82 ANNUAL OF SCIENTIFIC DISCOVERY. 



and loops at suitable distances along its length, so that the sail is prevented 

 from slatting, while at the same time it is at perfect liberty to be extended 

 or contracted by suitable cords. The main shaft of the mill is hollow, 

 and through it leads a light shaft, which carries on its end, and in front of 

 the centre of the wind-mill, a bevel wheel. This wheel gears into power 

 wheels keyed on the end of light shafts which extend the whole length of 

 each arm, having bearings at proper intervals along its length. Revolv- 

 ing these shafts in one direction, contracts the sail by shortening a set of 

 cords leading directly to t- 3 leech or edge of the sails, while revolving 

 them in the other directi n releases these cords and contracts another set, 

 which are rove through sheaves or through staples on the opposite side, 

 and serve to extend the sail. When all is right, the small shaft in the 

 centre of the main driving shaft is allowed to turn with it ; but if the wind 

 freshens and the mill moves too fast, the small shaft must be retarded, 

 which will have the effect, by revolving the bevel wheels, to reef or con- 

 tract the sails. As the weather moderates, and more sail becomes desira- 

 ble, the surface may be extended by giving the regulating or central shaft 

 a greater velocity. 



This arrangement is easily adapted to employment with a governor, so 

 as to be literally self-adjusting, and in any event will, if successful in. 

 practice, save much of the most disagreeable labor in attending wind-mills 

 that of reefing in cold and wet weather. A forty horse-power mill, or 

 one the sails of which are each thirty-three feet long and six feet wide, 

 would probably require considerable power to extend the sails thus simul- 

 taneously ; but it may be recollected that this operation will usually be 

 performed when the wind ia light, the action in reefing being merely that 

 of a brake to retard the wheel, and the action of the cords on the sails is, 

 in this case, direct. Mr. Vice has provided means for making the mill 

 itself supply the power for this purpose, and considers the whole suscep- 

 tible of complete control by an ordinary governor. 



An improvement in wind-mills has also been made by Daniel Halladay, 

 of Ellington, Connecticut. This consists of the attachment of wings or 

 sails to rotary movable spindles furnished with levers. These levers are 

 also attached to a head which rotates with the sails upon the same shaft. 

 Another lever is attached to the head. This is connected to a governor, 

 which slides the head upon the shaft, so as to cause the levers to turn the 

 wings or sails. The necessary resisting surface being thus presented to 

 the wind, a uniformity of velocity is attained. The proper regulation of 

 the obliquity of the sails, so as to adapt them to the varying motive force 

 of the atmosphere, is represented by the inventor to be thus secured, 

 without difficulty, to a degree which renders his mill more constantly 

 available than those hitherto employed. The mill built by him has five 

 feet wings ; that is, the diameter of the wind wheel is ten feet ; and it has 

 been in operation for six months, without a hand being touched to it to 

 regulate the sails. It is so contrived that nothing but a squall of great 

 severity falling upon it without a moment's warning can produce damage. 



