What Professor Pupin has apparently done is to free the wire from those miscellaneous disturbances known as "induction."
These are discussed by Professor Pupin in the paper here mentioned.
With the success of the Pupin coil, there came a larger life for the telephone.
It was in ascertaining that law so as to know where to place his inductance coils that Professor Pupin arrived at success.
A notable recent example is Professor Pupin's loaded telephone line.
Analogy in many a path such as that of Professor Pupin has served as a guide to the discoverer and inventor.
Fig. 35 shows the general relation of Pupin loading coils to the capacity of the line.
Hearing of this case, Professor Pupin induced the gentleman to allow him to attempt a photograph of the hand.
His researches resulted in the famous "Pupin coil" by the expedient now known as "loading."