1878.] to the Rep rod act i 071 of Maps and Flans. 55 



For some time, however, the use of photography in the Ordnance 

 Survey Office appears to have been limited to obtaining accurate reduced 

 prints for the engravers to trace from on to their copper-plates, and was 

 not extended to producing maps for publication, owing to the expense 

 and comparative slowness of production of photographic silver prints, com- 

 pared with the lithographic or copper-plate impressions, to say nothing of 

 their want of permanence. 



Experiments were next made with some of the so-called carbon pro- 

 cesses, then recently discovered in France b}'- Poitevin and first worked 

 in England by Pouncy, with the object of transferring the photographic 

 design at once on to the copper-plate, instead of tracing from the photo- 

 graphs by hand. The results obtained were not very satisfactory and a 

 trial was made of Mr. Asser's photolithographic process, which had been 

 published shortly before. Although this process was not found quite 

 adapted to the purpose intended, the advantages of a method whereby 

 facsimile prints in lithographic ink might be obtained and transferred 

 to zinc or stone, so as to permit of a large number of copies to be 

 printed off as easily as from an ordinarj^ lithographic transfer drawing, and 

 with precisely the same advantages in respect to cheapness and permanence, 

 were obvious ; and in 1860, after several trials, Captain A. de Courcy Scott, 

 R. E., who was in charge of the photographic operations at Southampton, 

 perfected the process of photozincography, which has since been employed 

 with so much success and advantage at the Ordnance Survey Office, 

 Southampton, and in this country at the Survey Offices in Calcutta, Dehra 

 Dun, Puna and Madras, as well as at other public and private institutions 

 in other parts of the world. 



By a curious coincidence, at the very time when this process was being 

 worked out in England, Mr. W. Osborne, of Melbourne, Australia, indepen- 

 dently perfected an almost identically similar process of photolithography, 

 which has been extensively used in the Crown Lands Offices of Victoria and 

 Adelaide for reproducing the maps of the Australian Surveys, and has also 

 been worked commercially by Mr. Osborne in Europe and America. 



These two processes, appear to have been the first instances of the 

 practical application of photography to the reproduction and multiplication 

 of maps for publication. They still remain, however, very extensively used, 

 and are by the simplicity, cheapness and rapidity of their operations and the 

 facilities they offer for the reproduction of maps of large size, of greater 

 practical value than other processes which have since been brought forward 

 with the same object, and are perhaps capable of producing finer results 

 within the limits of a single negative. 



In India, the ever-increasing wants in the way of communications by 

 rail, road and river, and the rapid extension of irrigation and other 



