30S 



SCIENCE OF GARDENING. 



Paut II. 



and other fruit-trees for public sale. It seems to be the most economical wall that can 

 be devised, as the parts forming piers are as useful as any other parts of the wall, which is 

 not the case with piered walls of the common sort. 



245 



1 572. The piered wall (Jig. 246. ) may be of any thickness with piers generally of double 

 that thickness, placed at regular distances, and seldom exceeding the wall in height, unless 

 for ornament. These piers are generally made square in the plan ; but they have been 

 found to be less obstructive to the training of trees, when rounded at the angles (a) ; or 

 angular (b), and either hollow, or effected by deviation (c). The same remark will 

 apply to piers formed partly to support the wall, but principally as in the gardens laid 

 out by London and Wise, Bridgeman, &c. for sheltering the fruit-trees. Where train- 

 ing is not a leading object, a thin deep projection (rf) is much stronger as a whole, than 

 the clumsy square piers generally formed by routine practitioners. 



1573. Sheltering jners were formerly, in some cases, made of such- a width and depth 

 as to contain a niche for training a vine, and, in that case, they were frequently raised 

 above the coping of the wall. Examples of such piers exist in the walls of the kitchen- 

 garden at Claremont, built from the designs of Brown, and at Hatton in Scotland, built 

 after a design by London and Wise. 



247 



1574. Arched, niched, or recessed walls (fig. 247.) were contrived for the same pur- 

 pose by Switzer, and, at least, had a massive imposing effect to the eye. Such walls were 

 generally heated by flues, and formed in fact the intermediate link in the progress of im- 

 provement between hot- walls and forcing-houses. 



1575. Trellised ivalls are sometimes formed when the material of the wall is soft, as in 

 mud walls ; rough, as in rubble-stone walls, or when it is desired not to injure the face of 

 neatly finished brick-work. Wooden trellises have been adopted in several places, espe- 

 cially when the walls are flued. Wire has also been used, and the following mode has been 

 adopted by C. Holford, an ingenious horticultural amateur at Hampstead : " I affix cop- 

 per wires from the top to the bottom of the wall, in a perpendicular direction, secured at 

 each end by a small iron hook, two iron stair-staples are also driven in over the wires, at 

 equal distances, to keep them nearly close to the wall. The wires may be placed at six 

 to eight inches' distance from each other. The branches and shoots are fastened by means 

 of thin twine, which is first tied to the wire with a single knot, and then round the shoot 

 more or less tight, according as it may be required to check or encourage the circulation 

 of the sap ; with a very little practice this may be done with great expedition. The 

 wire which I have used is of the substance measuring about twenty yards to the pound 

 weight, and as it does not oxydate by exposure to the atmosphere, will not require paint- 

 ing, and will last for years. *The expense is about one penny per yard. I have not found 

 the peaches and nectarines to be at all retarded by this mode of training." (Hort. Trans. 



v. 569.) 



1576. Espalkr rails are substitutes for walls, and which they so far resemble, that trees 



