. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. part of the machine. By re-ferring to fig. 456 it will be perceived,that as each heckle bar arrives at thefront end of the guide rail g, a finger p,called a tappet or cam, on the shaft k,strikes it down to the lower guide railsh; and, in order that its descent maybe truly vertical, weighted levers q g, infront, are made to press against the faceof the heckle bar as it descends. Thisbar having now arrived at the lower guide rails h, lets fall its nibs into the grooves ofthe lower wor
. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. part of the machine. By re-ferring to fig. 456 it will be perceived,that as each heckle bar arrives at thefront end of the guide rail g, a finger p,called a tappet or cam, on the shaft k,strikes it down to the lower guide railsh; and, in order that its descent maybe truly vertical, weighted levers q g, infront, are made to press against the faceof the heckle bar as it descends. Thisbar having now arrived at the lower guide rails h, lets fall its nibs into the grooves ofthe lower worm shafts I, by whose rotation the heckle bar is made to retrogade, or re-turn towards the back of the machine. When the heckle bar has reached the hinder endof the guide rail h, a finger or tappet, r, on the lower worm-shaft, comes under it andraises the heckle bar, guided by the back-weighted levers s, as shown in fig. 456, till itis elevated to the level of the upper guide rail g; wheij the threads of the upper worm,shafts take hold of its nibs as before, and conduct it forward upon the guide rail in th«. 509 way already described. Thus the continued rotation of the worm shafts k k and I J, icauses the whole series of heckle bars to travel along the guide rails, and the tappetsp and r, by alternately depressing and raising them at the ends of the said rails, causethem to move in a regular circuit, yet so as to preserve their verticality. The claim made under this patent is for every mode in which screw or worm shaftsmay be adapted to conduct the bars carrying the needles or heckle-teeth through amachine for preparing, drawing, or roving textile fibres. In December, 1835, Messrs. Hope and Dewhurst obtained a patent for improvementsin the manufacture of flax, which deserve notice. These are of both a chemical andmechanical nature. The first consists in steeping the flax in dilute sulphuric acid, of acertain strength, and for a certain time, proportioned to the quality o
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