COPINGS FOR GARDEN WALLS. 



69 



than the sloping wall : the freestone, at 

 the same hour, 5° colder than the sloping 

 wall, or 2° below the whinstone. At six 

 in the afternoon the sloping wall was 2° 

 warmer than the freestone and brick 

 walls, and 5° warmer than the whinstone 

 wall, which at this hour was found to be 

 the coldest of all. During frosty weather, 

 and when hoar-frost forms, the sloping 

 wall becomes 2° or 3° colder during the 

 night than any of the others. These 

 experiments are the result of calcula- 

 tions by the thermometer. It would be 

 equally interesting to have a statement 

 of the periods of fruit ripened from the 

 same walls, taking the same year. 



The best stone walls are those that 

 are built in regular courses ; but these 

 courses should not exceed 9 inches in 

 thickness, nor be less than 3, the thick- 

 ness of an ordinary brick. The stones 

 should be squared and hammer-dressed, 

 or picked — a way of dressing the surface 

 with a pick or pointed end of a hammer ; 

 or they may be done in broached ashlar, 

 with droved margins, (or draughted and 

 broached) — that is, wrought round the 

 joints with a chisel, about three-fourths 

 of an inch on the face, and the remaining 

 part of the face roughly done with the 

 pick, as in fig. 39. This style of building 



Fig. 39. 



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 iii'-i^jMnTllil'll %W: 



fpfti 



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!',;. 



Hill lll'llllllilllll'llll 



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makes beautiful walls, particularly if the 

 mortar joints are properly pointed and 

 drawn clean off. 



The following materials are more or 

 less used for garden walls ; but as they 

 will be noticed more in detail in their 

 respective places, we shall only enumerate 

 them here — concrete, clay, slate, wood, 

 pavement, iron plates, reeds, flints, scoria, 

 and latterly glass. 



§ 4. — COPINGS FOR GAKDEN WALLS. 



Great difference of opinion exists as to 

 the benefits derived from projecting cop- 

 ings. We believe that the majority 

 agree with us in preferring them to be of 

 a portable description, as their presence 



is as great a benefit during spring as it 

 would be injurious during summer. All 

 walls require to be coped sufficiently to 

 exclude the wet from penetrating into 

 them, as much as a house requires to be 

 thoroughly roofed. This is, we believe, 

 admitted by all. The extent of projec- 

 tion is the question at issue. 



The advantage is admitted by Leslie in 

 art. "Cold," Encyc. Brit., Wells "On 

 Dew," &c. The Comte Lelieur, and 

 most of the French cultivators and 

 writers, approve of projections nearly a 

 foot in breadth — most of which, however, 

 are permanent— and that on walls not 

 exceeding 10 feet in height. At Mon- 

 treuil, and most of the celebrated peach 

 gardens round Paris, the projection is 

 from 4 to 5 inches; and, according to 

 "The Pomona Francaise," on the walls 

 at Thomery, where the finest grapes are 

 grown, the copings project 9 or 10 inches 

 over walls which do not exceed 8 feet in 

 height. 



Lawrence, Millar, Forsyth, Atkinson, 

 Nicol, &c, recommend portable copings, 

 as tending to protect the blossom in 

 spring, which are to be removed in sum- 

 mer, as they would then be injurious by 

 excluding rain, light, and air. 



We may safely conclude that portable 

 copings are preferable to permanent 

 ones, so far as protection to the trees is 

 concerned, and that their utility is not 

 only confined to spring, but embraces 

 autumn also. The following suitable 

 remarks on this subject by Mr Errington, 

 in "Gardeners' Chronicle," 1846, (p. 821,) 

 although not quite in accordance with 

 our own experience, are deserving of 

 especial attention, as coming from so 

 excellent a source. " The benefits of cop- 

 ings in September and October," he says, 

 " are perhaps even greater than in spring. 

 I think it would not be asserting too 

 much to say, that at that period alone, 

 in effect, they add a fortnight to the 

 length of our summer ; or, in other words, 

 they produce results equivalent to a fort- 

 night's fine weather. The rationale of 

 these operations is," he thinks, "the in- 

 terception of radiation. Be that as it 

 may, a wall with a good coping will be 

 found warmer after sunset, for some 

 hours, than one without a coping. The 

 objections in point of excluding the dews 

 and rains are of no weight, as it is quite 



