denorninated the Aerial Reflector . 43 



cess in tliis 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 fix- 

 ed, 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 opposite to the 

 speculum, and connected with an apparatus, by which it]could oc- 

 casionally be moved either in a vertical or a horizontal direction. 

 With the instrument fitted up in this manner, I obtained 

 some very pleasant and interesting viev^^s of the moon, and of 

 terrestrial objects. But finding that one side of the tube inter- 

 cepted a considerable portion of light from the object, I deter- 

 mined to throw aside the tube altogether, and to fit up the in- 

 strument on a different plan. A short mahogany tube, about 

 three 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 ex- 

 tremity 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. 



Plate I. Fig. 1. Exhibits a general representation of the in- 

 strument in profile. AB is the short tube which holds the spe- 

 culum ; 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 a h, 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 /, this tube 



