Natural Telephone Line

There is a natural telephone liño in the Black Hills. The line runs between two mountains in the Blaofc Hill3 range, northwest of Rapiü City. On each side oL the valley, twelve miles widc, stand two high peaks, which tower above the other mountains and havo long been known as land marks. These mountains are several thousand feet high, and have rarely been scaled. so that but little is known of their topography. But some weeks ago a party of touri.sts deciiled to make the ascent, and they divided into two parties, ono for each peak, taking heliographs with them for the purpose of signaling to each other across the valley. The ascent was made and one of the party on the north mountain was surprisetl to hear voices, which apparently came out of the air. He moved his position, and the sound was no longer heard. By changing his position several times ha discüverecï that the voices were those of his friends on the other mountain. He called the attention of tho ethers to the phenomena, and when tho at '.ention of the opposite party had been attracted it was found "that an ordinary conversation in an ordinary tone of voice was plainly heard from one mountain top to the other. There was only one place on the mountain wli ore it could be heard, and thls ap :)pnral to form a natural telephone. Scientists say that the cause is to 'ie found in the form of the mountains, vhich serve as elliptical reflector if sound, the speakers being situated n the face, at the ends of the ellipse. n1 in the low density of the atmnsphere at th? altitude at which the ;jhenomena occur.