WINDING-MACHINE. 



turned round every time, fo as to draw the barrel round in 

 one direftion the firfl time, and in a reverfe direftion the 

 next time. The horfe turns at the fame time that the 

 bafliets are unhooked and changed at the top and bottom 

 of the pit, and very httle time is loft. A boy is required to 

 lead and direft the horfe. In fome large horfe-machines 

 wheel-work is. introduced, to communicate the motion of 

 the vertical axis of the horfe -levers to the barrel on which 

 the rope winds ; and this work may be fo contrived as to re- 

 verfe the motion of the barrel at pleafure, although the 

 horfes always walk in the fame direftion. 



In very deep pits an inconvenience is experienced from 

 the weight of the great length of rope which muft be em- 

 ployed ; for the whole weight of this rope is added to the 

 weight of the loaded corve when it is at the bottom of the 

 pit ; and at the fame time, the other corve being at the top 

 of the pit, there is no length of rope on that fide to counter- 

 balance. As the corve is drawn up from the bottom, the 

 other defcends into the pit ; this (hortens the length of the 

 afcending rope, and increafes the defcending rope, fo that 

 by the time that the corve is half drawn up, the other is let 

 half down, and the weight of the rope is equally divided, fo as 

 to be in balance ; but after this, the defcending rope becomes 

 the longeft, and its weight tends to weigh up the loaded 

 corve, and in very deep pits, the weight of the rope ex- 

 ceeds that of the corve fo as to draw it up : hence, there 

 is a great inequality in the force required to turn the 

 machine. To remedy this, the barrel is often made of a 

 conical fhape, being fmalleft in the middle, and larger to- 

 wards the upper and lower ends ; the ends of the two ropes 

 are made fail to it in the middle, or at the fmalleft. part, and 

 therefore the horfe has greater power when the corve is to 

 be drawn from the bottom, and all the length of rope is 

 added to its weight, becaufe the rope winds on a fmaller 

 radius ; but as the rope coils on the barrel, it winds on a 

 larger part of the cone, and the power or leverage diminifhes ; 

 therefore, the horfe will draw up the corve with a rapidity 

 which increafes in proportion to the diminution of the load, 

 by the fhortening of the rope. 



A very convenient mode of conftrufting a double conical 

 barrel is to fix two circular wheels upon the axis, one for the 

 top of the barrel, and the other for the bottom of the 

 fame. Two old cart-wheels are frequently employed for 

 this purpofe. The barrel on which the rope is wound is 

 formed by a number of ftraight pieces of wood, which are 

 fixed to the rims of the wheel, and extend from the upper 

 to the lower one. Thefe pieces arc not fixed in a direftion 

 parallel to the vertical axis of the barrel, but are fixed crofs- 

 wife in an oblique direftion, and thus form a barrel, which 

 is fmall in the middle, and larger at the ends. When a cy- 

 lindrical drum is fixed upon the main ftiaft to wind up the 

 rope, if the pit is deep, a counterbalance to the weight 

 of the rope muft be appHed to a fmaller conical drum fixed 

 on the vertical axis above the great drum. The circumfer- 

 ence of the conical barrel is grooved with a fpiral groove, 

 like the fiifee of a watch ; upon this fufee a rope is applied, 

 which defcends into a fmall pit made on purpofe, and has a 

 counter-weight at the end of it : this balances the unequal 

 weight of the great rope, if the rapidity of the cone is pro- 

 perly proportioned. Tiiis anfwers very well for fmall depths ; 

 but for a deep pit, the fufee muft be placed on a feparate 

 barrel. This barrel may be placed horizontally over the pit 

 in which thebalance-wi-ightdeicends, and muft have a wheel 

 upon it to communicate by a rope with a wheel fixed upon 

 the vertical axis of the gin ; by this means, the fame motion 

 is communicated to a fpiral, as if it was placed immediately 

 on the vertical axis. 



