The simplest type of this mechanism is the postman's hand (Figs. 165 and 166).
Figs. 165 and 166. Postman's hand.
The left hand of the postman who sorts letters has for its work to keep in the proper order the envelopes which are arranged in little packets; the right hand has only to push the letter into place between a flat spring, fixed to the wrist, and the back of the hook. If two or three springs are supplied the postman can arrange two or three packets of letters at the same time. He can also bind the packet with string.
The vine-dresser's hand is provided with this spring to hold small flat objects, but the second spring is wavy in outline, so that semilunar spaces are left between it and the first. Into these branches slip when the spring is pressed against them, and they are thus held more firmly, whilst being sawn or pruned, than by the twisting action of the old pattern hook of Gripouilleau (Figs. 167 and 168).
Fig. 167.—Horticulturist's hand.
Fig. 168.—Method of holding a branch.
This thrust to seize the branch is somewhat rough, and is only possible in holding hard wood which there is no fear of bruising. For more delicate shoots (grafting vines indoors, preparation of cuttings), a grip is necessary which can be opened before seizing hold of the object. This is accomplished by prolonging the spring towards the forearm as a handle, pressure upon which against the chest (when standing), or against the knee (when sitting), opens the grip, in which the graft, for example, is then placed in the opening of the correct size.