PIP 



PIP 



opening with the first warmth of the 

 spring. 



P. picea, silver fir, is a noble, upright, 

 tree ; the branches are not numerous, but 

 the bark is smooth and delicate ; the 

 upper surface of the leaves is of a fine 

 strong green, the under has two white 

 lines running lengthwise on each side of 

 the mid-rib, giving the leaves a silvery 

 look, for which reason this fir takes its 

 name; the cones are large, growing 

 erect ; when the warm weather comes on 

 they soon shed their seeds ; the scales 

 are' wide, deltoid, rounded above, below 

 beaked, and appendicled with a membra- 

 naceous, spatulate, dorsal ligule, termi- 

 nated by a recurved dagger-point ; nuts 

 rather large, membranaceous, variously 

 angular, dun-coloured. It has been ob- 

 served in Ireland, that no tree grows so 

 speedily to so large a size as the silver 

 fir; some at forty years' growth, in a 

 wet clay on a rock, measuring twelve 

 feet in circumference at the ground, and 

 seven feet and a half at five feet high; 

 one contained seventy-six feet of solid 

 timber. 



P. balsamea, balm of Gilead fir tree, 

 rises with an upright stem ; the leaves 

 are dark green on their upper surface, 

 marked with whitish lines underneath ; the 

 cones are roundish and small ; the buds 

 and leaves are remarkably fragrant ; from 

 wounds made in this tree a very fine tur- 

 pentine is obtained, which is often sold 

 For the true balm of Gilead. This tree 

 makes little progress after eight or ten 

 years' growth ; it has very much the habit 

 of the silver fir ; but the leaves are wider 

 and blunter, disposed on each side along 

 the branches like the teeth of a comb, 

 but in a double row, the upper one 

 shorter than the under ; underneath they 

 are marked with a double, glaucous line, 

 each having eight rows of white dots ; 

 they are often cloven at top. 



PIONEER, in the art of war, a la- 

 bourer employed in an army to smooth 

 the roads, pass the artillery along, and 

 dig lines and trenches, mines, and other 

 works. 



PIPE, in building, &c. a canal or con- 

 duit, for the conveyance of water and 

 other liquids. Pipes for water, water- 

 engines, are usually of lead, iron, earth, 

 or wood : the latter are usually made of 

 oak or elder. Those of iron are cast in 

 forges, their usual length is about two 

 feet and a half; several of these are com- 

 monly fastened together by means of four 

 screws at each end, with leather or old 

 hat between them, to stop the water. 



Those of earth are made by the potters ; 

 these are fitted into one another, one end 

 being alvvays made wider than the other. 

 To join them the closer, and prevent 

 their breaking, they are covered with 

 tow and pitch : their length is usually 

 about that of the iron pipes. The wooden 

 pipes are trees bored with large iron au- 

 gers, of different sizes, beginning with a 

 less, and then proceeding with a larger 

 successively ; the first being pointed, the 

 rest being formed like spoons, increasing 

 in diameter from one to six inches, or 

 more : they are fitted into the extremi- 

 ties of each other. 



Wooden pipes are bored as follows., 

 (Fig. 1, Plate Pipe-boring,) is a plan of 

 the machine ; and fig. 2, an elevation of 

 it. The piece of timber intended to form 

 the pipe is placed upon a frame, 

 a, a, a t a, and held down upon it firmly 

 by chains going over it, and round two 

 small windlasses, b b, and it is wedged up 

 to prevent its rolling sideways; if the 



Siece is tolerably straight, this will be suf- 

 cient, otherwise it must be steadied by 

 iron dogs or hooks, similar to those used 

 by sawyers, drove into the carriage at one 

 end, and into the tree at the other. The 

 frame and tree together run upon small 

 wheels traversing two long beams or 

 ground sills, D D, placed on each side of 

 a pit, dug to receive the chips made by 

 the borer ; at one end they are connected 

 by a cross beam, E, bolted upon them ; 

 this supports the bearing for a shaft, F, 

 the extremity of which, beyond the bear- 

 ing, is perforated at the end with a square 

 hole, to receive the end of the borer,/. 

 The carnage, a a, and piece of timber, 

 are advanced towards the borer by ropes ; 

 g is one hooked to it, going over a pul- 

 ley, (not seen) and returning to a wind- 

 lass, H, above the carriage, round which 

 it is coiled several times, and the end 

 made fast to it ; h is another rope, hooked 

 to it at the other end, and going over a 

 pulley, and coming to the same windlass, 

 H, it is coiled round the windlass in a 

 contrary direction to gg, and then nailed 

 fast ; by this means, when the windlass, 

 H, is turned by the handles on its wheel, 

 I, one rope will wind up, while the other 

 gives out, and draws the carriage and 

 piece of timber backwards or forwards, 

 according as the wheel is turned. The 

 weight of the borer is supported by * 

 wheel, I, turning between uprights, fixed 

 to a block, L, whose end rests upon the 

 ground sills, D ; it is moved forwards by 

 two iron bars, m m y pinned to the front 

 cross bar of the carriage, a a ; the dis- 



