The Kallitype process of printing is the subject of a patent. It con-sists of first coating any fairly pure piper with a mixture of silver nitrate and ferric oxalate. The ferric oxalate is reduced to the ferrous state by the action of light, and thereby reduces the silver in contact with it, thus forming a visible image, which is simultaneously developed and toned, and afterwards fixed. Dissolve 70gr. of ferric oxalate in l oz. of distilled water, and add 15 gr. of silver nitrate. Brush this solution with a sponge or tuft of cotton wool well and evenly over the surface of the paper, and allow to dry-, then place the paper in contact with a bright negative in the printing frame, and expose fully to a good light. Immerse for from fifteen minutes to half an hour in a solution containing 2 5gr. of Rochelle salt and 25 gr. of borax to l oz. of water. This gives a black image. By decreasing the borax to 9gr. and adding three drops of hydrochloric acid, a sepia picture is obtained. Transfer for ten minutes to a 1-per cent, solution of ammonia, then wash for half an hour, and the print is finished. Ferric oxalate may be made as follows: Add to 2oz. of ammonia iron alum, in a 20 oz. measure, loz. of strongest liquor ammonia with 1 oz. of distilled water.

Stir well and allow the precipitate to fall. Wash by decantation till alkalinity disappears; then add 1 oz. of crystallised oxalic acid, and make up to the desired strength with distilled water. Ferric oxalate purchased of a chemist should be tested by adding to a solution of it a few drops of a solution of potassium ferricyanide, when, if it has changed to the ferrous state, it will throw down a dense precipitate of Prussian blue.