488 



SCIENCE OF AGRICULTURE. 

 424 



Part II. 



'mufilL 



of smaller deviations from the flat surface. Inaccessible dimensions of height, as of trees 

 or buildings, are obtained by the quadrant, or by relative comparisons of shadows ; of 

 depth, as of water or wells, by rods ; of breadth or length, by finding the two angles of a 

 triangle whose base shall be in one extremity of the distance ; and apex in the other. 

 These, and many other equally simple problems in trigonometry, need not be enlarged 

 on, because they must be supposed to form a part of general education. 



3110. In portraying the general surface of land estates, different modes have been 

 adopted by modern land surveyors. The first we shall mention is the old mode of giving 

 what may be called the ground-lines only ; as of roads, fences, water. courses, situations 

 of buildings and trees, {fg. 425. ) This mode has no other pretensions than that of ac- 

 curacy of dimensions, and can give few ideas to a stranger who has not seen the property, 

 beside those of its contents and general outline. 



425 426 



3111. In the second, elevations of the o6;Vc^s are added to these lines ; but which, in 

 crowded parts, tend much to obscure them, {fig 426.) This mode is perhaps the best 

 calculated of any to give common observers a general notion of an estate ; more especially 

 if ably executed. Very frequently, however, this mode is attempted by artists ignorant 

 of the first principles of drawing, optics, or perspective, and without taste. 



427 





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