292 A New Kind of Miniature. 



A NEW KIND OF MINIATURE. 



A veet ingenious and beautiful application of optical principles 

 to the mounting of photographic miniatures has been recently 

 made by Mr. Henry Swan, of the ' c Casket Portrait Company," 

 Charing Cross. The effect of the new process is to exhibit the 

 subject of the portraiture with life-like verisimilitude, and in 

 natural relief. You take up a small case, and look through 

 what appears to be a little window, and there stands or sits be- 

 fore you, in a pleasantly-lighted chamber, a marvellous effigy of 

 a lady or gentleman, as the case may be. The projection of the 

 nose, the moulding of the lips, and all the gradations of con- 

 tour, are as distinct as if an able sculptor had exercised his 

 skill ; but the hair and the flesh are of their proper tint, and 

 the whole thing has a singularly vital and comfortable look. 

 Indeed, were it not for the reduction in size, it would be difficult 

 to avoid the belief that an actual man or woman, in ordinary 

 dress, and with characteristic expression, was presented to your 

 eye. We might, indeed, compare these admirable pictures to 

 accurate reflections of the persons themselves in a diminishing' 

 glass, and no one can see them without being struck with their 

 marked superiority over ordinary portraits. 



In order to produce these beautiful and unexpected effects, 

 two portraits, taken at a suitable angle, are arranged upon two 

 prisms, placed almost in contact so as to form a quadrangular 

 block. Each prism is ground to an angle of 39° or 40° ; one 

 picture is placed at the back of the combination and another at 

 the side of the prism nearest the eye. When we try to look 

 through the combination, the two images are combined in one 

 stereoscopic picture, and the action is, thus explained in a paper 

 read by Mr. Swan before the British Association, at their New- 

 castle meeting, where the portraits were much admired : — " The 

 reason of this curious phenomenon is, that all the rays which 

 fall on one side of a line perpendicular to the surface of the 

 prism next the eye suffer total reflection at the oblique inner 

 surface of that prism, while the rays which fall on the other 

 side are transmitted unaltered through the body of the com- 

 bination. Thus it is that one of the eyes only perceives the 

 object at the back of the prisms, while to the other the picture 

 at the side is alone visible, that, apparently, being at the back 

 also. It necessarily follows that if the pictures have been taken 

 in accordance with the principles of binocular vision, the result- 

 ing image seen in the interior of the crystal Vill bo quite solid, 

 every detail being wrought in perfect relief with the most 

 exquisite delicacy. To the scientific observer it will bo evident 

 that, to produce the effect intended, care must be taken not 



