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keeps them down by the forefinger of the left hand,whilst he presses the forefinger of the right handgently against their ends: those which have thepoints towards the right hand stick into the finger-stall ; and the child, removing the finger of theleft hand, slightly raises the needles sticking into thecloth, and then pushes them towards the left side.Those needles which had their eyes on the righthand do not stick into the finger cover, and arepushed to the heap on the right side previouslyto the repetition of this process. By means of thissimple contrivance each movement of the finger,from one side to the other, carries five or six needlesto their proper heap ; whereas, in the former method,frequently only one was moved, and rarely morethan two or three were transported at one movementto their place.
(12.) Various operations occur in the arts in whichthe assistance of an additional hand would be a greatconvenience to the workman, and in these cases toolsor machines of the simplest structure come to ouraid : vices of different forms, in which the materialto be wrought is firmly grasped by screws, are ofthis kind, and are used in almost every workshop ;but a more striking example may be found in thetrade of the nail-maker.
Some kinds of nails, such as those used fordefending the soles of coarse shoes, called hobnails,require a particular form of the head, which is madeby the stroke of a die. The workman holds the red-hot rod of iron out of which he forms them in his lefthand; with his right hand he hammers the end of itinto a point, and cutting the proper length almost off,