HOT 



HUM 



HORTUS SICCUS. An herbari- 

 um, a collection of dried plants. 



HOT-BED. See Frame. 



HOT-HOUSE. A glazed structure, 

 sufficiently high to allow persons to 

 enter, and with conveniences for the 

 production of artificial lieat. The 

 means of healing are various : some 

 depend upon dung pits constantly re- 

 newed, others upon flues running in 

 the walls, and conveying the hot air 

 of a furnace. Steam is also convey- 

 ed by iron and copper pipes, and made 

 to circulate several times through 

 the house, especially under the beds. 

 Hot water is also conveyed from a 

 boiler round the house and back, so 

 as to maintain a constant circulation, 

 the boiler being provided with a safe- 

 ty-valve. The direct introduction of 

 steam from a boiler through an open 

 pipe is occasionally used as an eco- 

 nomical way of heating the house 

 when the plants are adapted to a very 

 moist air. 



The arrangements of the hot-house 

 are various, according to the object 

 in view. The roof usually sustains 

 grapes ; the highest wall, tigs, apri- 

 cots, early peaches, nectarines, and 

 choice fruits : in the centre is arran- 

 ged a rising frame containing the ex- 

 otics, whicii require heat during win- 

 ter, or the ground may be used as a 

 place to forward vegetables. The 

 walk is around the central stand. The 

 height and dimensions will depend 

 upon the plants protected. 



HOTTENTOT BREAD. Tamus 

 (Tesludinaria) clephantipes. A South 

 African climbing perennial, produ- 

 cing an immense above-ground tuber, 

 very similar to the j'am in flavour. 

 It forms a large portion of the food 

 of the natives. 



HOT-WALLS. Walls in which 

 heat circulates for the advancement 

 of fruit, and ripening of the wood in 

 the fall. They are made by conduct- 

 ing flues from a furnace at various 

 heights, or back and forth, and ter- 

 minating in a chimney ; by enclo- 

 sing steam pipes, or, what is much 

 better, bv building the wall hollow 

 throughout, binding the two sides to- 

 gether occasionally by cross bricks 



' or stones, and a coping, and passing 

 a large hot-water pipe along the bot- 

 tom between the sides : the heat 

 from this rises upward, and produces 

 an equal temperature throughout the 

 wall. 



Hot -walls are much assisted by 

 a moveable arrangement of glazed 

 sashes, which can be set up to pro- 

 tect the trees from frost in early 

 spring, and may be removed during 

 summer. 



Ordinary walls, painted of a dark col- 

 our, and looking to the south, become 

 heated by ten to twenty degrees high- 

 er than the adjacent grounds during 

 summer, and therefore advance the 

 ripening of fruits considerably, espe- 

 cially if all the leaves lying around 

 the fruit be removed, which shade it 

 from the sun or wall. The introduc- 

 tion of reflecting surfaces of white 

 wood or sheet tin, so as to concen- 

 trate light and heat on walls, would 

 doubtless much advance the maturi- 

 ty of fruits. Such reflectors might be 

 moveable, made very light, and read- 

 ily adjusted to heat any particular 

 wall. 



HOUXD. The dogs of chase are 

 so called. 



HOUND'S TONGUE. The genus 

 Cynoglossum : rough-leaved weeds of 

 little value. 



HOUSELEEK. Exotic plants of 

 the genus Scmpervivum, with succu- 

 lent leaves, which are mucilaginous. 



HOVEL. A shed for cattle, sheep, 



HOVEN, HOOVE. See Oxen, Dis- 

 eases of. 



HUCKLEBERRY. Whortle- 

 berry. 



HUMAN F^CDS. See Night-soil. 

 I HU.MATES. Salts of humic acid. 

 See Humus. 

 HUMECTATION. Moistening. 

 HUMERUS. The upper bone of 

 the arm. 



HUMIC ACID. See Humus. 

 ! HUMIFUSUS, HUMIFUSE. 

 Spreading over the ground, procum- 

 bent, like the stem of the melon, 

 ' sweet potatoe, &c. 



HUMILIS. Low, humble, applied 

 , to small species. 



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