98 



MEcnA]sncs. 



Fii?. 106. 



m0 



forward pair, by connecting the end of the chain at the 

 same time to the plow. 



wier's sixgle-tree. 



This is used exclusively for plowing in orchards, and is 

 worthy of notice here. The leather traces are hooked at 



the rear of the wooden 

 bar, and, passing around 

 the ends, prevent the 

 possibility of being 

 caught in the bark of the 

 trees. The teamster may 

 therefore drive as closely as he chooses without danger of 

 injury. For this reason he is able to turn over the whole 

 surface without leaving an unplowed strip along the row. 



CONSTRUCTION AND USE OF THE DYNAM03IETER. 



The dynamometer, or force-measurer, has been already 

 briefly alluded to, but a more particular description will 

 be useful. In the construction and selection of all ma- 

 chines and implements that require much power in their 

 use, the dynamometer is indispensable, although at present 

 but little known. As an example of its utility, the farmer 

 may wish to choose between two plows whicli, so far as 

 he can perceive, may do their Avork equally well ; but 

 this instrument, when applied, may show that the team 



