We have received many letters from readers in various parts of the country asking if they are at liberty to make electrical telephones, now that Bell's original patent 'has expired. In answer we say no. Bell's original patent was granted for 17 years, dated March 7, 1876, and in the fifth clause he claims The method of, and apparatus for,' transmitting vocal and other sounds telegraphically, as herein described, by causing undulations, similar in form to the vibrations of the air accompanying the said vocal or other sound, substantially as set forth." This claim was held by the Supreme Court to cover any kind of telephonic apparatus in which an undulatory electrical current was used. This patent expired March 7, 1893. Bell's second patent, dated January 30, 1877, covers the construction of the well-known Bell instrument and the parts thereof. This patent runs for 17 years from its date and will expire January 30, 1894. Not until that date will the public be free to make use of Bell's invention. Other. important patents are held by the American Bell Telephone Company which have long terms to run; these are explained in the company's advertisement on another page, to which we call the special attention of readers.
This article was originally published with the title "Patents" in SA Supplements 35, 899supp, 178 (March 1893)