The Daguerreotype and its AppUcatiotcs. 143 



In Daguerreotype miniatures, moles, freckles and even hairs are 

 copied with microscopic accuracy. The iris of a dark eye is 

 sharp and distinct, and the white dot of light upon it, is given 

 with surprising beauty. If the iris is of a light blue, it is hable 

 to solarize, before the face and dress make any decided impression 

 on the iodized surface. This minute accuracy is preserved in 

 the very small miniatures, intended to be worn as ornaments. 

 The general sharpness of the portrait is probably increased by a 

 diminution of its size, and with the aid of a lens all the "individ- 

 ual peculiarities" may be discovered. By enlarging the dimen- 

 sions of the portrait, this character is impaired, and entirely dis- 

 appears when the face becomes two inches in length. See Amer- 

 ican Repertory for October, p. 209 — Professor Draper's paper on 

 this subject. 



Mr. Wolcott's external arrangements are similar to those already 

 described. If the sun's light is employed, the ray is directed by 

 a looking glass^to the sitter, whose eyes are defended by an inter- 

 posed blue glass. 



An elliptical metallic mirror seven inches in diameter, and of 

 twelve inches focal length, is secured at the back of a box open at 

 one end. Within this box, and near its open end, is placed the 

 movable frame which supports the plate. In operating with this 

 apparatus, the sitter should be about eight feet distant from the 

 open end of the box ; the plate with its iodized surface facing the 

 mirror is then placed in the frame previously adjusted to the focus. 



The time required for the camera operation varies from ^m. to 

 _2m., if the sun's light and the mirror are employed ; 3m. are ne- 

 cessary to its completion in diffused light. 



In this apparatus the position of the plate between the sitter 

 and the metallic mirror, limits its size. Originally this limit was 

 two inches square ; improvements however, have been made by 

 Mr. Wolcott, which enable him to use them of larger dimensions. 



This apparatus possesses some decided advantages over that fit- 

 ted with lenses. Portraits can be taken when the sun is obscur- 

 ed by clouds, and the picture is not reversed ; that is, the right 

 and the left hand do not change places. 



Mr. Ibbotson, of London, has. succeeded in copying magnified 

 images by artificial light. That from lime rendered incandescent 

 by the flame of the oxyhydrogen blowpipe, is said to be suffi- 

 ciently intense for this purpose, and produces the result in a 

 shorter period than solar light. 



