NATUKAL PHILOSOPHY. 207 



picture separates from the glass to the paper. It can be transferred in the 

 same manner on cloth. The surface of the picture is now gently touched up 

 with fine varnish on a pellet of cotton wool, care being exercised not to 

 injure the delicate surface. This varnish makes the surface slightly sticky to 

 receive any of the dry colors for tints. When these are laid on, the transfer- 

 red picture is complete. 



Gutta Percha Photograph. The following is a description of a new process 

 recently patented by Mr. F. S. Archer, of London : The negative picture is 

 produced hi the ordinary manner upon the collodion film on a sheet of glass, 

 and it is fixed and dried in the ordinary manner ; it is then dipped into a solu- 

 tion of gutta percha, and after draining off the excess it is dried by a gentle 

 heat, and a nearly transparent film of gutta percha will be found upon the 

 collodion. If the film is not sufficiently thick this operation is repeated one 

 or more tunes until a sufficiently thick film of gutta percha is formed. The 

 whole is next immersed in water, which causes the collodion to separate from 

 the glass and come away with the film or sheet of gutta percha firmly adher- 

 ing to it. These films or sheets are sufficiently transparent, and are tough 

 and flexible, and may be handled without injury, when they may be pre- 

 served in a book or portfolio. The inventor employs these films for producing 

 the positives in the same manner that the ordinary glass negatives are 

 employed. They may be placed with either side in contact with the paper, 

 according as it is wished to obtain a correct or a reversed picture. In pro- 

 ducing the negative picture in the camera, the sheet of glass may be placed 

 either with the collodion surface towards the object, or with the plain surface 

 towards the object. In lieu of glass a smooth sheet of silver, or other metal or 

 material which is not injuriously acted upon by the chemical agents employed, 

 may be used. The solution of gutta percha should be made with a solvent 

 like benzole, which evaporates with rapidity. The plate may be coated or 

 covered with a film of gutta percha before applying the collodion, which is 

 afterwards poured upon it in the ordinary manner. The picture is then to be 

 produced and fixed, and washed and coated with the gutta percha, and 

 removed from the plate, as described thus a collodion film coated on both 

 sides with gutta percha will be obtained. If the glass plate be covered with a 

 stout film of gutta percha before pouring the collodion upon it, as above men- 

 tioned, the picture may afterwards be simply varnished with any suitable varnish 

 instead of the gutta percha solution, and then removed from the plate mentioned. 



MayalVs Photographic Ivory. E. Mayall, of London, has obtained a patent 

 for the application and use of a new material in photography, known by the 

 name of " artificial ivory." This substance is formed of small tablets of gela- 

 tine or glue immersed hi a bath of sulphate of alumina (alum) or the acetate 

 of alumina. A combination takes place between the alumina and glue, and 

 forms the substance for receiving the photographic pictures, as a substitute for 

 the common metal plates and prepared paper. It is stated that it receives a 

 polish equal to ivory, and the tints of the pictures have an exquisite softness, 

 far surpassing those of the daguerreotype. The process for obtaining pictures 

 is the same as that commonly pursued in photography. 



The Oxymel Process in Photography. This is the name given to a new pro- 



