272 ON AN IMPROVED MODE OP CULTIVATING THE MELON. 



external air ; that would pass into the cavity of the wall, and escape into 

 the house through passages immediately beneath the coping of such walls ; 

 and warm air might be thus at all times freely introduced with much 

 advantage to the plants, and in winter with a very considerable diminution 

 of the expenditure of fuel ; and indeed I feel perfectly confident that, by 

 the proper application of hollow walls in a shed behind a hot-house, every 

 kind of forcing culture might be successfully carried on without the use 

 of a particle of fuel, and with a moderate quantity only of bark, or leaves, 

 or other fermenting material. 



LII. AN ACCOUNT OF THE INJURIOUS INFLUENCE OF THE PLUM- 

 STOCK UPON THE MOORPARK APRICOT. 



[Read before the HORTICULTURAL SOCIETY, April }st, 1823.] 



IN the selection of stocks for the reception of grafts or buds of different 

 species of fruit-trees, the English gardeners and nurserymen generally 

 suppose that, when a stock is employed upon which the inserted graft, or 

 bud, will grow freely and permanently, everything which is expedient or 

 beneficial is done. It is even supposed that cases exist in which much 

 advantage is obtained by the use of a stock of a different species, and 

 even of a different genus. The peach and nectarine trees are thus 

 generally believed to succeed better upon the plum than upon the native 

 stock ; and some varieties of the pear have been pronounced by Miller 

 to acquire their highest state of perfection upon quince-stocks ; but I 

 suspect that Miller formed his opinion rather upon the external colour 

 and size of the fruit than upon its intrinsic qualities, and decided, as 

 every gardener who had honestly sent the best produce of his garden to 

 his employer's table would probably have done, that the sample of his 

 fruit which exhibited the finest colour and the largest size was the best ; 

 and it is well known that a young pear-tree, when growing upon a 

 quince-stock, affords fruit of brighter colours, and, in some varieties, of 

 larger size ; and that the tree is rendered more governable, and therefore 

 more productive, when trained to a wall. Taking off a circular ring of 

 bark, or what is called ringing the stock, gives a similar increase of size 

 to the fruit, and of brilliancy to its colour ; but its pulp is rendered much 

 less succulent and melting ; and I suspect that the effects of a quince- 

 stock, and of ringing, will be found very nearly similar, each operating 



