sci6181881.jpg
1881-06-18: PROFESSOR A. E. DOLBEAR'S NEW TELEPHONIC SYSTEM.,Prof. Dolbear's exhibit for the Paris Electrical Exhibition
PROFESSOR A. E. DOLBEAR'S NEW TELEPHONIC SYSTEM.,Prof. Dolbear's exhibit for the Paris Electrical Exhibition
sci6181881.jpg
1881-06-18: PROFESSOR A. E. DOLBEAR'S NEW TELEPHONIC SYSTEM.,Prof. Dolbear's exhibit for the Paris Electrical Exhibition
PROFESSOR A. E. DOLBEAR'S NEW TELEPHONIC SYSTEM.,Prof. Dolbear's exhibit for the Paris Electrical Exhibition