A perfeft equal motion is not neceftary for horfe-work, 

 and if it is not fo much in extremes as to ftrain the horfe in 

 one part of his journey, whilft he has nothing to do in an- 

 other, he will work very well. Gentle afcents and defcents 

 in a road are found as advantageous to the aftion of horfes 

 as a road upon a perfeft flat. The following is the conftruc- 

 tion recommended by Mr. Smeaton for a two-horfe gin for 

 a lead-mine : — The horfe-track 36 feet diameter, and two 

 horfes are employed at once ; the diameter of the drum 

 14 feet ; the weight to be drawn at once 5^ cwt. or 644 lbs. 

 exclufive of the bucket, becaufe there are two, and the one ' 

 ferves as a balance for the other ; depth of the pit 45 fathom, 

 or 270 feet ; the girt of the rope 6^ inches. The counter- 

 balance for the unequal weight of the great rope is con- 

 ftrufted as follows : — Above the drum or rope-wheel,a fmaller 

 one, or balance-drum of one-fourth the diameter of the» 

 great drum, or 3 feet 6 inches, muft be firmly fixed to the 

 upright axis ; alfo a httle ftiaft or pit muft be funk at a con- 

 venient diftance from, the machine : if this is oppofite the 

 great pit, it will require lefs bracing to keep the fixed parts 

 of the framing at their proper diftances. A hole muft be 

 made in the circumference of the fmall wheel, or balance- 

 drum, through which the end of a rope is pafted, and fe- 

 cured by a knot. This rope, which is for the counter- 

 weight, is to pafs over a pulley of 3 feet or more diameter, 

 fuch as is ufed to direft the great ropes down the main ftiaft ; 

 but it muft be ftrongly and fubftantially fixed, becaufe there 

 will be a greater ftrain upon it. Over this pulley the ba- 

 lance-rope goes down into a little pit funk for the purpofe, 

 and a balance-weight is hung to it, which muft be double 

 the weight of 45 fathom of the main pit-rope, and it will 

 aft as a counter- weight to the great pit-rope. The counter- 

 weight muft not, however, go down fo as to touch the bot- 

 tom of the little pit ; and it muft be fo regulated as to be 

 at the loweft point when the two buckets are at their meet- 

 ings, half way down the main pit. Hence, whichever way 

 the main drum turns round, the counter-weight will be 

 drawn up, and will arrive at the top when either of the 

 buckets arrive there : by this means, whatever be the weight 

 of the rope, though it exceeds the weight of matter in the 

 bucket, yet the horfe will always have fomething to draw ; 

 whereas in the old horfe-gins made at Newcaftle, they had 

 no other metliod than turning the horfes at the point of equi- 

 librium ; and after that letting them draw the backward 

 way, which obliged them alfo to walk backwards, till 

 the bucket arrived at the top. 



As a 6i-inchrope is far more than equivalent to the weight 

 required to be drawn, the fame fort of rope will do for the 

 counter-weight alfo ; but as there will be a great deal of 

 chafing at the hole where it is fixed to the little drum-wheel, 

 in confequence of its bending alternately one way and then 

 the other, it will be proper to fortify it there with the white 

 leather made of horfes' fliins, and the hole itfelf ftiould be 

 rounded off on each fide, f» as to make the rope bend eafily. 

 In the finking of the little ftiaft, if there is any particu- 

 lar advantage or obftacle, the depth may be greater or lefs 

 than a quarter part of the main fhaft ; but then the fize of 

 the little drum and counter-weight muft be proportioned 

 accordingly. If prafticable, the pit had better be deeper ; 

 and if it was half the depth, then the little drum might be 

 half the diameter of the large one, and the counter-weight 

 would be no more than the weight of the rope in the great 

 pit. On account of the expence of the balance-pit, the 

 double conical drum, which requires no counter-weight, is 

 much preferable to any machine with a counter-weight. 



In our article Water we have ^ven the experiments on 

 the ftrength of horfes ; from which it appears that a proper 



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