H0T 



[442] 



HOU 



as may be necessary. The outer wall 

 supports the lights. For the conve- 

 nience of fixing the dung, it is best to 

 fill half of the chamber at the com- 

 mencement, before the branches, mould, 

 <fcc., are put in. 



Hot-Water Beds. If hot water be the 

 source of heat, the following sketch of 

 the bed and frame employed by Mr. 

 Mitchell, at Worsley, is about the best 

 that can be employed. The objects kept 

 in view when it was constructed, were 

 1st. A circulation of air without loss of h eat. 

 2nd. A supply of moisture at command, 

 proportionable to the temperature. 3rd. 

 A desirable amount of bottom-heat. 4th. 

 A supply of external air (when necessary) 

 without producing a cold draught. 



The method by which the first of these 

 is accomplished will be understood by 

 referring to the section, in which a is the 

 flow-pipes, b b I the return-pipes in the 

 chamber A. It is evident that, as the 

 air in the chamber becomes heated, it 

 will escape upwards by the opening c, 

 and the cold air from the passage B will 

 rush in to supply its place; but the 

 ascending current of heated air, coming 

 in contact with the glass, is cooled, de- 

 scends, and entering the passages, passes 

 into the chamber A, where it is again 



heated; and thus a constant circulation 

 is pro'duced. In order to obtain the 

 second object, to some extent are combined 

 the tank-and-pipe systems. The flow- 

 pipe a is put half its diameter into the 

 channel c, which, when filled with water 

 (or so far as is necessary), gives off a 

 vapour, exactly proportionable to the 

 heat of the pipe and pit. 



The third requisition is produced by 

 the surrounding atmosphere and heating 

 materials. The fourth is accomplished 

 simply by lowering the upper sash ; the 

 cold air thus entering at the top only, 

 falls directly into the passage B, and 

 passes through the hot chamber be- 



fore coming in contact with the plants. 

 When the heat in the chamber is 95, in 

 the open space over the bed it is 71 ; in 

 the bottom of the passage only 60 ; and 

 in the mould in the bed it is 80. The 

 amount of vapour is regulated with the 

 greatest facility, even from the smallest 

 quantity to the greatest density. Gard. 

 Chron. 



HOTHOUSE. See STOVE. 



HOTTENTOT BREAD. Diosco'rea. 



HOTTENTOT CHEEKY. Cassi'ne Mauro- 

 ce'nia. 



HOTTENTOT FIG. Hesembrya'nthemum 

 edu'le. 



HOTTO'NIA. Water Violet. (Named 

 after P. Holton, a Dutch botanist. Nat. 

 ord., Primeworts [Primulacess]. Linn., 

 5-Pcntandria \-MonogyniaS) 



A hardy aquatic or marsh plant. Divisions in 

 spring ; ponds or ditches. 

 H, pulu'stris (marsh"), 1. Flesh. August. England. 



HOT WALL is a hollow wall, the interior 

 air being so heated by flues or hot water 

 as to keep the bricks of which its faces 

 are composed so warm as to promote the 

 ripening of the wood and fruit trained 

 against them. See WALL (Fhted). 



HOT WATER, as a source of heat for 

 gardening purposes, is preferable to any 

 other for large structures. In these it 

 is less expensive, and in all it is more 

 manageable and less troublesome than 

 any other. See GREENHOUSE, HOTBED, 

 and STOVE. 



HOULLE'TIA. (Named after M.Houllet, 

 a French gardener. Nat. ord., Orchids 

 [Orchidacese]. Linn., 2Q-Gynandrict 1- 

 Monandria. Allied to Stanhopea.) 



Stove orchids. Division of the plant; peat, 

 broken pots, charcoal, and rotten wood; plants 

 elevated above the pot, or in a shallow basket. 

 Summer temp., 60 to 90; winter, 50 to 60. 

 H. Brocklehurstia'na (Mr. Brocklehum's). 2. 

 Brown, yellow. June. Brazil. 1841. 



vittu'ta (striped). 1. Brown, yellow. June. 



Brazil. 1841. 



HOUND'S TONGUE. Cynoylo 1 ssum. 



HOUSELEEK. Sempervi'vitm. 



HOUSTO'NIA. ( Named in honour of Dr. 

 W. Houston, an English botanist. Nat. 

 ord., Ginchonads [Cinchonacese] . Linn., 

 4,-Tctrandria I-Monogynia.) 



Hardy herbaceous perennials, from North 

 America. Division in spring ; sandy loam and 

 peat ; beautiful for small beds and rock-worka. 

 This genus, should be added to Bouvardia. 

 H. albiflo'ra (white-flowered). White. June. 1823. 



ceeru'lea (blue). . Blue. June. 1/85. 



cilia'ta (hair-fringed). Whitish. July!/ 



longifo'lia (long-leaved). J. Scarlet. 



