of research, and perseveringly following it up till some positive conclusion is arrived at. We may remark that, although the length of the period has been pretty satisfactorily established as 11 years, yet there are some other points connected with the law of periodicity still requiring to be decided, and in which amateurs may do good service. Inequalities between the intervals separating two consecutive times of greatest and of

least abundance are said to have been made probable. The present year is one in which the spots are approaching their time of greatest frequency and abundance.

Next to the sun we may devote a few words to the moon. She is not, indeed, of the same importance to us as he is, but in very many ways we could very ill afford to part with her, who

A smaller earth, gives us his blaze again,
Vold of its flame, and sheds a softer day.

Besides the advantages of moon-
light, attended, like all the advan-
tages of nature, with so much to
gratify our innate love of the beau-
tiful, she is (thanks to the long
series of valuable lunar observations
made at the Greenwich Observatory
during the last two hundred years)
of the greatest utility to navigation
in enabling us by her position
amongst the stars to determine the
position of a ship at any time in
mid-ocean. But we are now speak-
ing of her physical appearance as
seen with a small telescope. It is
well known that the moon rotates
uniformly on her axis in the same
time that she revolves round the
earth. The consequence is that we
always see the same face, excepting
that, owing to the ellipticity of the
lunar orbit, and its being inclined
at an angle of about five degrees to
that of the earth, we from time to
time get a view of regions to a small
extent round each corner, so to
speak, or rather beyond each limb
(the technical word for edge of the
disc), as usually placed. The latter
appearances, known by the name
of libration, are of course only very
limited in amount. Roughly speak-
ing, our satellite shows us the same
face at all times, which is more and
more illuminated by the sun during
the progress of each lunation, until
at full moon he enlightens the
whole of the visible disc.
boundary of light and darkness is
called the terminator, which suc-
cessively advances over each region
during the waxing and retreats
again during the waning moon.
the former time it is sunrise at the
region covered by the terminator,
at the latter sunset. As the moun-

The

At

tains are thus seen in profile, casting long shadows behind them, these are the best times for observing regions on the moon's surface, many remarkable spots in which are indeed only visible on these occasions. We have not space to speak of these in detail; but in Mr. Webb's useful book, to which we have already referred, the intending observer will find a full account of them. The most remarkable of the lunar mountains and craters are the chain of Apennines, a little to the north of the moon's centre, the grand crater known as Copernicus, which lies on the terminator a day or two after the first quarter, a little northeast of the centre, and the 'metropolitan' crater, Tycho, with the curious system of rays or streaks surrounding it, which comes into view about the same time, but is near the south limb of the moon. The appearances of the large plains called Maria, from their having been formerly supposed to be seas, are likewise worthy of attentive observation. Mare Serenitatis, in the north-western quarter, contains some small craters, amongst which is one known as Linné, respecting which there has been much controversy during the last two years, it having been considered probable that great changes have taken place in it since it was first observed.

Occultations of stars by the moon are frequently very interesting phenomena. The suddenness of the star's disappearance when it takes place at the unenlightened edge of the disc is almost startling. To observe the reappearance it is necessary to know the part of the limb at which to look for it. These phenomena are not merely pleasing to see, but, when accurately observed with a good chronometer, are useful in science.

With regard to observation of planets, little can be said of the two inferior ones. Mercury is too close to the sun, and can only be seen when at or near the time of his greatest elongation. With a small telescope nothing can be done with him except, when the definition is good, to see that he has phases. Nor can much be done with Venus.

Her brightness at night is dazzling, and, exaggerating every imperfection of the telescope, makes it difficult to examine her steadily. It is probable that we never see her real surface, but only the clouded atmosphere. The best time to observe her is during the evening twilight. Diligent scrutiny has procured us lately some trustworthy knowledge of the surface of Mars. Small tele

scopes, however, cannot be expected to show much, and he will not for some years be in the most favourable position for observation. The phase is so slight as to be scarcely perceptible, the planet being always sensibly round. Brilliant white spots mark the poles, and it is generally allowed that these are due to large tracts of snow. The general colour of Mars is ruddy, probably owing to the nature of the soil. Unlike our earth, the land appears to occupy a larger proportion of the surface than the sea.

Jupiter is the planet which best repays the attention of the amateur. Even a small telescope, if its defining power is good, will exhibit his disc crossed by the belts (resembling in a small instrument fine black bars) in a direction parallel to his equator, and will also give the means of observing the four satellites. These may be seen at the times predicted in the 'Nautical Almanac to pass over the planet's disc (such passages are technically called their transits), to be occulted by it, reappearing on the other side, and to be eclipsed or to pass into and out of the planet's shadow. Accurate observations of the times of the latter phenomena (the eclipses) may be made with a good chronometer, and will be useful. The belts on the surface of the planet are produced by tracts of clear sky in the planet's atmosphere, their persistence being due to causes similar to those of the trade-winds on our earth.

Saturn being a smaller planet than Jupiter, as well as at a much greater distance, has not in itself so many points of interest. Those remarkable appendages, however, the rings, are at present well placed for observation, being well opened out

as seen from the earth. It is well known that they have several subdivisions, the interior ring being dusky and semi-transparent. But the possessor of a small telescope must be satisfied with a view of the ring as one object. The planet is attended by no less than eight satellites, but several of them require a powerful instrument to see them.

The two most distant planets, Uranus and Neptune, are too far off to show discs, especially Neptune, except when viewed with large telescopes.

To those more distant bodies which stud almost every part of the visible hemisphere, the words preeminently apply, 'The heavens declare the glory of God, and the firmament showeth His handy-work.' If the grandeur of the spectacle which the clear concave of a winter's night exhibits to the unaided eye calls forth in an irresistible manner such reflections as these, how can we express the intensity to which they are increased when even a moderately good telescope is applied to one of the richer parts of the blue infinite? None, indeed, but their Maker can tell the number of the stars, or call them all by their names.'

In this place we shall merely point out some of the more remarkable clusters and objects in some of the constellations, remarking that every increase in the power of the telescope employed will bring into view a larger number of objects worthy of attention.

That wonderful zone called the Galaxy, or Milky Way, has from the earliest ages attracted attention, and some of the ancients conjectured that its light was due to a vast assemblage of stars. Particular parts of it are distinguished by particularly great brightness, whilst other parts are darker, and in others gaps of total darkness are seen. Even moderate telescopes resolve the brightest parts of the zone into innumerable small, closely-crowded stars, and with good instruments it is seen that the different parts are richer in stars in perfection as their brightness to the naked eye is

greater, proving that the light of the galaxy is indeed due entirely to the multitude of distant stars. To give some idea of the scale of this multiplication, it may be mentioned that on one occasion Sir William Herschel estimated that not less than 116,000 stars must have passed through the field of his telescope in a single quarter of an hour. The course of the Milky Way amongst the constellations is principally, so far as visible to us, through Auriga, Cassiopeia, Cygnus, Aquila, and Sagittarius. In the latter, which is always low in the sky in these latitudes, is a part especially rich in stars. In Auriga the brightness is much less than elsewhere. In Cygnus there is a confused and irregular part, from which three partial streams diverge.

The Pleiades in Taurus are known to all. Viewed with the naked eye, most persons can only see six stars, but those possessed of acute sight see seven, and there is at least one authentic instance of as many as twelve having been so seen (by a lady). With a telescope, a group of fifty or sixty stars becomes visible, crowded together in a very moderate space. In the constellation Cancer, near the star e, and between y and 8, is a curious luminous spot called Prosepe, or the Beehive, which a very ordinary telescope shows to consist of a multitude of stars. Another telescopic cluster is situated in the sword-handle of Perseus, which may be considered as an offshoot of the Milky Way. It is nearly in a line between y Persei and & Cassiopeia.

Of the nebulæ it is scarcely desirable to speak here. Several of them are only immense clusters of stars, so distant as to require very powerful telescopes to resolve them, whilst others (especially the spiral nebulæ discovered by Lord Rosse) appear to possess a peculiar constitution of their own. markable one is the great nebula of Orion, over which many stars are scattered, but of which every increase in instrumental power shows fresh features. The sword of Orion consists of three stars, visible to the naked eye, called c, 0, and ; the

The most re

middle one, 'Orionis, marks the principal part of the nebula, which is, indeed, perceptible to the unaided sight. A moderately good telescopo shows four stars of unequal, but not greatly differing, magnitudes, in the form of a trapezium. The subject of double and multiple stars is, indeed, a most interesting part of astronomical research, many having been proved to have motions about each other of different periods. But the greatest part of the binary or physically double (as distinguished from merely optically double) stars are too close to be seen separate, except when high magnifying powers are applied to them. A few of the stars which may be seen double with comparatively small telescopes may be named here. They are, beginning with the closest pairs, Castor (magnitudes of components 3 and 34), y Arietis (4 and 5), Ursa Majoris (8 and 5), 61 Cygni (5 and 6), and 3 Serpentis (4 and 5).

It is obviously important for any one interested in astronomical observing to make himself familiar with the names of the constellations, and of the principal stars in each, so as to know them at sight. Mr. Proctor's Star Maps, adapted to the different constellation seasons of the year, are admirably suited for this purpose.

Good service may be done by amateurs who possess a knowledge of the stars in observing and recording the paths of remarkable meteors which they may happen to see. This has now become a branch of astronomy, and one of high interest. No telescope at all is required for its prosecution; but we are unwilling to close this article without reminding persons able to take part in these observations of the necessity of an accurate acquaintance with the stars, without which it is impossible to record the place of a meteor in such a manner that any use can be made of it. The times of appearance and disappearance, as well as the places where these are seen amongst the stars, should be noted if possible. The periods at which shooting-stars are most frequently seen are about April 20