TRA 



TRA 



TOURMALINE, A gem, valued 

 from its inoprrty of polarizini,' li;;lit. 



TOIUlMgl'ET. A bandage uliicli 

 may be tightened to any extent by 

 means of a screw, so as to exert 

 pressure upon a cusliion, and com- 

 press the, arterial trunks to which it 

 is applied. It is chiofly used to pre- 

 vent hemorrhage in the operations of 

 amputation. 



TRACHEA. The wimlpipe. 



TRACHE.^. The spiral vessels 

 of leaves and insects. 



TRACHELIDANS. A family of 

 coleoptcra, in many of which the head 

 is supported on a kind of neck. 



TRACHEOTOMY. The operation 

 of cutting into the windpipe to ex- 

 tract foreign bodies, &c. 



TRACHYTE. An ancient lava. 



TRAGACANTH. A variety of 

 gum, which swells, but is not soluble 

 in cold water. 



TRAINEAU. A Flemish imple- 

 ment of agriculture. See Tillage. 



TRAINING. The education of 

 horses. See Horse. 



TRAINING TREES. The man- 

 agement, by pruning, of the stem and 

 branches of trees, so as to secure an 

 increase of fruit of a superior quality. 

 Training against walls has also the 

 advantage of enabling the orchardist 

 to cultivate southern fruits, and ri- 

 pen them more perfectly. The chill- 

 ing effects of winds and excessive 

 evaporation are averted, while the in- 

 creased temperature to which the 

 fruit is exposed renders it sweeter. 



There are three general plans of 



training: on espaliers, walls, or as 

 dwarf standards. The espalier is usu 

 ally a trellis, consisting of posts ten 

 feet high, set eight or twelve feet 

 apart, and sustaining horizcmtal laths 

 or wires: the trees are therefore 

 trained horizontally. This is usually 

 intended for grapes, apples, or pears. 

 But the posts arc sometimes set in 

 circles, around which three or more 

 branches are trained. This is called 

 spiral or hoop training (see Fig. 1). 

 Fig. 1. 



Funnel training is a modification . 

 the posts are set in an inclined direc- 

 tion, so as to meet at their summits, 

 and produce the outline of a cone : 

 wire is wound around it at intervals 

 of a foot. Light iron bars are some- 

 times used instead of the wooden 

 posts. 



Walls. — The choicest varieties of 

 fruit, which require additional heat, 

 are placed on walls, as apricots, nec- 

 tarines, peaches, plums, grapes, figs, 

 and some cherries and pears. The 

 method of arranging the branches dif- 



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