Polytechnic Association Proceedings. 915 



which we have mentioned as patented in 1836. In Usher's machine, 

 brought forward in 1849, the apparatus was propelled by a port- 

 able engine placed thereon, which also operated a rotary digging 

 device, which was also designed to "assist in the propulsion of the 

 apparatus; a rather futile idea, inasmuch as all the force exerted 

 by the digger to drive the machine was, of course, just so much 

 subtracted from its digging power. Another and more curious 

 example of this variety of tilling apparatus is found in the steam 

 tiller of Chandos Wren Hoskyiis, propounded in 1851, and in which 

 it was designed to employ rotating disks toothed at their periphe- 

 ries, so as to rasp the soil, and thus comminute the same. Notwith- 

 standing the amount of energy and ingenuity employed in adapting 

 the rotary plan to steam tilling machines, the system has fallen 

 into desuetude, and at the present time the only practically suc- 

 cessful steam-plowing mechanism in use, may be said to be that 

 operated by hauling-chains or ropes, on McRae's plan of thirty 

 years ago, the punts of McRae's system being substituted by mov- 

 able engines and pulleys arranged and anchored at opposite sides 

 of the field, either upon what is known as the direct or the round- 

 about system, most illustrations of this variety also including 

 another feature of the same invention in the double sets of plows, 

 capable of being used alternately as the machine is drawn in oppo- 

 site directions. Fowler, whose steam plows may be taken as, upon 

 the whole, the standard of success in this branch of engineering, 

 has three distinct plans, all based, however, upon the use of a 

 movable engine, and all too well and widely known to require 

 particular description here. 



Having thus briefly traced the salient features in the history of 

 steam cultivating devices in England, we may turn to the considera- 

 tion of their present efiectiveness under their most favorable aspect, 

 bearing in mind, however, that we have but glanced at the more 

 prominent features of the subject, and that the amount of ingenuity 

 developed in each of the classes we have mentioned, has been 

 something enormous — not less than three hundred English patents 

 on steam plows, steam grubbers and steam spades, having been 

 granted previous to 1859. How many more have been produced by 

 the agitation of the subject for the last nine years, the writer hsm 

 not been able to ascertain. 



In the pursuit of steam cultivation, two objects or results are 

 sought, the one purely mechanical in its nature, that of pulverizing 

 and disintegrating the soil in a superior manner; the other, purely 



