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AN ECONOMICAL PIT FOR FORCING DAHLIAS, &c. 



BY DAVID CAMERON, A.L.S., Botanic Garden, Edgbaston. 



An economical pit for the forcing of dahlias, tender annuals, striking cuttings, 

 and other purposes, may be made by building a dry cellar of from four to six feet 

 in depth under an ordinary pit, and of the same length and width as the pit. 

 There should be a close door at one side, and an aperture at each of the other 

 ends six inches square. 



Over the cellar across the pit, place either iron or wooden bearers, upon 

 which lay large slates, closely cemented, to form the bottom of the pit. Place 

 upon the slates about nine inches of dry sawdust, for plunging pots of dahlias, or 

 whatever is intended to be forced. Other substances besides sawdust will do, 

 such as sand, or half-decayed tan, but sawdust is preferable, being an excellent 

 substance for retaining heat. 



When the forcing is to commence, stop the apertures of the cellars with 

 straw, or hay, and get one or more loads of quite fresh stable dung, according to 

 the size of the pit. The dung must be well shaken up, and thrown into the 

 cellar in a heap. The steam arising being pent up in the cellar, gives a genial 

 heat to the sawdust, equal to that of a dung hotbed, and without the moisture 

 being imbibed, which is so destructive to some plants early in the spring, and 

 more particularly to dahlias. 



When the heat is getting too high, the apertures may be opened a little, so 

 as to lessen the heat, and when getting too cold, the manure must be taken out, 

 and watered if too dry. If decayed too much, the rotted portion must be put 

 aside for hotbeds, and fresh added to that in the cellar. 



It will be perceived that this place is to make use of the heat arising from 

 stable manure during the process of bringing it to a fit state for hotbeds, which 

 by the usual process is lost. Upon commencing a pit of this construction for the 

 first time, the safest way is to put in the sawdust and dung, and watch the heat 

 until the operator can comprehend the management ; a week's practice will 

 teach him more than a page of directions. The pit is serviceable for all the 

 purposes of a cold pit when not worked by dung. 



ON THE ACCLIMATATION OF PLANTS. 



Every degree of latitude of the globe which has as yet been visited by 

 civilised man, is found to be furnished with its own peculiar tribes of the vegetable 

 kingdom. In the Arctic regions, mosses, and lichens, and other minute genera, 

 are only found to prevail. And in the low latitudes, under the direct influence 

 of the sun, the most magnificent herbs and gigantic trees clothe the face of the 

 earth. The only barren spots are the Arctic and Antarctic storm-washed rocks, 

 and the sirocco-driven sands of central A frica. 



VOL. II. NO. XVIII. AUGUST. N 



