WAL 



[ 917 ] 



WAT 



inches in breadth, by placing the bricks 

 edgewise so as to form two facings, they 

 are laid in good mortar, and the joints 

 carefully finished. They are placed 

 alternately with their faces and ends to 

 the outsides, so that every second brick 

 is a tie, and in each succeeding course 

 a brick with its end outwards is placed 

 on the centre of one laid lengthwise on 

 either side. The top of the wall must 

 be covered with a coping of stone or 

 bricks projecting eight inches. It is 

 strengthened at every twenty feet by 

 piers of fourteen -inch work, built in the 

 same manner, with bricks laid on edge. 



In every instance a wall should never 

 be lower than eight feet. The thick- 

 ness usually varies with the height of 

 the wall being nine inches, if it is not 

 higher than eight feet ; thirteen-and-a- 

 half inches, if above eight and under 

 fourteen feet; and eighteen inches, 

 from fourteen up to twenty feet. 



Inclined or Sloping Watts have been 

 recommended, but have always failed 

 in practice. It is quite true that they 

 receive the sun's rays at a favourable 

 angle, but they retain wet, and become 

 so much colder by radiation at night 

 than perpendicular walls, that they are 

 found to be unfavourable to the ripen- 

 ing of fruit. 



The Flued-ivall or Hot- wall is gene- 

 rally built entirely of brick, though 

 where stone is abundant and more eco- 

 nomical the back or north side may be 

 of that material. A flued wall may be 

 termed a hollow wall, in which the 

 vacuity is thrown into compartments 

 a a a a, to facilitate the circulation of 

 smoke and heat, from the base or sur- 

 face of the ground, to within one or 

 two feet of the coping. Such walls are 

 generally arranged with hooks inserted 

 under the coping, to admit of fast- 

 ening some description of protecting 

 covers, and sometimes for temporary 

 glass frames. A length of forty feet, 

 and from ten to fifteen high, may be 

 heated by one fire, the furnace of 

 which, &, being placed one or two feet 

 below the surface of the ground, the 

 first course, or flue, c, will commence 

 one foot above it, and be two feet six 

 inches, or three feet high, and the 

 second, third, and fourth courses, d, e,f, 



narrower as they ascend. The thick- 

 ness of that side of the flue, next the 



south or preferable side, should for the 

 first course, be four inches or brick and 

 bed, and for the other courses, it were 

 desirable to have bricks cast in a smaller 

 mould : say for the second course three, 

 for the third two - and - three - quarters, 

 and for the fourth two-and-a-half inches 

 in breadth. This will give an oppor- 

 tunity of bevelling the wall, and the 

 bricks being all of the same thickness, 

 though of different widths, the exter- 

 nal appearance will be everywhere the 

 same. Enc. Gard. 



WALNUT. Ju'glans. 



WARDIAN CASE. See Glass Case. 



WA'BREA. (Named after F. Warrc, 

 a botanical collector. Nat. ord., Orchids 

 [Orchidace&3]. Linn., "20-Gynandria 1- 

 Monandria. Allied to Grobya.) 



Stove orchids grown in baskets. See Orchids. 



W. bidenta'ta (two-toothed-fr>/?ed). Purple, 



Avhite. September. Caraccas. 1843. 



cya'nea (\Aw-lipped). 1. White, blue. 



August. Columbia. 1843. 



rubc'scens (reddish). Red. April. Brazil. 



1838. 



tri'color (three-coloured). 2. Yellow, purple. 



August. Brazil. 1843. 



WATER. The best for the gardener's 

 purpose is rain water, preserved in 

 tanks sunk in the earth, and rendered 

 tight either by puddling, or bricks 

 covered with Parker's cement. To 

 keep these tanks replenished, gutters 

 should run round the eaves of every 

 structure in the garden, and communi- 

 cate with them. Every hundred cubic 

 inches of rain water contains more than 

 four cubic inches of air, of which more 

 than half are carbonic acid gas, and 

 the remainder nitrogen and oxygen, in 

 the proportion of sixty-two of the 

 former to thirty-eight of the last named. 



