The operator, whose attention is thus attracted, inserts a peg in the jack, then throws over the speaking key of the cord circuit, and having ascertained particulars of the requirement places the other peg of the pair in the nearest multiple jack of the wanted subscriber, whom she proceeds to ring up. In the meantime the callinglamp has darkened; and each subscriber's line being equipped with a cut-off relay whose function it is to disconnect tl, e calling apparatus while the circuit is in use, the insertion o r a peg is immediately followed by the disappearance of the calling signal.
This high mean pressure cannot be maintained for long, because as the speed increases the demand for steam per unit of time increases, so that cut-off must take place earlier and earlier in the stroke, the limiting steady speed being attained when the rate at which steam is supplied to the cylinders is adjusted by the cut-off to be equal to the maximum rate at which the boiler can produce steam, which depends upon the maximum rate at which coal can be burnt per square foot of grate.
By way of the White river cut-off the Arkansas finds an additional outlet through the valley of that river in times of high water, and the White, when the current in its natural channel is deadened by the backwaters of the Mississippi, finds an outlet by the same cut-off through the valley of the Arkansas.
The subscriber's meter is joined in multiple with the cut-off relay, and whenever a peg is connected to the circuit a current flows through the meter.
A 4-lb weight lodges the detent of the cut-off slide: The slide springs forward and cuts off the flow.
His eyes were dancing with amusement as he used one hand to jerk the towel free and expose cut-off blue jeans.