PRESSURE-ORGAN FAIRS,
�543
�chain guided in a pipe Fig. 380 and the spring brake Fig. 381.
The same principle is also utilised in certain machines for the
manufacture of wire- work. It is unnecessary, however, to treat
these pairs as an order (F, t ), for in all cases the flectional element
of the pair may be considered as a pressure-organ. They therefore
are all included in the order ( F, q ).
��FIG. 378.
�FIG. 379.
�Another and very remarkable pairing of Q is that with T. This
can be very easily carried out if the latter have the form T z or T r ,
if it be made, that is, as some form of chain. The "Paternoster "
pump, whether with buckets or piston discs, the grain carriers of
mills, the ladders of dredging machines, etc. all furnish illustrations
���FIG. 380.
�FIG. 381.
�of this pairing. It would be possible to indicate by a special sign
the peculiar construction of the chain, calling a tension- organ
provided with scoops T v for instance. This particularity is not
necessary, however, for if a symbol show a pairing between T z and
Q it may be held to indicate that the tension organ is arranged in
such a way that the pairing is possible. In some cases also no
special alteration of the form of the tension- organ has to be made
for this purpose, as in Vera's " rope-pump," where a mere rope
T t lifts water by adhesion.* All these pairs together form there-
- The rope-pump, or water-rope machine, has been frequently ascribed to tho
elder Brunei. It is certainly older than his time, however. See Langsdorf, ii., p. 220; Hachette, Traiti EUmentairt, p. 134. R.
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