The next night they reappeared. And the next and the next. Now they began earlier than before—in fact, no one knew when they had started, for they were sounding when the night’s business died down sufficiently for them to be heard. But each night, it was noticed, the interval between the signals was exactly one minute longer than the night before.
Occasionally the weird whispers ceased for a night or two, but always they resumed with the same insistence, although with a newly-timed interval.
This continued until early in July, when the pause between the calls had attained more than thirty minutes’ duration.
Then the length of the lulls began to decrease erratically. One night the mysterious summons would be heard every nineteen and a quarter minutes; the next night, every ten and a half minutes; at other times, twelve and three-quarters minutes, or fourteen and a fifth, or fifteen and a third.
Still the signals could not be deciphered, and their message—if they contained one—remained a mystery.
Newspapers and scientific journals at last began to speculate upon the matter, advancing all manner of theories to account for the disturbances.
The only one of these conjectures attracting widespread attention, however, was that presented by Professor Howard Whiteman, the famous director of the United States naval observatory at Washington, D. C.
Professor Whiteman voiced the opinion that the planet Mars was trying to establish communication with the earth—the mysterious calls being wireless signals sent across space by the inhabitants of our neighboring world.
Our globe, moving through space much faster than Mars, and in a smaller orbit, overtakes its neighboring planet once in a little over two years. For some months Mars had been approaching the earth. At the beginning of June it had been approximately 40,000,000 miles away, and at that time, Professor Whiteman pointed out, the strange wireless calls had commenced. As the two worlds drew closer together the signals increased slightly in power.
The scientist urged that while Mars remained close to us the government should appropriate funds to enlarge one of the principal wireless stations in an effort to answer the overtures of our neighbors in space.