PART VII. 



PICTURESQUE 



IMPROVEMENT. 



395 



which are properly cascades. Both kinds may be imitated in 

 improved scenery, though hitherto this has seldom been well 

 done, owing either to the limited practical knowledge of per- 

 sons of taste — or the limited or vitiated taste or want of judg- 

 ment in those who have had the requisite practical knowledge. 



1. Waterfalls may either be imitated directly, by being copied 

 from nature; or indirectly, by the introduction of weirs for the 

 use of water-mills, as mentioned toward the end of the last 

 sub-section. In imitating nature, the strength and durability 

 of the whole must be taken into consideration, no less than its 

 beauty. Strength depends upon the general form of the ag- 

 gregate of materials, which ought to be nearly that of Plate 

 XVII. fig. 2. a a a. Durability depends chiefly upon the foun- 

 dation ; which ought in every case, upon a great scale, to be 

 the natural rock; and upon a small scale, the most secure 

 causeway, fixed by oak piles and cross planks; — it depends 

 also upon the quality of the masonry, which ought to be ex- 

 ecuted with accuracy and care *. 



* No kind of mortar should be used, but what is capable of resisting water. The 

 best for this purpose is common lime-stone used immediately after being burned ; 

 which, as Dr. Anderson has shewn, will harden instantly, and remain so as well, 

 or better, under water than in any other situation ; but where unburnt lime cannot 

 conveniently be had, or where, from deficiency of good workmen, or other circum- 

 stances, it could not be well burned, melted, and poured into the walls on the spot, 

 — there are other compositions which, though much more expensive, may be used 

 in its stead. See embanking. 



