HEADQUARTERS OF SURVEY DEPARTMENT. 227 



kinds, and of electrotyping for the duplication and correction of 

 hand-engraved maps. 



The first experiments in heliogravure were made, with fair success, 

 about 1877 with a photo-electrotype process based on Geymet's, 

 which was originally brought out by Mr. J. W. Swan, the inventor 

 of the carbon process. In the following year Captain "Waterhouse, 

 while in Europe on privilege leave, visited the Military Geographical 

 Institute at Vienna, at that time the only large geographical office 

 working the process, and obtained a good deal of valuable informa- 

 tion regarding it ; but little progress was made till 1882, when he 

 introduced a new process for producing " grain " on the plates of 

 half-tone subjects which he had worked out, with the aid of the 

 Autotype Company, while on furlough in 1880-81. In this process 

 the wet-gelatine relief is dusted over with sand or some similar 

 granular material, previously 'waterproofed by treatment with a greasy 

 substance like wax, so that it might easily be removed from the 

 gelatine relief when dry. The effect of the sand was to roughen 

 the gelatine surface proportionately to the depth of gelatine and so 

 produce a graduated grain stronger in the shadows than in the 

 lights. The gelatine surface was then blackleaded and electrotyped. 

 In this way an engraved mezzotint plate was produced from which 

 very perfect half-tone prints could be printed. This process proved 

 very valuable for the production of some 3,000 copies of the " Award 

 Certificate" of the Calcutta Exhibition in 1883-84, and several 

 plates of illustrations of Indian art-ware in the Exhibition as well 

 as of brush shaded maps and drawings were reproduced by it, but 

 owing to climatic causes it was always rather a difficult process to 

 work, and the plates required a good deal of touching up. 



In 1884, with the assistance of a skilful carbon printer, Mr. A. W. 

 Turner, experiments were made with the photo-etching process, 

 which was on the same principle as the photoglyphic process 

 originally invented by Fox Talbot, and which had recently been 

 re-introduced with modifications by Herr Klic of Vienna. 



The process was worked out successfully on the bare information 

 obtainable from the photographic journals, but further improve- 

 ments, learnt at the Military Geographical Institute in Vienna, 

 during Colonel Waterhouse's furlough in 1886, were introduced in 

 1887, and since that time the process has been working on a 

 perfectly practical footing and is found very valuable for all kinds 

 of delicate work in line or half-tone. It has the great advantage 

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