The cheapest plan of copying manuscript books is to use one of the ordinary methods of copying written matter. This, however, necessitates the first copy being written out with special ink. If the writing is on one side of the paper only, procure some fairly pure paper and mix together (A) potassium ferricyanide 21 oz., water 10 oz.; and (B) ferri-aminonium citrate 21 oz., water 10 oz. Mix an equal quantity of each, and coat the paper by rubbing the solution well over it several times with a soft sponge or tut't of cotton wool. The paper should be coated as evenly as possible, but no notice need betaken of streakiness, so long as the paper has been well covered. A convenient tool consists of a glass tube through which slides a loop of fine wire holding a tuft of wool. When pulled up tight, the wire is wound around the top of the tube. As the potassium ferricyanide is exceedingly poisonous, it is not advisable to get more on the fingers than can be avoided. The paper is printed in contact with the drawing or writing in the usual pressure frame, or the sheets may be fastened together with wooden clips between two pieces of glass.

Printing on this paper requires a longer time (six to ten times) than silver paper; but on taking the print from the frame it merely requires washing in water, to the first bath of which it is advisable to add a little citric acid. This process gives white letters on a blue ground. For black lines on a white ground the following is recommended. Make up three stock solutions: (A) Gum 1 part, water 5 parts. (B) Ferri-ammonium citrate 1 part, water two parts. (0) Ferric chloride 1 part, water 2 parts. For use, take (A) 30 parts, (B) 8 parts, (C) 5 parts. Develop with potassium ferrocyanide (or yellow prussiate) 50 gr., water loz., and fix in a 10-per-cent. solution of hydrochloric acid. If the writing is upon both sides of the paper, the only plan will be copying through the camera. The book must be taken to pieces, and pages in consecutive order arranged on a board to go as near as possible into the size plate to be used, and copied on process plates, using hydroquinone developer. From these negatives enlargements could be made, or the optical lantern could be used. Great care must be taken to get a thoroughly sharp negative: use a lens with a flat field or a small stop and keep the negatives fairly thin.

If, for example, the pages are 6 in. by 4in., then twenty-four of these could be copied in one exposure on a half plate, making seventy-five exposures in all. The wet collodion would be the best and cheapest process to employ.