I. I have frequently found that when the raps were feeble or interspersed, an excellent way of producing them was to form a chain of the sitters’ hands round the table. One of the sitters, without breaking the chain—which he avoids doing by taking in the same hand his neighbours’ right and left hands—makes, with his freed hand, circular sweeps or passes a little distance above the circle formed by the sitters’ outstretched hands. Having done this, the experimenter draws his hand towards the centre of the circle to a variable height, and makes a slight, downward movement with his hand; then he abruptly arrests the movement at about five or six inches away from the table, when a rap invariably follows, corresponding with the sudden cessation of the movement. It is exceptional when this process does not give a rap as soon as there is a medium in the circle who is capable, in however feeble a degree, of producing raps. The same experiment can be made without touching the table, _i.e._ by forming the chain above the table. One of the sitters then experiments as in the preceding case. This is not the only observation I have made. I have noticed that with mediums of decided power, it was unnecessary to adopt any special method for the production of raps, as they were forthcoming as soon as any sort of movement with hands or feet was executed. With strong mediums, it often suffices to move the hand above the table, to shake the fingers, to gently press the foot upon the ground, in order to determine the production of a rap. Needless to say with some mediums raps are forthcoming without the execution of any movement whatsoever: with patience nearly all physical mediums can obtain raps without movement. But it seems as though the execution of a movement acted in the nature of a determining cause: the accumulated energy then receives a sort of stimulus, the equilibrium is disturbed by the addition of the excess energy unemployed in the movement, and a kind of explosive discharge of neuric force occurs, causing the phenomenon of raps. This is, however, only a working hypothesis.