The induced current from our bell when held back by 60,000 ohms of resistance in the four boys was able to push with 150 volts of pressure, and .0025 ampere passed without noticeably reducing this pressure, but when the same current was held back by only 100 ohms in the filament of the lamp nearly forty times as much current passed, and the pressure dropped to something less than ten volts. "We will try an experiment to show how the voltage will suddenly fall when we reduce the resistance of your four bodies. [Illustration: Fig. 124] "Fill these two empty tin pails in which our lunch was brought with water from the lake and sprinkle in the salt left over from the lunch. Now twist a bare copper wire around the bail of each pail and connect these with the bell so as to get the induced current from its magnet. (See Fig. 124.) Let the two pails of water be the terminals of the two wires at _S_. Now you four boys wet your hands in the water and then join hands, and those at the two ends of the line put your free hands upon the outside of the pails of water while I close the primary circuit. You of course feel the current just as you did when you held the spikes in your hands in a former experiment. But now you two end boys put your free hands into the salt water, and you instantly get a very smart shock. The resistance is no longer 60,000. It has dropped way down to 2000, and if the voltage had remained at 150 you would have received a terrible shock, but the voltage has dropped down to five. It is as though you had been pushing very hard against a post and it suddenly gave way. You cannot push against a thing which offers no resistance. So the voltage falls when resistance is reduced, and particularly if the source of supply has very little capacity. Here is another experiment you must try when you go back to the city. At a certain water faucet in my laboratory the pressure is disagreeably high. The water flows with great force and spatters badly. We can easily reduce the pressure so that the water will flow in a limpid stream. Fig. 125 shows the situation; _f_ is the faucet, and in the pipe underneath the sink there is a stop-cock _c_. This may be adjusted permanently so that the faucet _f_ will act pleasantly. The same thing is represented again at the gas stove. Let _f_ in the Fig. 125 represent a gas cock at the stove. Suppose the pressure is so high that the gas flames pass more gas than is readily consumed. It is possible to adjust a stop-cock like c further back in the pipe so as to produce hotter flames, get rid of the poisonous fumes of half burned gas, and cut down the monthly gas bills one half. [Illustration: Fig. 125]