V. MAPS, ETC. 675 



it becomes possible to view any part of the map with pseudo-stereoscopic if 

 not with stereoscopic effect. Secondly, it is shown, that the insertion of 

 names improves the appearance of relief in models, and consequently in stereo- 

 scopic representations of them, while it spoils the effect of shading in ordinary 

 maps. 



32O2c. Perspective Map of Africa, according to French, 

 English, and German travellers. 



M. Launay, Professor at the Lyceum of Caen. 



This map was executed previously to the publication of the accounts of 

 Mr. Stanley, respecting Lake Ukerine, of Lieut. Cameron respecting Lake 

 Tanganiyka, and of M. Grandidier respecting Madagascar. 



3203. Map of Gaul, showing by different coloured tracings 

 the relative antiquity and importance of the Roman roads. 



M. Hayaux du Tilly, Paris. 



3203a. Old Spanish Map of the Province of Aragon, 



&c., with the roads, bridges, hill-shading, &c., inserted in MS. 

 by Captain H. Bristow, by means of the pocket-sextant, No. 3107a. 



H. W. Bristow, F.R.S. 



During the Peninsular War, great difficulty was experienced in getting 

 accurate maps of Spain for the British army. 



The most accurate Spanish maps then procurable were old, very defective, 

 and nearly useless as route maps, owing to the roads, hill-shading, &c. not 

 being shown upon them. These details had to be supplied for the use of the 

 army, by the officers attached to the Quartermaster-General's department, the 

 engraved maps serving as the groundwork for the new survey. 



The old Spanish map of the province of Aragon and surrounding districts is 

 one of those maps upon which the roads, bridges, the defences of Saragossa, 

 and other details, were so supplied in MS. by Captain Bristow, by means of the 

 pocket-sextant, No. 3107a. 



3204. Photographs from the original surveys, representing 

 the present mode of reproducing the ground by equi-distant 

 curves : 



1. Half a Norwegian square mile, on the scale of 1 '25000, used 



in lower tracts, well cultivated and more densely inhabited. 

 The curves representing a rise of 25 feet. 



2. A Norwegian square mile, on the scale of 1 * 50000, used in 



the higher and less inhabited parts of the land. The equi- 

 distant curves represent here a rise of 100 feet. 



Survey Office, Christiania, Norway. 



3204a. Specimen Sheets of the two most important 

 Productions of the Topographical Department at St. 

 Petersburg. Copper plate. 



The Topographical Department of the Imperial Russian 

 General Staff at St. Petersburg. 



1. Topographical map of the western part of European Eussia in 507 sheets. 

 Scale, 1:126,000. 



Uu 2 





