SCIENCE OF GARDENING. 



PART II. 



1 456 Garden-laddrrs are of three species. 



' The connm.ii wall-tree ladder Afters fromtliose used in other arts in having two 

 nitres of ten or twelve ind.es in length, projecting at right angles from the upper end, the 

 DM of which is to avoid injuring the trees, by keeping the top of the ladder at a small dw- 

 t nice from the wall, and thus admit of the operation of nailing, as well there as elsewhere. 



1458 The orcfiard-tiidtler consists of a frame on low wheels, as a basis for several lad- 

 dors which (it into each other, and are capable of being hoisted up by machinery so as a 

 person near the extremity of the ladder may have access to any part of a tree with con- 

 venience, 'cither to prune it or gather the fruit. 



1 459, The thr,\--styf,'d, forked, and double ladders (Jig. 206. a, b, c) are also well adaptec 

 for the ordinary purposes of gathering fruit or pruning. 



206 



1460. The rule-joint ladder (Jig- 207.) is used for working on curvilinear roofs either 

 of glass, or domes of lead, stone, &c. which require panes renewed or trees nailed. 

 Each step or foot-board, has what is called a stop, to prevent the feet from breaking the 

 glass, and at every joint is a moveable foot to project in the case of training trees on such 

 surfaces, in order that their leaves, &c. may not be injured. Such ladders are particularly 

 useful for repairing curvilinear hot-house roofs. 



207 



208 



1461. The stejy-ladder (Jig. 208.), instead of round rods on which to place the feet, has 



steps or boards, an improvement essentially necessary, where much work is to be done, 



icause less fatiguing to the feet. Such ladders have a back or fulcrum by which they 



stand independently of any other object, and which is removeable at pleasure by drawing 



