THE FARMER'S MAGAZINE. 



143 



The main platform is constructed of timber framing, 

 and in cross-section is exactly like a trussed roof, witli 

 the tie-beam, rafters, king post, or tie-rod, and struts, or 

 braces. The tie beams or cross beams are not solid, 

 but are made of two bosrds or planka placed on edge, and 

 secured together by blocks or cross pieces ; a horizontal 

 board is placed at the lower part to resist the lateral 

 strain to which the girders or beams are subjected. By 

 this arrangement the necessary strength is ensured, with 

 considerable lightness of material. We conceive that 

 the hollow wrought-iron girder system could be adapted 

 with success to the construction of a platform of wider 

 space than any yet contemplated by Mr. Halkett. There 

 is no engineering difficulty in the way to prevent a space 

 of much above fifty feet being obtained. Bythejudi- 

 cious use of wrought-iron a platform of great space, 

 with all the rigidity retiuired and of grreat lightness, 

 could be constructed. But to return : The whole of 

 the cross girders or tie beams are secured together by 

 transverse bearers, which run in a direction parallel to 

 the rails, and are further strengthened by light wrought- 

 iron diagonal tie rods or stays, which stretch from corner 

 to corner of the under side of the platform. The ends of 

 the planks forming the sides of the girders or main tie- 

 beams of the platform are secured to vertical uprights, 

 which afford bearings for the running or drivinfj wheels 

 already alluded to. The bearings of these wheels are not 

 fixed to those uprights, but are allowed to slide freely up 

 and down in guides formed between the sides of the up- 

 rights ; at the upper part of these guides strong springs, 

 all of equal strength, are placed, to offer resistance to 

 the bearing of the wheels when having a tendency to 

 move too far upwards. By this arrangement the whole 

 weight of the platform is transferred to these wheels 

 through the medium of the springs. As before stated, 

 these springs must be all of equal strength, so that each 

 wheel may bear as nearly as possible the same amount 

 of weight while resting on a level surface, and they 

 must also possess a considerable amount of elas- 

 ticity, to enable the several wheels to pass over any un- 

 dulations of the rails without transferring too much 

 weight from some of the wheels to the others. A main- 

 tenance of a uniform distribution of the whole weight of 

 the platform on the wheels is what is aimed at in this 

 arrangement. 



At each end of the platform a steam-engine is placed : 

 by preference the patentee employs the portable form, 

 as engines of this class can be easily removed from 

 one platform to another, and used for other purposes, 

 as for thrashing, &c. The two engines are coupled to- 

 gether, the cranks of the main driving shafts being at 

 right angles to each other ; so that while one is at its 

 dead points, the other shall be receiving the full im- 

 pulse of the engine. The cranks are not on the same 

 shaft, but are connected together by wheel gearing, and 

 by a transverse or cross shaft, which stretches from one 

 side of the platform to the other, and is supported on 

 suitable bearings, bolted to the platform. To each end 

 of this shaft a spur wheel is provided, gearing with a 

 spur wheel of equal size, keyed on to the end of the 

 crank shaft of the engine. The speed of the cross shaft 

 is thus equal to that of the engine shaft. To reduce 

 the speed of the cross shaft change wheels are used ; the 

 spur wheel on the cross shaft being thrown out of gear 

 with the spur wheel on the crank shaft of the engine by 

 means of a sliding clutch ; another spur wheel on the 

 cross shaft being at the same time thrown into gear with 

 a pinion, or wheel of less diameter, fixed on the crank 

 shaft of the steam-engine. The two engines are thus 

 coupled together, and the motion of both so regulated 

 that one side of the platform cannot advance quicker 

 than the other. 



To the outer extremities of the axles of the 

 driving wheels, on which the platform rests, small cranks 



are keyed on, and which have a limited motion up and 

 down, along with the bearings which have already been 

 described. The crank pins of these cranks take into, 

 or play in vertical slots, made in a horizontal, light, open 

 framework, serving as a connecting-rod to connect all the 

 cranks together. The extremities of these frameworks 

 or connecting-rods are jointed to the crank pins of 

 cranks, the shafts of which are supported in suitable 

 bearings at the end of the timbers or planks of the plat- 

 form. To the same crank pins the extremities of 

 four connecting-rods — two at each end of the platform 

 — are jointed ; these are carried diagonally upwards, 

 and jointed at their upper extremities to the crank pins 

 of cranks which are keyed on at right angles to theenJs 

 of the cross shaft; which receives its motion from the 

 engine in the manner already described. 



Each wheel is thus made a driving-wheel, being acted 

 on directly by the horizontal frame or connecting-rod, 

 which receives its motion from the engine through the 

 medium of the two connecting-rods, one at each end, 

 jointed at their upper ends to the crank pins of the cranks 

 on the cross shaft. The bite on the rails obtained by this 

 arrangement is such that the engine can propel the plat- 

 form up inclines of 1 in 15 with comparative ease, and 

 without any momentum. Such is a brief outline of the 

 peculiarities of construction of the mechanism of the 

 new system — we now enter on the consideration of the 

 second head, " practice." 



And, first, as to ploughing. The method by which 

 the ploughs are raised and lowered, that is, put in and 

 taken of work according to the direction in which the 

 main platform may be proceeding, is very simple. Each 

 plough body is attached to the end of a long lever, the 

 opposite end of which is jointed to the end of a bolt, 

 firmly connected with the main platform. These points 

 of suspension are capable of adjustment at any point of 

 the platform. To the end of the lever, at which the 

 plough body is attached, a curved guide is fixed ] in the 

 inner side of this bar, and towards its upper extremity 

 several teeth are provided ; the bar, in fact, forms a 

 curved rack, the teeth of which enter into those of a 

 small pinion, the axis of which revolves in bearings 

 placed on the upper side of the main platform. As the 

 rack is raised by the revolution of this pinion, the end 

 of the lever, to which the lower or opposite end of the 

 rack is fixed, is raised also, and with it the plough body, 

 which it carries. A series of levers, with tlieir racks, 

 are placed parallel to one another, and to the rails on 

 which the platform traverses. The levers bearing the 

 corresponding set of ploughs, with their mould-boards 

 pointing in an opposite direction to the mould-boards 

 of the other set, are swung the opposite way ; so that 

 the curved racks of each set of plough levers are at op- 

 posite sides of the platform. When arranged for plough- 

 ing, one set of curved racks are depressed to their lowest 

 point, the ploughs being in [contact with the soil ; the 

 other set being raised to their highest elevation, the 

 ploughs being suspended in the air. The pinions which 

 gear into the segmental racks that raise or depress the 

 plough bodies are keyed on to two shafts, which stretch 

 across the full breadth of the platform, and revolve 

 in suitable bearings. To the ends of the shafts cross 

 handles are fixed, by means of which the attendants on 

 the platform can work the pinions, raising or depressing 

 the plough as required. 



In ploughing by the implements as thus arranged and 

 under control, Mr. Ilalket states that there is no prac- 

 tical limit to the depth of soil inverted. Neither, from 

 the peculiar nature of the plough body used, is the hard 

 crust or sole — inherent in the action of the ordinary 

 plough — obtained. By his method of operation he suc- 

 ceeds in getting a stirred soil to the depth of twenty- 

 five inches. On this point, he says : " I have first 

 drawn six ploughs, cutting six furrows simultaneously 



