204 



SCIENCE OF THE STUDY OF TREES. 



PART If. 



gram, as is clone in fig. 2. The parallelogram suited lor an octavo page is 

 4 in. broad, and 7a in. long ; and the divisions are a fourth of an inch each. 

 This parallelograrn admits of a drawing of a tree 30 ft. high, with its branches 

 extending over a space 16 ft. in diameter. These dimensions maybe con- 

 sidered as the maximum for trees ten years planted, even under the most 

 favourable circumstances; and, therefore, this size of page, and this scale, are 

 what we have adopted for our Arhoretum Britannicum. One page being 

 marked as in j%. 2., all the other pages in the book, or any number of separate 

 pages, may be marked in a similar manner by pricking through them from the 

 different divisions of the scale. 



For the purpose of drawing full-grown trees within the limits of the same 

 sized parallelogram, we assume 90 ft. as the maximum height of the tree, 

 and 48 ft. as the maximum diameter of the space covered by the branches ; 

 and, for this purpose, the same division of the inch into four parts will 

 suffice, but with this difference, that each of these parts must now be con- 

 sidered as .3 ft., instead as of 1 ft. Fig. 2. is marked in this manner, in 

 the inside of the parallelogram, for old trees ; and it is marked in the man- 

 ner before described, on the outside of the parallelogram, for young trees. 

 In practice, it is unnecessary to mark the figures, as the draughtsman will 

 easily bear in recollection what each division represents. For trees exceeding 

 90 ft. in height, and 48 ft. in width, the margin may be encroached on, to the 

 extent of half an inch on each side, and at top and bottom, which will affortl 

 space for a tree 102 ft. high, and with a head 60 ft. in diameter. 



The draughtsman may now be considered as haying got his directions, as 

 far as respects paper and scale. Having prepared his pages, he will next pro- 

 cure two black-lead pencils, one hard, and the other hard and black (tech- 

 nically n and h b), together with a foot rule and a chair. The next thing to be 

 done is, to choose the tree and the aspect from which it is to be drawn. In 

 making a choice, the average form, height, and character of the species ought 

 to be "taken, as far as practicable ; and not a specimen remarkable either for 

 its height, or for its singularity or peculiarity ; aud^ the point from which it is 

 to be drawn ought, if possible, to be on the south, south-east, or south-west 

 side of it. The rule is, that the sun ought always to be behind the draughts- 

 man, and rather to the left than to the right of him. All other circumstances 

 being the same, therefore, when a tree is to be drawn in the morning, the 

 draughtsman ought to place himself on the south-east side of it, at mid-day on 

 the south side, and in the afternoon on the south-west side. The next point 

 is, the distance from the tree at which the spectator ought to place himself. If 

 he sits, which is, in general, the best mode, though some artists prefer a stand- 

 ing posture when drawing, twice the height of the tree will be a very good 

 distance ; but if he stands, and the tree has a very short trunk, say one under 

 6 ft. in height, it will be advisable for the artist to add to his distance from the 

 tree once, twice, or thrice his own height ; otherwise the height of his eye 

 above the lowest branches of the tree might cause the branches to conceal 

 more of the trunk than would be desirable. It may be useful to add, that the 

 principle on which the distance is chosen is that of being able to see the tree 

 as a whole, or as an entire mass of light and shade easily comprehended by 

 the eye fixed in one position, as opposed to that of seeing it in detail, and by 

 changing the position of the eye. Experience has shown that the eye cannot 

 comprehend more with ease than the fourth part of a circle, v/hether we take 

 this circle as a vertical or as a horizontal plane, or as a solid globe, and imagine 

 the eye in its centre. The principle which directs the position of the sun to 

 be behind the spectator rather than in front of him, and at his left band rather 

 than at his right, is, that a portion of the tree may be in light, and another 

 portion in shade, in order to show its general form and rotundity, and that the 

 portion in shade may always be, for i-easons to be hereafter given,^ on the 

 right hand. In many cases it may be necessary to draw the tree from the 

 north side, and, in others, to draw it when the sun does not shine : in both 



