354 The Realm of Nature 



scale before the elevation became 500 feet lower, but along AC this 

 difference of height is reached in three divisions of the scale, or the 

 slope is three times as steep and the contour-lines are much closer. 

 The student, if residing in the United Kingdom, should procure and 

 carefully study the Ordnance Survey maps (contoured) on the one- 

 inch and six-inch scales for his own locality. He might advan- 

 tageously follow the lines in pencil to make them more prominent, 

 and then paint the map in successive washes, deepening the colour 

 within the higher contour-lines as in Plates XI. and XVI. He will 

 thus produce a pictorial relief map, on which all the features of hill 

 and dale will stand out with great distinctness. The Ordnance maps 

 for England and Wales are to be had from Mr. Edward Stanford, 

 55 Charing Cross, London, S.W. ; those for Scotland from Messrs. 

 John Menzies and Co., 12 Hanover Street, Edinburgh; and those 

 for Ireland from Messrs. Hodges, Figgis, and Co., 104 Grafton Street, 

 Dublin. Mountains and watersheds are frequently represented on 

 maps by shading in certain conventional ways, so as to bring out the 

 general appearance of the surface. One of these systems combined 

 with contour-lines is shown in the map of a glacier in Fig. 54. 



