130 VICE-SECEKTAKY ON SIMMONS'S PATENT HYGROMETER. 



" A slip of wood is cut transversely with the grain, of about, or varying 

 from 6 to 1 7 inches in length, according to the absorbing property of the wood 

 employed ; one end of the slip (BBB) secured to the frame or fabric (AAAA), 

 at pin (C) ; but on the other end of the slip (B) is fixed a pulley (D), which is 

 kept in its position by a line (a a), one end of which is secured to the frame or 

 fabric by the hook (b), and passing through the pulley (D) affixed to the slip 

 (B), thence round a small pulley (t) of about two-tenths of an inch in diameter, 

 the axis of which carries a hand (E) to indicate on a dial (FF); inside, and 

 affixed on the same small pulley, is another pulley ((/) of the same size, and 

 on the same axis, having a line (e) on it, drawn by a weight or spring (G), 

 which pulls up the slip (B) tight ; yet by its tension allows the dilation or 

 contraction of the slip in its changes, giving motion to the hand indicating 

 on the dial. 



" The improvement claimed in this instrument consists in adapting the 

 changes produced by moisture upon wood with a line through the medium 

 of pulleys to give a legible indication to a hand on a dial, which renders it 

 portable and convenient for scientific purposes and domestic usefulness." 



XVIII. — On the Culture of Epiphyllum truncatum. By Mr. 

 John Green, C.M.H.S., Gardener to Sir Edmund Antrobus, 

 Bart., F.H.S. 



(Communicated with a very fine specimen of the plant, for which a Bank- 

 sian medal was awarded, January 20, 1846.) 



To propagate the Epiphyllum truncatum, I prepare young 

 healthy stocks of Cereus speciosissimus, and engraft them with the 

 above in March, from one to two feet above the surface of the 

 pots. I grow them in the stove till they are sufficiently large 

 for flowering, which should be in about eighteen months from the 

 time they are grafted. In the autumn of their second summer's 

 growth I remove them from the stove to a cool airy part of the 

 greenhouse, or, if the weather is fine, place them out on a south 

 border out of doors; and, as winter advances, I diminish the 

 quantity of water till they become quite dry. They remain in 

 the greenhouse at rest till they are required for forcing. 



Those that I require to flower first are removed back to 

 the stove early in spring. As soon as they have matured the 

 first growth, I place them in any exposed part of the garden. 

 This change causes them to set flower-buds at the point of every 

 shoot. As soon as the flower-buds are well established I place 

 the plants in a warm shady part of the greenhouse, where they 

 will flower profusely by the early part of October. 



By removing the plants successively from their winter quar- 

 ters to the forcing-house, and treating them as above mentioned, 

 a succession of fine plants can be kept in bloom from October to 

 March. 



To those who esteem a collection of winter flowers, nothing 

 can be more desirable than this Epiphyllum truncatum, E. vio- 



