396 Transactions of the London Horticultural Society. 



the division where the rows were at that distance were the most uniform in 

 their appearance. The important inferences to be drawn from this were after- 

 wards shown by the result. 



On the 26th of September the whole crop was taken up, freed from mould, 

 and weighed. Where the rows were only 6 in. apart, a number of the new 

 potatoes were partially decayed, and a very large proportion was too small to 

 be fit for use. The most uniform size was obtained from the division where 

 the rows were 2 ft. apart. 



The result of this experiment Dr. Lindley considers " the most interesting 

 yet obtained, for it not only reduces to something like a demonstration the 

 superiority of sets over whole tubers, but it shows that the crop will be greater 

 where the distance between the rows is most in accordance with the average 

 height of the potato stems ; and that, if we take the minimum height, which 

 in this variety is l^ft., although the crop may be the most promising 

 while growing, it will, in reality, be smaller than when the branches are less 

 dense. 



" Thus the most uniform crop of stems, in this experiment, v/as in the 

 division where the rows were I^ ft. apart ; but the crop in that division was 

 less by 1 ton 3 cwt. 97 lb. than where the rows were 2 ft, apart, that is, equal 

 to the average height of the stems," 



The neat return of the single eyes, where planted at 2 ft, apart between 

 the rows, was at the rate of 24 tons per acre ; at 18 in. between the rows, 22 

 tons per acre; at 2 ft. 6 in., 16 tons; and at 6 in. between the rows, 16 tons. 

 The produce in the neighbourhood of London, as estimated in diiFerent 

 places, is from 12 to 15 tons, the rows being from 22 in. to 24 in. apart, and 

 the distance of the sets in the frame 6 in. to 9 in. The depth at which the 

 sets were planted varied from 4 in. to 8in, ; but 9 in. is the depth that Mr. 

 Knight and Dr. Lindley recommend. 



65. Report on the Special Exhibitions of the Horlicultui'al Society of London. 

 By G. Bentham, Esq., F.L.S,, Secretary, 



This contains a list of the persons who received medals from the year 

 1832, when the exhibitions commenced, to the end of the year 1834. 



VOL. IL 



1. Meteorological Journal, S^c. By Mr. Robert Thompson. 



2. Upon the Causes of the Diseases and Deformities of the Leaves of the Peach 



Tree. By T. A, Knight, Esq., F,R,S., Pres, Read July 15, 1834. 



" Every gardener knows that the leaves of peach trees frequently be- 

 come diseased and deformed, owing to the operation of two perfectly distinct 

 causes ; one being obviously the depredations of insects, and the other being 

 generally, I believe universally, supposed to be frost. In the last-mentioned 

 case, the leaves, if suffered to remain upon the trees, continue to grow, and in 

 part to perform their office of generating the living sap of the tree ; but the 

 whole, or nearly the whole, of the fluid thus created is expended in their own 

 deformed and morbid growth. In unfavourable situations, such as mine un- 

 fortunately is, a large portion of the first-formed leaves is frequently rendered 

 useless, or worse than useless ; and I do not recollect a single season in 

 which a very large part, and sometimes all the early foliage of my peach and 

 nectarine trees, which almost wholly occupy the entire south wall of my gar- 

 den here (Downton Castle), has not been destroyed or rendered useless, 

 previously to the present season. 



" In the autumn of the year 1831 a small nectarine tree, which grew in a pot 

 in my peach-house, was removed from it, and planted in the open air, amongst 

 other trees of the same species. A few of the species of scale insect which 

 is the usual pest of the peach-house were then transferred to the peach treesi 



