Telecommunication
The conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876. Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849. However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to "hear" what was being said. The first commercial telephone services were set-up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London.
Celesta
The celesta was invented in 1886 by the Parisian harmonium builder Auguste Mustel. His father, Victor Mustel, had developed the forerunner of the celesta, the typophone, in 1860. This instrument produced sound by striking tuning forks instead of the metal plates that would be used in the celesta. The dulcitone functioned identically to the typophone and was developed concurrently in Scotland; it is unclear whether their creators were aware of one another's instrument. The typophone/dulcitone's uses were limited by its low volume, too quiet to be heard in a full orchestra.