424 



Transactions of the Horticultural Society. 



produce more variety than a 

 common sloping series of 

 shelves. This arrangement also 

 displays more surface to the 

 light and air than the common 

 mode. " It is now about ten 

 years since the idea of making 

 these stages struck me, and I 

 am happy to say they have an- 

 swered my most sanguine ex- 

 pectations, and have met with ^ 

 the approbation, not only of C 

 my employer, but of most persons who have seen them." 



The back wall is covered with creepers, there is a large 

 niche or alcove at one end, and a narrow border in front ; the 

 flues, span-roof, &c. are in the usual way. {Jig. 87.) 



17. Upon the beneficial Effects of protecting the Stems of Fruit 

 Trees from Frost in early Spring. By Thomas Andrew Knight, 

 Esq. FR.S. &c. President. Read February 1. 1825. 



Circumstances have led Mr. Knight to believe, that when- 

 ever a very large portion of the well-organised blossom of 

 fruit trees falls off abortively in a moderately favourable season, 

 the cause of the failure may generally be traced to some pre- 

 vious check which the motion and operation of the vital fluid 

 of the tree has sustained. A severe frosty night, or very cold 

 winds, during the barking season, is known to give such a 

 check to the flow of sap in the oak tree, as to prevent it from 

 being separated by the peelers till the return of milder 

 weather. 



" Neither the health of the tree, nor its foliage, nor its blossoms, 

 appear to sustain any material injury by this sudden suspension of 

 its functions ; but the crop of acorns invariably fails. The apple and 

 pear tree appear to be affected to the same extent by similar degrees 

 of cold. Their blossoms, like those of the oak, often unfold perfectly 

 well, and present the most healthy and vigorous character ; and 

 their pollen sheds freely. Their fruit also appears to set well ; 

 but the whole, or nearly the whole, falls off just at the period 

 when its growth ought to commence. Some varieties of the apple 

 and pear are much more capable of bearing unfavourable weather 

 than others, and even the oak trees present, in this respect, some 

 dissimilarity of constitution. 



" It is near the surface of the earth that frost, in the spring, ope- 

 rates more powerfully, and the unfolding buds of oak and ash 

 trees, which are situated near the ground, are not unfrequently 

 destroyed, whilst those of the more elevated branches escape 

 injury; and hence arises, I think, a probability that some advan- 



