Man and abnormal man, including a study of children, in connection with bills to establish laboratories under federal and state governments for the study of the criminal, pauper, and defective classes, with bibliographies . tuning-fork stand for making electrical contact50,100, or 200 times per second by meansof tuning forks the vibrations of whichare electrically maintained. Any of thetuning forks can be fixed in the slot inthe heavy cast-iron block. A platinumwire A projects vertically downwardfrom the lower prong of the fork, andat each vibration dips into a cup con-taining mercury and comp
Man and abnormal man, including a study of children, in connection with bills to establish laboratories under federal and state governments for the study of the criminal, pauper, and defective classes, with bibliographies . tuning-fork stand for making electrical contact50,100, or 200 times per second by meansof tuning forks the vibrations of whichare electrically maintained. Any of thetuning forks can be fixed in the slot inthe heavy cast-iron block. A platinumwire A projects vertically downwardfrom the lower prong of the fork, andat each vibration dips into a cup con-taining mercury and completes an electrical circuit. The current thus formed i>itaken to a small electro-magnet B placed between the prongs of the fork. Theebonite block supporting the electro-magnet and the mercury cup can slide along arod C to suit the lengths of the various forks. The level of the mercury in the cupcan be adjusted by a screw plunger. The mercury can be kept clean by passing acontinuous stream of water over its surface. The supply of waiter must be taken tothe instrument by india-rubber tubing. The amplitude of the vibration of the forkcan be varied by a lateral adjustment of the electro-magnet; a vertical adjustment. Fltr. 5.— Veruiei cijroiioscope. (Sanford.)
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherwashingtongovtprin
