Chap. 3.] by cylindrical and conical Mirrors. 109 



as there do not proceed from each point fimple rays 

 of light, but pencils of rays, they are modified in this 

 mirror upon the fame principles as in the convex 

 mirror, and confequently the image will appear fmaller 

 than the object, and nearer to the eye than in the plane 

 mirror. 



Hence it will be evident, that we may fee in the 

 center the image of whatever is painted on the exte- 

 rior circumference A H D, and the extremities of the 

 image will be formed from the interior circle C G F ;; 

 and as the curvature or convexity of the mirror is 

 greater towards the apex or point of the cone, it follows, 

 that that which is the moft extended in the object will 

 be the moft compreffed or concentrated in the image. 

 Thus the dark part of the board (Plate VIII. fig. i.) 

 is intended to reprefent in the mirror an ace of fpades ; 

 and the points a, b y , d, <?,/, g, fcc. which are neareft to 

 the mirror, form the outer circumference of the image, 

 and the points i, 2, 3, 4, 5, 6, 7, 8 of the external cir- 

 cumference of the board unite in the cerrter of the 

 image almoft at an imperceptible point. 



