VOL. Xm.J VHILOSOPHICAL TRANSACTIONS. 549 



Ths Description and Uses of the Steel-yard Balance Swing, invented and made 

 by Mr. Timothy Sheldrake. N" 462, p. 20. 



Where crookedness is caused by bad accidents, as falls, breaking of bones, 

 or any such causes, attended with neglect ; there it is to be feared no help can 

 be given. But where a deformity of body is owing to some defect of health, 

 ill habit of body, or some internal cause, it may be in the power of art and care 

 to prevent growing worse; or with good care and endeavours, to recover 

 entirely. For which end Mr. S. communicates this steel-yard swing, for re- 

 storing such crooked persons, whose bones are tender, and capable of having 

 their form a little altered. 



The body, being composed of bones with joints, covered with muscles, &c. 

 for moving the body, as necessity requires, so if any of these muscles that are 

 of use for bending the body forward, backward, downward, or raising it up- 

 ward, or for turning part of the body to the right or left side, have by illness, 

 or want of proper nourishment flowing so freely to one side as the other, or by 

 a careless way of sitting or lying, been contracted on one side of the body, by 

 which the bones are braced closer together than nature intended ; in this case, 

 the hip generally rises, the shoulder on the same side falls lower: the great sup- 

 port of the body, the vertebrae of the back, are altered from their natural up- 

 rightness to a curve, and the other side extended to too great a length : thus 

 the viscera are pressed too close on the contracted side, and probably hindered 

 from performing their due ofiice; while on the contrary side, which is extended 

 beyond its due bounds, there is too much room for them, that may give too 

 large a growth to them, or render them too lax and weak. From this united 

 ill state of the viscera, it is possible that crooked persons are generally un- 

 healthy. 



For removing this distorted form, and recovering a better, this steel-yard 

 swing is proposed, as a mechanical method, for stretching the contracted side, 

 and giving liberty to the too-much extended side to contract; that the sides may 

 thus be brought to their original and regular form, by suspending the crooked 

 person with cords properly covered for ease, and put under each arm, and then 

 placed at equal distances from the centre of the beam. The gravity of the body 

 will, in great probability, immediately affect the contracted side of the body, so 

 as to put the muscles a little upon the stretch ; and if the cord under the arm 

 on the longest side of the body be removed farther from the centre, the longest 

 side will become a weight continually increasing, as the point of suspension is. 

 removed farther from the point of motion ; by which means the shortest side. 



