294 GLOSSARY. 



blades twisted like a scrcAV, revolving beneath the water, the axis being 

 parallel with the keel. 



Section, one of the knives or blades on the cutter-bar of a mowing 

 maehine. 



Self-kakek, a contrivance attached to a reaping machine, to throw 

 off the cut grain in gavels, to obviate raking off by hand. 



Shears, or Sheers, two poles lashed together like the letter X, for 

 placing under heavy poles, etc., in raising them ; also to single vertical 

 poles supporting pulleys, for a similar purpose. 



Sheave, the wheel of a pulley set in a block. 



Shoot, or Shute, a passage-way down which grain, hay, or straw, is 

 slid or thrown. 



Side-draught, the side pressure of a machine on the team which 

 draws it, as distinguished from centre draught. 



Single-tree, a single whiffle-tree, the cross-bar to which the traces of 

 a horse are attached, as distinguished from a doubletree, or two-horse 

 whiffle-tree. 



Siphon, or Svphon, a bent tube for drawing off liquids; the column 

 of liquid in the outer or longer leg overbalancing the iuner column, 

 and producing a current. 



Skein, the iron casing of a wagon-axle on which the wheel runs. 



Skim-coulter, a coulter of a plow so constructed as to pare the sur- 

 face before the mould-board. 



Skim-plow, the small forward mould-board, of a double Michigan or 

 Sod-and-subsoil plow. 



Slide-rest, the rest or support of the chisel in a turning lathe, made 

 to slide along the frame for cutting successively the different parts of the 

 work. 



Slot, a slit or oblong aperture in any part of a machine, to admit an- 

 other part. 



Snath, the handle or bar to which the blade of a scythe is attached. 



Sod, the slice of earth cut by the passing of a plow. 



Sole, the bottom plate under a horse-shoe tile, in draining. 



Spindle, a small axle in machinery, as distinguished from a shaft or 

 large axle. 



Spirit-level, a glass tube containing alcohol with an air-bubble, her- 

 metically sealed at both ends, the position of the bubble at the middle 

 sliowing the tube to be level. 



Spur-wheel, or pinion, a cog-wheel Avith teeth parallel to the axle. 



Standard, an upright supporting timber; the front upright bar in a 

 plow to which the mould-board is fastened. 



Steam chest, a box attached to the cylinder of a steam-engine, in 

 which the sliding valves work. 



Stirrup, an iron band encasing a wooden bar, for attaching to some 

 other part. 



Stud, a short, sto it support. 



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