Mahlon Loomis made many unsubstantiated claims about successfully making two-way wireless telegraph transmissions, beginning in 1866. This was a full decade before the introduction of Bell's telephone, but once that appeared, Loomis claimed his system was easily adaptable to wireless telephoning as well, and in this report made the -- once again unverified -- claim that he was now holding two-way telephone conversations through the air to an (unnamed) assistant located twenty miles (32 kilometers) away.
American Socialist, April 17, 1879, pages 126-127:
Professor Loomis appears to be enthusiastically engaged in carrying on his experiments in aerial telegraphy in West Virginia. Aerial telegraphy is based on a theory that at certain elevations there is a natural electric current, by taking advantage of which, wires may be wholly dispensed with. It is said that he has telegraphed as far as 11 miles by means of kites flown with copper wire. When the kites reached the same altitude or got into the same current, communication by means of an instrument similar to the Morse instrument was easy and perfect, but ceased as soon as one of the kites was lowered. He has built towers on two hills about 20 miles apart, and from the tops of them run up steel rods into the region of the electric current. The Professor announces that he has recently discovered that the telephone can be used for this method of communication as well as telegraphic instruments, and that of late he has done all his talking with his assistant, 20 miles away, by a telephone, the connection being aerial only. He claims that he can telegraph across the sea without wires other than those necessary to reach the elevation of the current. There seems to be no immediate possibility, however, of our getting on without poles and wires and ocean cables.--Cincinnati Commercial Review.