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{"created":"2022-01-31T15:51:31.236836+00:00","id":"lit23168","links":{},"metadata":{"alternative":"Studies from the Yale Psychological Laboratory","contributors":[{"name":"Scripture, E. W.","role":"author"}],"detailsRefDisplay":"Studies from the Yale Psychological Laboratory 1: 97-100","fulltext":[{"file":"p0097.txt","language":"en","ocr_en":"SOME NEW PSYCHOLOGICAL APPARATUS\nBY\nE. W. Scripture.\nIn starting the Yale laboratory it was deemed best to provide ample facilities for the repair and construction of apparatus by establishing a serviceable workshop-equipment. In addition to the large amount of work done for the investigators of special problems, several pieces of apparatus of general use were invented and manufactured. Some of these, the multiple key (first model), the reaction-key and the switch-board have been described in the preceding pages. There are, however, three others that are deserving of mention.\nIn the first model of the multiple key, the two levers were hung on different axles; consequently the arcs described by the contact-points were not concentric. For most purposes this made little or no difference. For two of the numerous uses of the key it appeared quite desirable to avoid this difference of centers. In the first place it is geometrically evident that in using the contact E-U (fig. II) the upper point will slide sideways slightly as the key is depressed. This makes slight variations in the resistance to the current passing through the points. These variations are not noticeable except in a telephone-circuit ; there the result is to produce a grating noise in addition to the tone or noise sent through the telephone. The other objection is a somewhat similar one in regard to the contact D-S-T. The point T slides along the spring S and causes variations in the strength of the current.\nTo remove these objections a new key was built in which the lower lever works around the same axis as the upper one, so that any point of the upper lever striking the lower one will always touch it at the same place, no matter how far it is moved.\nThe new key is shown in fig. 31. The lower lever has two projecting arms that are hung on the axle of the upper lever. There is no necessity for the spring S (fig. 11) in the first key; consequently both contacts 7 and 3 are alike. Experience having shown the mercury cup to be better than the contact N-R of the first key, the latter has been omitted. Figures opposite the various contacts indicate the binding-posts to which they are connected.","page":97},{"file":"p0098.txt","language":"en","ocr_en":"98\nSome new psychological apparatus.\nThe vital point in the construction of the key is the concentricity of the levers. In the one already made for Clark University this has been carried out so well that both sets of contacts -7-8 and 3-4\nFig. 31.\ncan be adjusted to strike at the same time and maintain their contact through an arc of 10\u00b0. The rubbing of the upper contact against the lower one, as tested by the telephone, has been totally eliminated for 7-8 throughout the arc and for 3-4 throughout a somewhat smaller one.\nAnother piece of apparatus constructed is a pendulum-contact.\nThose who have used mercury contacts for clock-pendulums well know the continual trouble that they give when placed in the center of the arc of swing at the extremity of the pendulum. Relief has been sought by resorting to platinum contacts made when the pendulum is at the extremes of its arc. The sources of error in this method have made it almost inapplicable in scientific work.\nAfter wasting considerable time and money in these two ways, a contact-apparatus was invented which made platinum contact in the middle of the arc of swing. In this way the advantages of solid contact and mid-arc contact were gained together.\nThis clock-contact is shown in fig. 32. The support A carries the horizontal metal piece B with the binding-post C. The rubber block D, fastened to B, carries the metal arm E, which by means of its axle is in contact with the binding-post F. At the end of E there is a platinum point G which rests on another platinum point at the end of the screw H. This instrument is placed on the floor of the clock just far enough in front to clear the pendulum. A fine wire I is run from the arm E to a pin on the pendulum-arm J. If H is adjusted so that the platinum points just touch when the pendulum is at rest, any movement will break the circuit. When the pendulum is swinging, contact is made only at the lowest point of the arc.","page":98},{"file":"p0099.txt","language":"en","ocr_en":"Some new psychological apparatus.\n99\nOwing to the light weight of the parts and the smallness of the movement, the friction is exceedingly small.\nFig. 32.\nThe third instrument to be described is a new chronograph. The electric drum mentioned by Brass on p. 9 was a temporary arrangement which did such excellent service that the construction of a thoroughly durable apparatus was decided upon.\nThe drums used for physiological work, such as the Baltzar kymograph, are made to run at slow rates of speed. Those used for physical purposes, such as the K\u00f6nig drum, are not made for continuous running. For psychological work there is need of a very rapid drum running continuously as long as desired. In the Wundt1 chronograph a high rate of speed is obtained by using clockwork as the motor power. Such an arrangement is very expensive and is unsatisfactory in several w'ays.\nThe drum shown in fig. 33 is either a hand-drum or an electric drum. The cast-iron base is supported on three fixed and one adjustable leg. The drum itself runs on hardened steel centers\nPhys. Psych. 3 ed. II 279.","page":99},{"file":"p0100.txt","language":"en","ocr_en":"100\nSome new psychological apparatus.\nheld by two uprights bolted to the base. When the drum is to be turned by hand, a large wheel is placed on the axle as shown in the figure. With this weight the drum will run several minutes with\nFig. 33.\none impulse of the hand. When an electric motor is to be used, the wheel is removed and a pulley is placed on the axle. The motor is fastened to the base by a slide and bolt.\nThe carriage for the time-marker is mounted on rails planed like those of a lathe-rest. Rigidity is attained by the conical support for the rod.","page":100}],"identifier":"lit23168","issued":"1892-1893","language":"en","pages":"97-100","startpages":"97","title":"Some new psychological apparatus","type":"Journal Article","volume":"1"},"revision":0,"updated":"2022-01-31T15:51:31.236842+00:00"}