. Thinking, feeling, doing . Fig. 59. An Experiment in Tickling. sure ; that is, it need not be perfectly regular. If any ob- , such as a feather or the finger, be held lightly Jot^e regular-against the face, a tickle is felt, due to the trembling ofthe hand. The tickling thing need not stay at one spot, but may or at the samebe moved along continuously. A feather drawn over spotthe temples makes a strong tickle. A fly walking over io6 Thinking, Feeling, Doing. Change ofpressure. Experiment. the skin produces an unbearable tickle in exactly thesame way. Stories of the Thirty Years
. Thinking, feeling, doing . Fig. 59. An Experiment in Tickling. sure ; that is, it need not be perfectly regular. If any ob- , such as a feather or the finger, be held lightly Jot^e regular-against the face, a tickle is felt, due to the trembling ofthe hand. The tickling thing need not stay at one spot, but may or at the samebe moved along continuously. A feather drawn over spotthe temples makes a strong tickle. A fly walking over io6 Thinking, Feeling, Doing. Change ofpressure. Experiment. the skin produces an unbearable tickle in exactly thesame way. Stories of the Thirty Years War relate howthe soldier-robbers forced the peasant to reveal his treas-ure by subjecting him to unbearable tickle. When a pressure is already felt, it can be madestronger or weaker to a certain degree before the changeis perceived. The experiment can be made with a pair of beam-balances. The hand, supported by a block or cushion,. Fig. 60. Finding the Least Noticeable Change in Pressure. is placed under the scale-pan so that when the scale isat rest, the pan-holder just touches the skin (Fig. 60).To avoid the coldness of the pan, a piece of cork orleather is placed between the hand and the metal. The subject of experiment closes his eyes. A weight Touch. 107 is placed in the pan above the hand. A sensation ofpressure is felt. Sand is quietly poured into the samepan until the subject feels the pressure to be putting weights in the other pan the amount of in-crease can be measured. Now start with the sameweight as before and pour sand into the opposite panuntil the subject feels the pressure to be lighter. The Least notice-amount of sand that has been added represents the leastnoticeable change, or the threshold of change, in thepressure. Thus, if the weight at the start was 50& andthe amount of sand added was 35s, the least noticeablechange was 35s, or If of the original pressure. Several facts
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpsychop, bookyear1895
