AMERICAN INSTITUTE. 469 



The Sinking of tbe wheels in soft ground may be obviated by making 

 them sufficiently broad, as in Fawke's Engine — by getting the engine to 

 lay and take up sections of rails, upon which the wheels may roll, and 

 which, acting like snow-shoes, prevent the wheels sinking into the ground, 

 as in Boydeirs engine ; or by employing men and horses to lay movable 

 tracks for the engine to travel upon, as was actually done in England on 

 one occasion, when it was found that the laying and relaying of the movable 

 tracks cost more than the plowing would have done ; or by laying perma- 

 nent rails for the engine to travel on, either along the headlands or in par- 

 allel tracts over the field, having movable bridges from track to track. 

 These last plans, though seriously proposed, seem too cumbersome and ex- 

 pensive to need any remark ; yet Halkett's Gruideway system has met with 

 some supporters in England. 



To give the locomotive sufficient grip, when it is employed as a traction 

 engine, rails may be employed in any of the ways already indicated for the 

 adhesion of the iron wheel to an iron rail, and the friction of the one upon 

 the other is so great that, under ordinary circumstances, the wheel does not 

 slip ; or the face of the wheel may be made rough by projections upon it ; 

 all such projections, however, offer serious impediments to forward motion, 

 as the engine has to lift itself over them ; and, when on hard ground, it is 

 jarred as it passes over each. Or the face of the wheel or roller may be 

 made of a material that will adhere somewhat to the ground, and that will 

 not wear smooth. This is a neat device, and has been adopted with success 

 in the case of Fawkes' plow ; or the engine may use horse-leg pushers to 

 shove it along, as was also tried in England to effect locomotion on common 

 roads : a plan however which by no means succeeded. 



There are four ways in which a portable engine may be employed in 

 steam cultivation : 



1st. It may be constructed so light as to admit of being drawn by a team 

 over the ground while it works the soil by some suitable form of rotating 

 cultivator. For this purpose a caloric engine seems to possess many ad- 

 vantages. 



2d. It may be placed in a proper position on a field, or part of a field, 

 where it may remain stationary until such field or part has been worked, 

 its power being conveyed to the implements by means of cables, working 

 round anchored pulleys. This is the plan adopted in Smith's, or the Wol- 

 "ston system of steam plowing, which is highly spoken of in England, but is 

 decidedly too slow for American farmers. 



3d. It may warp itself from one side of the field to the other, by means 

 of a single cable and two grapnals or anchors, one at each side, while 

 it draws plows, or works a rotating cultivator or spa':]es, &c. 



Or, 4th. It may draw itself from one end of a headland to the other 

 while a truck or moving anchor passes along parallel with it on the other 

 headland, receiving its motion from the power conveyed (from the engine) 

 by an endless cable which crosses the field, and to which plows are attached, 

 SO as to be drawn backward and forward by the alternate action of the cable 



