Transactions of the Horticultural Society. 



71 



to do. He therefore got a pit (fig. 8.) in which he built 

 two flues (a, a,) and 

 supported over thena, on 

 brick props (c), a floor- 

 ing of pavement, co- 

 vered with a layer of 

 gravel and sand (d), on 

 which to place the pots ; 

 at the sides were open- 

 ings {b, b), to admit the 

 heated air from below to 

 to warm the atmosphere 

 of the plants ; the up- 

 per level of the platform 

 on which the plants stand, is nearly on a level with the ex- 

 ternal surface (e, e). The pots of plants are set on the sand, 

 so that when moisture is added either to it or to the 

 plants, it causes a fine gentle steam to arise through the 

 whole of the pit, which can be regulated at pleasure, by ad- 

 ding more or less fire according to the season or other cir- 

 cumstances. After nearly three years experience, Mr. Stew- 

 art is "fully convinced" that tan is quite unnecessary not 

 only as a source of bottom heat, but even for rooting the 

 crowns and suckers. " The temperature kept during the 

 spring and summer is from eighty to a hundred degrees 

 through the day, and as low as from sixty-five to sixty degrees 

 during the night ; in the autumn and winter it is as low as 

 fifty-five or fifty degrees." He has no hesitation in stating 

 that where coals are moderate in price, it is the cheapest plan 

 he has seen adopted ; and he sends the particulars to the hor- 

 ticultural society, " in hopes that they may assist in establish- 

 ing" Mr. Knight's views on the subject of cultivating the 

 pine-apple. 



63. Description of a Pear Tree, on which the Operation of Reverse 

 Grafting has been performed. In a letter to the Secretary. By 

 Mr. William Balfour, Gardener to Earl Grey, at Howick, in 

 Northumberland. Read Nov. 4. 1823. 



The usual defect of horizontally trained trees, viz. : barren- 

 ness to some distance on either side of the main stem, led Mr. 

 Balfour to grafting reversely on the under side of the horizon- 

 tal branches. The scions for this method are inserted in 

 the same manner as in rind grafting ; they take freely and 

 bear abundantly. The advantages of the plan are, curing 



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