- :'..'." the Boulevards. 645 



Of Messrs. Loddiges's specimens of all of these we have lately- 

 had portraits taken for our forthcoming Arboretum Britannicum: 

 none of them are under 15 ft. high, and few of them above 

 30 ft. ; the ultimate heights they will attain are from 30 ft. to 

 J 00. If Messrs. Loddiges would part with these trees, they 

 would be exactly, both as species and individuals, what would 

 suit the Boulevards. We would plant three of each species 

 adjoining each other ; and we would place a label on one of 

 them, with its name, native country, year of planting, and the 

 other usual scientific and popular particulars. The general 

 forms of these trees at all seasons; their ramifications and 

 spray in winter ; their budding, and the different tints of their 

 foliage in spring ; their different shades of green during 

 summer ; and their powerfully marked autumnal hues, would 

 delight the Parisians and spread a general taste throughout 

 France for exotic trees. There are about 150 hardy climbers, 

 exclusively of climbing roses, which might run up the stems of 

 the more hardy species ; and all those trees whose autumnal 

 tints were not conspicuously beautiful, might be enlivened by 

 the deep purple red of the Ampelopsis quinquefdlia, or the 

 claret grape. 



The success of trees planted in such a situation as that of 

 the Boulevards, the species being properly chosen, depends 

 almost entirely on the quality of the soil, its quantity, distri- 

 bution as to depth and to the supply of moisture, and more 

 especially on guarding against the evils of superincumbent 

 pressure. The last point is by far the most difficult to manage. 

 The pressure under the carriage pavement we shall not attempt 

 to get rid of; because, if the pressure on the footway be pro- 

 perly provided against, a stratum under it of proper soil, 

 3 or 4 ft. in depth, will insure the vigorous growth of the 

 trees till they attain a mature size, and strength sufficient to 

 force their roots into the surrounding strata. The modes of 

 lessening the superincumbent pressure on the soil under the 

 footway are three : — - First, by vaulting ; filling the vaults with 

 the proper soil, preserving vertical and lateral communications 

 for the introduction of water from the gutter between the path- 

 way and the roadway, and forming a footpath of gravel, or 

 other suitable material, over the vaults. Secondly, by building 

 up piers from the bottom of the stratum of prepared soil to 

 the surface, and on these piers resting flag-stones to form the 

 footpath ; provision for the entrance of water being made as 

 before, along the side next the roadway. Thirdly, by mixing 

 the prepared soil with chips of wood and fragments of com- 

 pressed manure, which will decay and leave interstices for the 

 roots ; and with gravel and the rubbish of old buildings, , in 



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