In a recent modification called ‘ The Intensive Break’ very  heavy currents, quoted as 25 amperes at 110 volts, may be  passed through such a break if desirable. This is a decided  advantage, though the price is somewhat higher than for the  ordinary form.

A recent London make (illustrated in Fig. 34) is driven  by a star-shaped magnet of soft iron, which is mounted on  the upper end of the jot shaft. This is rotated by influence  of the successive magnetisations and demagnetisations of the  core of the induction-coil, opposite the end of which the in-  strument is set. In this break the jet-producing portion is  enclosed in an air-tight metal reservoir filled with coal-gas or  hydrogen, which acts as a dielectric to cover the points of  contact instead of the usual liquid. This avoids the forma-  tion of sludge, and consequent inconvenience of frequent  cleaning. The speed may be regulated somewhat by altering  the position of the interrupter relative to the coil, thus re-  quiring no special rheostat; but this regulation of speed is  not thoroughly satisfactory. The break is quiet in action,  even with heavy currents, is of comparatively moderate price,  and we reckon it one of the best turbine breaks on the  market.

To avoid the starting by hand, which necessity may be  somewhat inconvenient, the makers also supply a small  independent coil, by which the break may be driven and  continue in rotation whether the larger coil be in or out  of circuit.

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