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LVI. Extract of a Letter from Sir Brooke Boothby, Bart, 

 to Sir John Sinclair, Bart, dated Brussels, 10th January, 

 1816; regarding some Improvements in Gardening. Commu- 

 nicated by Joseph Sabine, Esq. F. R. S. fyc. Vice President. 



Read April 2, 1816. 



I cannot furnish you with any very accurate observations 

 regarding the subject I mentioned to you, the other day ; 

 but, I believe, it has been understood, that at certain periods, 

 preventing, or retarding, the ascent of the sap, tends to pro- 

 duce and ripen the fruit. An abundance of sap is found 

 to increase the leaf buds, and decrease the flower buds. A 

 process to retard the sap has long been employed, with the 

 greatest success, in the gardens of Montreuil at Paris, which 

 you will find well described in the treatise on the subject by 

 the Abbe Schobal, which is easily procured. His practice, 

 thereby, is to divaricate the sap as near the root as may be, 

 by cutting off the main stem, and training two lateral 

 branches, from which his wall is to be filled. 



" The other process of interrupting the rising of the sap 

 by separating the bark, has,' I believe, been long in practice 

 in Vine forcing-houses ; this is done when the Grapes are full 

 grown, and is found to assist the bark in diminishing the 

 aqueous, and encreasing the saccharine juice. 



" I mentioned to you yesterday, that I had succeeded in 

 banishing, entirely, the red spider, &c. from my hot-house 

 and green-house at Ashbourne, by the simple process of 



