"Professor," remarked Joe, "did you not say that when the sun came out bright and hot, it dried up the fog? and is not the fog the very thing that keeps the sun from coming out?"
"Yes, my dear; but fogs usually gather at night, and when the sun rises in the morning, he goes to work at once to heat them up and make them disappear. But when he finds them very thick, and is hindered by cold air, he may be a good part of the day in working his way through, or he may even have to go down before he is able to show himself. Generally, however, he gets help from the wind, and then the fog goes off in a hurry."
"Is there no way," asked Gus, "of knowing when the wind will spring up, and give us some clear cold weather? Ted Wynant's cousin has an ice-boat, and we are all waiting for a ride on the river."
"There is Old Probabilities," said Jack; "but he can only tell a day or two ahead, and seems rather uncertain at that, and afraid to express a decided opinion. It is a little this or a little that, a little cloudy or a little cooler, and the wind is to blow a little in nearly every direction. Most people laugh when they talk about him, as if he was not of much account, or had grown stupid in his old age. If he would only foretell a hurricane or a deluge, and bring it around, why, then we would know what he is good for."
"Such a test would be rather costly," said the Professor, smiling. "It is better to give the old gentleman a little time to establish his reliableness; for in truth he is yet very young—a mere child of eight or ten years. And considering that he undertakes to forewarn our whole country as to the coming weather, so that everybody will have time to get ready for it, we must admit that he is doing all that his age warrants."
"Where does he live?" asked Gus.
"We have been talking somewhat absurdly," replied the Professor. "Instead of a single person, there is what is called the United States Signal Service, which has been in operation eight or ten years, and comprises some two hundred or more men, scattered all over the country, from Maine to California, and from the Gulf of Mexico away out to the Northwestern lakes. The men at these various stations watch the weather very closely, and at a particular time every day send word regarding it by telegraph to the main office at Washington, where the different reports are carefully studied, and an opinion formed as to what the weather is likely to be in different sections of the country during the next twenty-four hours or more, and the result is then published in the daily newspapers and at the numerous post-offices throughout the land. The matter is yet somewhat uncertain, and occasionally mistakes are made."
"But will they ever get so that they can tell exactly every time?"
"We hope so. The warnings given are usually right, and are becoming more and more reliable every year. In 1872 it was estimated that about seventy-seven out of a hundred of them were found to be correct; more recently they have been declared accurate about ninety times in a hundred. So, you see, good progress is being made; and the Signal Service system is becoming very useful to the nation, for property and life can often be saved from destruction when the approach of a severe storm is known.
"The New York Herald has encouraged the study of the weather for many years, and its managers now send word to England by the Atlantic cable when a storm is to be expected there. They have lately sent notice of so many ugly ones, which have promptly arrived, that our English cousins are complaining of the unfair treatment of the Herald."