About the year 1822, an old speculum 27 inches in focal length, very imperfectly polished happened accidentally to come into my possession; and feeling no inclination to fit it up in the Gregorian form, I formed the resolution of throwing aside the small speculum, and attempting the _front view_ notwithstanding the uniform assertion of opticians, that such an attempt in instruments of a small size is impracticable. I had some ground for expecting success in this attempt, from several experiments I had previously made, particularly from some modifications I had made in the construction of astronomical eye-pieces, which have a tendency to correct the aberration of the rays of light, when they proceed somewhat obliquely from a lens or speculum. In the first instance, I placed the speculum at the one end of a tube of the form of a segment of a cone--the end next the eye being somewhat wider than that at which the speculum was fixed, and its length about an inch shorter than the focal distance of the mirror. A small tube for receiving the different eye-pieces was fixed in the inside of the large tube at the end next the eye, and connected with an apparatus by which it could occasionally be moved either in a vertical or horizontal direction. With the instrument fitted up in this manner, I obtained some interesting views of the moon, and of terrestrial objects. But finding that one side of the tube intercepted a considerable portion of light from the object, I determined to throw aside the tube altogether, and to fit up the instrument on a different plan. A short mahogany tube, about 3 inches long, was prepared, to serve as a socket for holding the speculum. To the side of this tube an arm was attached, about the length of the focal distance of the mirror, at the extremity of which a brass tube for receiving the eye-pieces, was fixed, connected with screws and sockets, by which it might be raised or depressed, and turned to the right hand or to the left, and with adjusting apparatus by which it might be brought nearer to or farther from the speculum. Fig. 69 exhibits a general representation of the instrument in profile. AB is the short tube which holds the speculum; CD the arm which carries the eye-tubes, which consists of two distinct pieces of mahogany; the part D being capable of sliding along the under side of C, through the brass sockets EF. To the under part of the socket F is attached a brass nut with a female screw, in which the male screw _ab_ acts by applying the hand to the knob _c_, which serves for adjusting the instrument to distinct vision. G is the brass tube which receives the eye-pieces. It is supported by a strong brass wire _de_, which passes through a nut connected with another strong wire, which passes through the arm D. By means of the nut _f_ this tube may be elevated or depressed, and firmly fixed in its proper position; and by the nut _d_ it may be brought nearer to or further from, the arm D.