Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . Pea and Pencil Case. retracted into its sheath to reduce the lengthof the instrument and preserve the lead frombreakage when carried in the 3621. The usual form has a hollow hold-er from which the tube holding thepencil-lead is projected by twistingor by simply .sliding out. In Fig. 3620, the ea.*e cousisb? of a singletube with a screw cap. and a rev
Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . Pea and Pencil Case. retracted into its sheath to reduce the lengthof the instrument and preserve the lead frombreakage when carried in the 3621. The usual form has a hollow hold-er from which the tube holding thepencil-lead is projected by twistingor by simply .sliding out. In Fig. 3620, the ea.*e cousisb? of a singletube with a screw cap. and a reversible pen-holder and pencil-point. The tube has alsoa st^-tion extensible telescopically. In Fig. 3619. the peo is on a sliding pieceat one eud, while the pencil-holder is sock-eted in the other end, cither projecting foruse or inclosed for compactness in carrying-ing. The ever-point pencil was patent-ed in England in 1823 by Hawkinsand Mordan. The small of black-lead is pushedforward by a driver, so J*s to project throughthe end of the nozzle. On the out.^ide of thedriver is a screw, and on the end of theiMd-cylinder is a nut, so that when the noz-zle is held in one hand while the case isturned by the other, the dr
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Keywords: ., bookcentury1800, booksubjectin, booksubjectmechanicalengineering
