652 



PRACTICE OF AGRICULTURE. 



Part III. 



rent, and directed it into its wonted channel. And in almost any case, by judiciously 

 placing, in a similar manner, a pier or other obstruction proportioned to the magnitude 

 of the power to be counteracted, the like effect may be produced. 



4039. In the use of jnei-s great caution is requisite, for a very little reflection will 

 show, that they are more likely to increase than to remedy the evil they are intended to 

 cure. We have seen the injurious effects of such piers on the Tay and the Dee ; and on 

 a part of the Jed near Crailing they are so numerous, that the stream is, to use a familiar 

 phrase, banded about like a foot-ball, from one shore to the other ; behind every pier an 

 eddy is formed, and if the stream does not strike the pier exactly, a breach in the bank takes 

 place. Many of these piers have, in consequence, been taken down. The use of such piers 

 can only be justified where the obstruction, from ill-neighborhood or some such cause, 

 cannot be removed from the opposite bank ; or where, as is sometimes the case, it arises 

 from an island of sand or gravel thrown out by the river near its middle, and which, 

 however absurd it may appear, the interested parties cannot agree as to who may remove 

 it. The case of buildings also being in danger, may justify such a pier for immediate 

 protection ; but if such breaches are taken in time, a few loads of loose stones dropped 

 in the breach, as recommended by Smeaton, will effect a remedy without the risk of 

 incurring or occasioning a greater evil. 



4040. In the construction of piers, attention is required to secure the foundation, either 

 by first throwing in a quantity of loose stones, which the water will in a great measure dis- 

 pose of so as to form {i flat surface ; or by the use of piles either under, or in single or 

 double rows around those parts of its base in contact with the river. {,fig' 520 a.) The 

 elevation (6), where it is not required to act with great violence on the opposite shore, 

 ought to be bevelled back on all sides exposed to the water, towards the middle of the 

 structure (c). In the most important cases stones are the only fit materials, and these 



should be regularly jointed and laid in cement according to the best practice of masonry. 

 But, in general, a case of wicker work, of the proper shape, may be filled in with loose 

 stones, some earth, together with the roots of such plants as tussilago petasites, elymus 

 arenarius, gallium^ &c. These will form a barrier of considerable durability for some 

 years, and probably till the evil is so far subdued that, when the wicker case decays, its 

 contents will have sufficiently consolidated to effect the object without further care. If 

 not, the wicker case may be renewed. In ordinary cases, a mere wicker hedge project- 

 ing into the water will effect the object without further trouble. 



4041. The sheath, or land-guard of loose stones, which Marshal recommends, and 

 which, in eflfect, is the mode already mentioned (4037.) as preferred by Smeaton, is ap- 

 plicable to the following cases : First, where the river is confined in the part where it is 

 required to be bent, by rocks or otherwise, to ah unaltered channel ; as it frequently is, 

 in subalpine situations ; and, secondly, where a deep pool occurs, in that part, in low 

 water, so as to render it difficult to get a proper foundation for a pier. Where the 

 foot of the injured bank is covered with a pool at low water, shelve off the brink of 

 the bank, and shoot down loose stones from the top of it ; suffering them to form their 

 own slope, in the action of failing, and by the operation of succeeding floods; continuing 



