Written by: Lex Protector|June 9, 2018
On this day i.e. on 10th June in the year 1902, Americus F. Callahan was granted a patent.
This patent was for an improved version of the envelope. This Patent was granted by USPTO with patent no. 701839. The main motive of this invention was to act in its primary capacity of securely inclosing and sealing the contents of the envelop and in the added capacity of revealing so much of the inclosure as may enable the observer to ascertain the destination of the same. This envelope was composed of thick paper and had a portion on it made of rice paper which was transparent through which the senders address could be seen. It was an important invention for the then highly considered mode of communication then i.e. postal service and made it more efficient.
By Lex Protector ')}
