The use and Operation of the Aforementioned Apparatus

Abstract

There should always be some water in the lower receptacle up to point, st. Then both vessels should be evacuated by means of a copper sphere (as illustrated in Plate VIII, figure 3) whose capacity is essentially the same as that of the two receivers. This sphere should be evacuated and inserted into the stop-cock, f, and in this way the air contained in the receptacles will enter into the sphere. This process should be repeated several times until almost all air is extracted (a state that can be recognized when little air or none at all rises out of the water from the upper glass through the middle tube, r. Then one should close the stop-cocks, d and f, simultaneously; the other two stop-cocks, however, which have pointed tubes, should be opened a little (if there are three or four of these, so much the better). Then one will see and hear at the same time air breaking through the water with a hissing sound, more or less loud according to the position of the stop-cock keys. This can continue day and night for one, two, or three weeks and can serve as a way to pass one’s time. One should bear in mind, before all else, however, that the danger of air’s seeping in unnoticed should be prevented: and that if pins are inserted in the mouths of the tubes a more pleasant sound can be produced. For the smaller these holes are, the more the air is constricted and is forced to hiss.