1831.] 
On Shading Mountain Land. 
215 
In some cases the problem is evidently impossible ; in others, no doubt, it is 
possible. Such of your readers, as have leisure, would confer a favour upon me by 
explaining the limits of these two cases, and also the solution ot the problem in 
the case of its possibility. 
IV. On Shading Mountain Land. 
1„ some of the former numbers of the Glean, nos, there have been articles 
upon the different methods of Shading Mountain Land: the method winch ob- 
tains at the Royal Military College at Sandhurst, has not been men mne . 
As the Royal Military College is the principal school tor topQg»F^ca p ar i- 
drawing and surveying, in the United Kingdom, and the place where the Officers 
intended for the topographical department of the British Stall are educated in 
their art, and consequently as the system held there, must be considered as 
fairly having a claim to the appellation of the English, it deserves a place 
among the several methods in use. It has not that ideal mathematical precision 
in the depths of shade, sought after by the Germans ; a precision which they 
propose to preserve even in the most hastily taken sketches in the field The 
inapplicability of this system to practice is self-evident ; for where can be the 
reason in weighing and measuring the ink, or the breadth of lines, to repre- 
sent, with mathematical accuracy, a declivity, whose degree o inc matio 
been guessed by the eye 1 ? In surveying, the degree of inclination o t egroun 
must be estimated by the eye, and practice will enable a man to do so v it i a 
considerable degree of correctness, as any person, who has had any experience, 
must be fully aware. Absolute perfection is not to be obtained without a la- 
bour in the measurements, and in the plan, far beyond what any survey can 
ever be worth ; but in fact, this rigid exactness and precision is not necessary 
for military purposes, to which class of topographical surveys I confine my 
remarks : an approximation suffices, but of course that approximation must 
swerve as little as possible, and in no notable degree to the eye, from the 
truth. The principles of the method taught at the two departments of the Royal 
Military College, reduced to the fewest possible words, are as follows:— 1st, a ver- 
tical illumination— 2d, the maximum degree of shade represents an inclination 
of about 45°, that is, the steepest declivities-3rd, perfect whiteness represents the 
horizontal plane. A deviation from the rule of vertical illumination is permit- 
ted in laying in the detail-trees, buildings, &c. in order to make the picture 
more pleasing to the eye, and to give the objects relief. Shading by t le pen 
alone, without the aid of the brush, in hatches, is executed at Sandhurs 
style unequalled in any part of the world. The younger Stevens, who died there 
about two years ago, most ingeniously introduced a ciossin D of the u 
superbly represented the gradual swellings and rollings of the surface, w ^ 
delicacy and accuracy of the most cleverly handled brush ; since is ta , 
°"'ing to the time this very high finish consumed, and the opinions repea e y 
given in the Board Room, that a less laborious method wou answu, 
crossing has been laid aside. The beautiful appearance of these p ans, in w i 
tbe evident consumption of time, and the immense labour weie s 
1 The advantage of the German method is that it is capable of 
any degree of accuracy obtainable— guesses by guesses measuremen ) 
meat.— .E d. 
