AMERICAN INSTITUTE. 



137 



These joints often perform many months without need of lubrication, or other 

 attention, a desideratum fully appreciated by the wearer. 



The tendo achillis, or heel ten- 

 don F, perfectly imitates the natu- 

 ral one in use. It is attached to 

 the bridge G, in the thigh, and 

 passing down on the back side of 

 the knee-bolt E, is firmly fastened 

 to the heel. It acts through the 

 knee-bolt, on a centre, when the 

 weight is on the leg, imparting 

 security and firmness to the knee 

 and ankle joints, thus obviating 

 all necessity for knee-catches. 

 When the knee bends in taking a 

 step, this tendon vibrates from the 

 knee-bolt to the back side of the 

 thigh A, figure 2. It descends 

 through the leg, so as to allow the 

 foot to rise above all obstructions, 

 in flexion, and carries the foot 

 down again, in extension of the 

 leg for the next step, so as to take 

 a firm srpport on. the ball of the 

 , foot. Nature-like elasticity is thus 

 attained, and all thumping sounds 

 are avoided. 



Another tendon II, of great 

 strength and slight elasticity, ar- 

 rests the motion of the knee gent- 

 Internal view semi-flexed. ly, in walking, thus preventing all 

 disagreeable sound and jarring sensation, and giving requisite elasticity to the 

 knee. 



A spring, of metal or other material, as rubber, &c., lever, and tendon I J K, 

 combining with the knee-bolt, give instant extension to the leg, when it has been 

 semi-flexed to take a step, and admit of perfect flexion in sitting. 



A spring and tendons in the foot L M N, impart proper and reliable action to 

 the ankle-joint and toes. The sole of the foot is made soft to insure lightness and 

 elasticity of step, and accommodate any surface. 



The stump receives no weight on the end, and is well covered and protected, to 

 avoid friction and excoriation. These joints, springs, and tendons are all pate7ited. 

 Fig. 3, is an external view of Palmer's perfect model. (A gold medal having 

 been before awarded.) [Diploma. 



Bartlett^s Patent Ventilating Polar Refrigerator. 



Bartlett & Lesley, 426 Broadway, N. Y. 



This refrigerator is constructed upon scientific principles. The ice receptacle is 

 made in a wedge form of corrugated zinc; and it is placed in the middle of the box, 

 and forms two separate and distinct provision chambers; either one of them, it is 

 claimed, is as eifcctive and convenient as the whole of any other in use. The ice 

 is placed in the upper section of this receptacle upon a strong rack; immediately 



