The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . he Norwegianharrow with its revolving rows of spikes. A few variations and developments of the ordinary harrow requirenotice. In the adjustable harrow (fig. 2) the teeth are secured tobars pivoted at their ends in the side bars of the frame, and providedwith crank arms connected to a common link bar, which may bemoved horizontally by meant of a lever for the purpose of adjusting In Mid. Eng harwe; the O. Eng appears to have been liearge; theword is cognate with the Dutch hark. Swcd. harke, Ger. If
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . he Norwegianharrow with its revolving rows of spikes. A few variations and developments of the ordinary harrow requirenotice. In the adjustable harrow (fig. 2) the teeth are secured tobars pivoted at their ends in the side bars of the frame, and providedwith crank arms connected to a common link bar, which may bemoved horizontally by meant of a lever for the purpose of adjusting In Mid. Eng harwe; the O. Eng appears to have been liearge; theword is cognate with the Dutch hark. Swcd. harke, Ger. Ifarke, rake,and with Danish harv, and Swcd. harf. harrow, but the ultimateorigin is unknown: the Fr. herte is a different word, cf. Hearse. HARROWBY—HARROWING OF HELL the angle which the teeth make with the ground, and thus convertthe machine from a pulverizer to a smoothing harrow. The smallfigure illustrates a spring connexion between the adjusting lever andits locking bar, which allows the teeth to yield upon striking anobstruction. As the briskness of the operation adds to its effective-. FlG. 2.—Adjustable Harrow. ness, the harrow is often made with a seat from which the operatorcan hasten the team without fatiguing himself. Fig. 3 illustrates a spring-tooth harrow. In this harrow the in-dependent frames are carried upon wheels, and a seat for the operatoris mounted upon standards supported by the two frames. The teethconsist of flat steel springs of scroll form, which yield to rigid obstruc-tions and are mounted on rock shafts in the same manner as in thewalking harrow before described. The levers enable the operator toraise the teeth more or less, and thus free them from rubbish andalso regulate the depth of action. Another variation of the harrow with great pulverizing andloosening capabilities consists of a main frame, having a pole andwhipple-trees attached; to this frame are pivoted two supplementalframes, each of which has mounted on it a shaft carrying a series
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
