Upon the electrical experiments to determine the location of the bullet in the body of the late President Garfield; and upon a successful form of induction balance for the painless detection of metallic masses in the human body . d a cam M pivoted in the u]iper disk andworking in a slot N in the lower disk. In order to prevent any movement of the coils, exceptingthat produced by the adjusting-key O, each coil was placed ina recess turned out in its ebonite disk, the edges of which werebevelled as shown at R. Paraiiine was then poured in so asto till up each recess. But this alone did not preve
Upon the electrical experiments to determine the location of the bullet in the body of the late President Garfield; and upon a successful form of induction balance for the painless detection of metallic masses in the human body . d a cam M pivoted in the u]iper disk andworking in a slot N in the lower disk. In order to prevent any movement of the coils, exceptingthat produced by the adjusting-key O, each coil was placed ina recess turned out in its ebonite disk, the edges of which werebevelled as shown at R. Paraiiine was then poured in so asto till up each recess. But this alone did not preventslglit pulsation of sound when the instrument was swayed fromside to side, and a very slight pressure of the linger on the thinportion of the ebonite plate under the coil B was sutticient todestroy the balance. This was remedied by strengthening this portion by meansof a rod of ebonite, which passed up through the centi-e ofthe coil and thi-ough a slot I, in the upper ebonite plate, andwas clamped firmly after the adjustment of the instrumentby an ebonite thunil)-screw II. This, however, increased thedifficulties of adjustment. When the coils were adjusted tosilence, then the tightening of the thmub-screw II disturbed a. 86 the halaiice ; and if the tliniuli-screw H was tightened tir8t,then the adjustment conld only he made hy a series of jerks,on account of friction. In pi-actice we found it l)est to adjustthe instrument almod to i-^ilem-e, and tlien the tightening <if thethumh-screw H completed the halance. This was the form of apparatus at wliich we liad arrived atthe time of the death of President (Tarliel<l. The difficulty of adjusting the coils led me uUimately to theidea of the apparatus shown in Figs. 21, 2:2, 23, 24, which isthe most practical form of the instrument yet devised. jp^ Tlie two exploring coils A B (Fig. 21) arearranged as shown, in arecess turned out in asingle l)loclv of wood coils are tempo-rarily connected with atelephone, hattery an
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Keywords: ., bookauthoryapamphl, bookcentury1800, bookdecade1880, bookyear1882
