the modern maker uses for a 6-inch telescope a stand much more solid and steady than was deemed sufficient eighty years ago for an instrument of 9-6/10 inches. Attention is particularly directed to the way in which nowadays all the motions are brought to the eye-end so as to be most convenient for the observer, and frequently, as in this case, accomplished by electric power, while the declination circle is read by means of a small telescope so that the large instrument can be directed upon any object with the minimum of trouble. The driving clock, well shown on the right of the supporting pillar, is automatically controlled by electric current from the sidereal clock of the observatory. [Illustration: PLATE II. 6-inch Photo-Visual Refractor, equatorially mounted. Messrs. T. Cooke & Sons.] We have now to consider the reflecting form of telescope, which, especially in this country, has deservedly gained much favour, and has come to be regarded as in some sense the amateur's particular tool. [Illustration: FIG. 12.--8-INCH REFRACTOR ON EQUATORIAL MOUNTING.] As a matter of policy, one can scarcely advise the beginner to make his first essay with a reflector. Its adjustments, though simple enough, are apt to be troublesome at the time when everything has to be learned by experience; and its silver films, though much more durable than is commonly supposed, are easily destroyed by careless or unskilful handling, and require more careful nursing than the objective of a refractor. But, having once paid his first fees to experience, the observer, if he feel so inclined, may venture upon a reflector, which has probably more than sufficient advantages to make up for its weaker points. First and foremost of these advantages stands the not inconsiderable one of cheapness. A 10-1/2-inch reflector may be purchased new for rather less than the sum which will buy a 4-inch refractor. True, the reflector has not the same command of light inch for inch as the refractor, but a reflector of 10-1/2 inches should at least be the match of an 8-inch refractor in this respect, and will be immeasurably more powerful than the 4-inch refractor, which comes nearest to it in price. Second stands the ease and comfort so conspicuous in observing with a Newtonian. Instead of having almost to break his neck craning under the eye-piece of a telescope pointed to near the zenith, the observer with a Newtonian looks always straight in front of him, as the eye-piece of a reflector mounted as an altazimuth is always horizontal, and when the instrument is mounted equatorially, the tube, or its eye-end, is made to rotate so that the line of vision may be kept horizontal. Third is the absence of colour. Colour is not conspicuous in a small refractor, unless the objective be of very bad quality; but as the aperture increases it is apt to become somewhat painfully apparent. The reflector, on the other hand, is truly achromatic, and may be relied