PHYSICS. ' 341 



even these failed to supply the need ; co-operation was required, this might be 

 accomplished through the National Educational Association.^ 



PROF. BELL'S INSTRUMENT FOR DETERMINING THE LOCATION 

 OF BULLETS IN THE HUMAN BODY. 



Section B held its meeting this morning in the William Molson Hall, the 

 large room being taxed to its utmost capacity with members of the Association 

 eager to hear Prof. Alex. Graham Bell's paper 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 inductive balance for the painless detection of me- 

 taUic masses imbedded in the human body. Prof. Bell being introduced to the 

 mee ing said that the subject he had chosen for his paper recalled the time of ex- 

 citement and painful suspense attending the time when the chief executive of the 

 United States lay nobly bearing prolonged suffering, and all the world watched 

 by his bed, and hoped and feared. In cases similar to that of the late President, 

 the great object was to find the location of the bullet. In the past the only way 

 in searching out a bullet was by probing with the knife and lance among tender 

 tissues and in fatal points. Science in the position it held at the present day 

 could surely do something to replace these barbarous operations, and to see if 

 something could not be done to prevent this dangerous system of j^roping among 

 quivering muscles he applied himself to work. 



The same problem had been considered by Professors Newcomb and Hop- 

 kins. It was perhaps natural for him as an electrician to attempt to apply elec- 

 tricity to the solution of the problem and for him personally to resort to the tele- 

 phone. The idea he had was that the question could be satisfactorily solved by 

 the joint use of the telephone and the induction balance. At the time he set to 

 work on this problem he had in his mind the result of some investigations he had 

 conducted in England. He exhibited several modifications of the induction 

 balance, which he described as two electric coils connected and at some distance 

 apart. He read in the newspapers of some experiments which had been made 

 by several electricians to determine the presence of the metals, the results of 

 which were that it was found that a magnetic needle in motion is retarded in its 

 rotation by being passed over copper bodies. When the President was shot he 

 immediately opened a series of investigations with the magnetic needle, and he 

 found that a disc of lead brought under a revolving magnetic needle caused a de- 

 viation of it. A bullet, however, had no noticeable effect on the needle. His 

 investigations in that way were consequently given up and he set to work with 

 the induction balance. He connected a telephone with one pole of an induction 

 balance and when the other came in contact with or near to a metallic body, a 

 perfect battery being formed, an electric current was sent through the connec- 

 tions, and a noise could be heard in the telephone. The difficulty was to give 



VI— 22 



