The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 100
Fig. 66 … Fig. 67 owing to their general adaptability, have nearly supplantedall other forms for general use. For a long time they labouredunder the disadvantage of what is known as packing,which resulted from the gradual settling down and consoli-dating of the carbon granules, so that the loose contacts,…
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer03inte-333-205.webp)
