THE FARMER'S MAGAZINE. 



233 



all the machines thrashed perfectly clean : two-thirds 

 completely avoided splitting ; and two other machines, 

 out of the nine tested, were nearly as meritorious in 

 this point. 



As regards the state of the straw, at Gloucester two- 

 thirds, and at Lincoln nnt half the machines, delivered 

 the straw whole ; and at Carlisle only two machines 

 were considered perfect in this respect; while four 

 others out of the nine nearly equalled them. But 

 breaking the straw is a fault or an advantage, accord- 

 ing to the purpose for which the straw is intended ; 

 and in districts where it cannot be sold, and is con- 

 sumed as fodder or litter for cattle (and unless it is 

 being thrashed for thatching), farmers prefer to have it 

 well broken. Altogether, the performance of the 

 strictly thrashin;? part of the machines left little to be 

 desired in regard to the quality of the work ; and in 

 two years and a-half since that time, various improve- 

 ments have been introduced. The time and power re- 

 quisite for thrashing a given quantity of corn varied 

 very much in different machines; and no doubt we 

 shall find a great advance in these particulars, when the 

 dynamometer is applied, between the engines and ma- 

 chines next July. 



The processes of extracting the grain free from straws, 

 ears, or chaff, delivering the clean straw by itself, and 

 separating the chaff and pulse, colder or cavings, arc 

 not yet conducted in the most desirable manner. At 

 Gloucester half the machines were thought to shake 

 the straw perfectly clean, and one nearly so; at Lin- 

 coln three machines performed clean shaking, and 

 seven more out of fourteen nearly equalled them ; but at 

 Carlisle there were only two out of nine machines which 

 carried absolutely no grain over with their shakers, 

 four others being only slightly defective ; while there 

 was plenty of room for improvement in the rest. So 

 far good, as respects the two " perfect " shakers ; but 

 a quarter of an hour or twenty minutes' time of work- 

 ing is not long enough to detect the liability of the 

 slats, screens, bars, or meshes of the shakers to collect 

 choking straws, and gradually impede the passage of 

 corn through them ; for what are at first considered 

 good shakers will sometimes be found to foul them- 

 selves in hour after hour of jumping underneath such 

 stuff as straw and broken cavings of all imaginable 

 lengths, bent in all possible forms, tossed in all postures, 

 and traversing across the area of the shakers in every 

 sort of direction. Freedom from liability to choke 

 is a particular, however, in which many advances have 

 lately been made. Another important consideration is, 

 that this continuous clean-shaking shall be effected 

 by simple mechanism, avoiding as far as possible all 

 shock and unsteadiness to the machine framing, and 

 excessive wear of brasses or working parts. Now, as 

 the effectiveness of the process of shaking depends upon 

 the most complete and repeated tossing or striking, 

 as well as thinly distributing, or drawing out the bulk 

 of straw, so that it may give the enclosed corn and chaff 

 every chance of dropping out, some of the most 

 thorough shakers are objectionable in their motion ; 

 while, on the other hand, some of the smoothest and 

 easiest running imperfectly perform their work. How 

 smooth and beautiful is the action of the rotary shaker, 

 which dances the straw over a succession of revolving 

 rollers armed with curved rakes or teeth ! Yet, simple 

 as are the means by which motion is communicated to 

 these rollers, how many parts and small bearings there 

 are ! and the effectiveness of the work (at any rate at 

 Carlisle) was far from perfect. But so important is the 

 steadiness which it gives, the absence of shocks, and 

 consequent smallncss of wear and repairs, and freedom 

 froin iruUing brasses and breaking shafts, that the prin- 

 Cip.c is worthy of all attempts to increase the efficiency 



of its action on the straw. Box shakers appear to be 

 the most general favourites with machine makers. The 

 original parallel-motion spars thoroughly extracted the 

 grain and chaff by their blows underneath the straw ; 

 but something more resembling a riddle or screen was 

 required to prevent straws from dropping through 

 lengthwise ; and when boxes with wire meshes or per- 

 forated sheet-iron were found to catch and block up 

 with straws, or else let them through, ingenuity devised 

 slats of various forms to let through the corn, chaff, and 

 pulse only. Then we had rocking-bars or slings at the 

 outer end, thus relieving us from one of the crank- 

 shafts, with all its wear and annoyances. However, if 

 you diminish the tossing action of the boxes at one end, 

 you must increase it at the other, either by greater 

 speed or a further rise and fall, or else keep the straw 

 longer upon the shakers in order to receive its due 

 amount of blows. This latter plan is effected by pro- 

 longing the boxes beyond the vibrating bars; but in so 

 holding back the straw, it is of course crowded closer 

 together than if it had free passage over, and this prin- 

 cipally at the point where it most of all needs opening, 

 scattering, and dancing as lightly as possible — that is, 

 just where the last few kernels are to be let fall out of 

 the whole mass of straw. As a compromise between 

 the parallel-motion, with crank-shaft at each end, and 

 the vibrating at one end and rotating at the other, 

 there is the plan of having half the boxes rock at one 

 end and half rock at the other. Four boxes are the 

 most common, but three have been tried, and we have 

 seen two worked with admirable effect, though of 

 course requiring a rapid speed. But the table shaker — 

 that is, a screen all in one piece the whole breadth of 

 t'le machine — is capable of turning out the best samples 

 of long straw and cavings, as there are no apertures (as 

 between boxes) where straws can get down, andnotliing 

 can pass except through the meshes. When con- 

 structed like a wire screen, however, straws will en- 

 tangle and collect in it ; and, if made with slats of wood 

 or hoop-iron, the weight would become an obstacle to 

 its jumping movement. The peculiar motion secured 

 by the short slings on which it swings is precisely that 

 well adapted for keeping the straw "jiightened up" and 

 loosely tossing, and as severely chucked and bounced at 

 one end or one part of the shaker ;!s it is at another. 

 Now, cannot this be retained, and yet the shaker 

 divided, so as to give a smooth and regular compen- 

 sating movement, one half rising while the other is 

 falling, and without additional slings (tiresome things) 

 or additional complication? Suppose it made in two 

 parts, not side by side, but one following the other, and 

 each extending the same breadth as at present. Retain 

 the present slings, one pair supporting the inner end of 

 the first screen or table, and the other pair supporting 

 the outer end of the second. Where the two shakers 

 meet half-way, the first is to overlap the second, and 

 both are to be hung upon cranks or eccentrics on a 

 shaft placed across underneath, as for driving box- 

 shakers. We should say that this arrangement would 

 obviate the chief objections which the table shaker is 

 now open to. 



Separating corn from the chaff and cavings as they 

 come from the thrashing machine must necessarily 

 proceed on a different principle to the shaking of the 

 straw in order to extract these products. Pulse, calder, 

 cavings, chaffings, or whatever you call the short bits 

 of straw and empty ears, can be divided from the grain 

 and chaff by screening, sifting, or straining away the 

 latter through a riddle ; but as pieces of straw can 

 penetrate endwise through an aperture large enough to 

 pass chaff and corn, the aim must be to keep them 

 horizontal, and avoid any tossing motion that might 

 turn up ears or straw into an inclined or upright posit 



