POLIANTHES. 



246 



POLMAISE HEATING. 



angled seeds ; tlie type being Com- 

 trttum purjjurcum {Poivrea coccl- 

 nea. Dec). For the culture, see 

 Combee'tum. 



PoLEMo'NiUJr. — PoJemonidcece. 

 — Greek Valerian. — The common 

 wild species, P. ccenlleum, is very 

 abundant on the dry sandy banks 

 in the lanes near Shenstone, in 

 Staffordshire, where it is called 

 Charity, though its common name 

 in other parts of England is Jacob's 

 Ladder. All the kinds succeed best 

 in gravelly or chalky soil, and they 

 are all increased by dividing the 

 roots. 



Polia'nthes. — Hemerocallldece. 

 — The Tuberose. — A bulbous-rooted 

 plant, a native of the East Indies, 

 remarkable for its highly odoriferous 

 white flowers. The bulbs are im- 

 ported from Italy, where they are 

 grown for exportation as Hyacinths 

 are in Holland. They require to 

 be brought forward in a fi-ame or 

 pit ; and when coming into flower, 

 they should be removed to a green- 

 house or any cool airy apartment, 

 where they will diffuse a powerful 

 fragrance, which to some is grate- 

 ful and to others oppressive. They 

 should be potted in sandy loam ; 

 and if the bulbs are intended to 

 flower the second year, the plants 

 should be replaced in heat close to 

 the glass, and kept there till the 

 leaves begin to decay ; after which 

 the bulbs may be treated like those 

 of the Hyacinth. It is rarely, how- 

 ever, that this can be done with 

 success, and it is therefore better 

 to thi'ow the plants away when they 

 have done flowering, and purchase 

 fresh bulbs every year. In plea- 

 sure-grounds of limited extent, a 

 few plants of the Tuberose in flower, 

 distributed over them at distances 

 of fifty or one hundred yards plant 

 from plant, will diffuse a most de- 

 lightful fragrance in the summer 



and autumnal evenings ; a circum- 

 stance well imderstood in the public 

 gardens in the vicinity of Paris. 



PoLMAiSE Heating. — The prin- 

 ciple of this mode of heating is to 

 imitate the natural atmosphere of a 

 hot climate by allowing the plants 

 a constant change of heated air ; 

 and it differs from Penn's system, 

 with which it has been compared, 

 in supplying a constant current of 

 fresh air, instead of merely a.llow- 

 ing the same air to circulate through 

 the house again and again. This 

 mode of heating was first used in 

 a stove erected at Polmaise, in Stir- 

 lingshire ; but afterwards the stove 

 was very much improved by the late 

 Mr. Meek ; and various modifica- 

 tions of the system have been since 



The annexed desciiption and 

 figure of Polmaise Heating are 

 copied from the Gardeners' Chron- 

 icle for Feb. 21, 1846. " Let the 

 outer shaded lines A A (in fig. 41) 

 represent the walls of a span-roofed 

 hothouse, and B those of a hot 

 chamber, the sides and roof of 

 which it will be well to line with 

 some non-conducting material ; the 

 second shaded lines within A re- 

 present the walls of a bark bed. 

 The portion of the floor marked 

 C C, beneath the bark bed and ex- 

 tending towards the hot chamber 

 in the direction of the dotted lines, 

 is to be laid hollow, and its sup- 

 ports so arranged as to allow of free 

 atmospheric communication beneath 

 it. Between the wall of the bark 

 bed (extending round its three sides), 

 and the lines D D D D, is an open- 

 ing through which the air of the 

 house may have free passage into 

 the space beneath. The an-ows in- 

 dicate the direction of the atmos- 

 pheric currents passing beneath the 

 floor and the wall of the house into 

 the hot air chamber at E E, and 



