1878.] to the Reproduction of Maps and Plans. 123 



on a paper specially prepared for photoeoUotype printing, which would only 

 have to be sensitised when required and, after exposure under the negative, 

 could be fastened down on to a metal plate and printed in an ordinary print- 

 ing press. In this way also views or other subjects unfit for photozinco- 

 graphy might be printed if required in larger numbers than could con- 

 veniently be accomplished by silver-printing. 



In connexion with such a method of printing by photoeoUotype, it 

 would be very convenient to arrange for drawings being made on a tissue 

 consisting of a transparent basis, such as waxed paper or sheet gelatine, 

 covered with a thin opaque film which could be easily cut through with an 

 etching -point. Such drawings would form very perfect reversed negatives. 



Aj^paratus and appliances for taking views by the dry and wet pro- 

 cesses and for taking prints of them in the ordinary way should also form 

 part of the equipment. 



A military photographic travelling field equipment of this kind has 

 been organised in the English service and attached to the Field Train of 

 the Royal Engineers. A description of it was given by Capt. Abney in 

 a paper read before the British Association in 1874.* 



In the case of operations in a wild or hilly country, the photographic 

 equipment must be limited to the most indispensable requirements, and be 

 regulated by the nature of the transport available and by other local and 

 military considerations. It is very doubtful whether photozincography could 

 be advantageously carried out in such localities, and the photographic outfit 

 might be limited to some moderate-sized sets of apparatus for views and 

 copying, with a large stock of dry plates and the necessary appliances for 

 silver-printing. Some of the simple iron processes of printing might 

 perhaps be usefully employed. Recent improvements in the preparation of 

 dry plates by what are called the emulsion processes have greatly facilitated 

 and simplified the practice of photography in the field, so far as taking the 

 negatives is concerned, and a sensitive tissue has been prepared by Mr. 

 Warnerke for this purpose, by which the use of glass plates may be 

 dispensed with. 



The apparatus, &c., should be strongly packed in moderate -sized 

 parcels so as to be carried either by men or pack-animals. 



At the same time it should be stated that it seems very doubtful 

 whether photography can really be employed with much advantage in the 

 field under the conditions of modern warfare in civilised countries. Its 

 main use in any case will be the copying of reconnaissances and sketches 

 of positions preparatory to a battle and of sketches and views of positions 

 on the battle-field after the event. The delicate operations required either 

 for taking negatives or for printing copies from them cannot satisfactorily 

 * '■British Journal of Thoiography,' Vol. XXI, p. 415. 



