COLD IN DAKOTA.
Chicago, Ill.
In the interview with Mr. Geo. B. Armstrong, Register of the Government land office at Huron, D. T., recently published in The Inter Ocean, he asserts, substantially, that it is colder in Chicago with the mercury 5 deg. below zero than it is in Huron with the mercury 35 to 38 deg. below. A number of us, who swear by the Curiosity Shop, have got into a dispute over this statement and all agree to leave it to the editor of “the shop” to decide the matter. The question is: Is it as cold in Huron, D. T., as in this city, on the average?
G. H.
Answer.—In one sense of the word, it is unquestionably colder in Huron than in Chicago. But Mr. Armstrong has not left our readers in doubt as to his meaning. He distinctly says: “With the mercury in the thermometer as low as 35 and 38 degrees below zero, we do not suffer so much as the people in Chicago with the thermometer at 5 degrees below zero. The air is dry and comfortable.” Here he clearly discriminates between the cold of the atmosphere and the sense of cold experienced by human beings. There is no ground for dispute as to the comparative average winter cold of the climate of Southern Dakota in and about Huron, and the same at Chicago. The thermometer shows that the former is several degrees greater than the latter. But taking cold in the second sense of the word, “the sensation produced by the escape of heat” from the body; “chilliness or chillness”—see Webster’s second definition—every one knows by actual experience that this depends to a considerable degree upon the dryness and stillness of the atmosphere and the state of the body. Exposed to a high wind in humid atmosphere not more than 5 or 6 degrees below zero, a person may freeze to death, when he would endure 35 or 40 degrees below zero in a dry, still air without serious suffering. Such air is classed among the poorest of all heat conductors; it belongs rather to non-conductors. The sensation of cold is due to the conduction of heat from the body more rapidly than the vital forces can replace it. Moist air in rapid motion carries off heat with great rapidity. When the skin pores are open a considerable part of the fluids of the body exudes through them, dampens the garments, and so renders them better conductors. The cold and wind evaporate this moisture in the garments. Evaporation is a cooling process; so when the pores are not kept almost sealed up by steady cold the body suffers loss of temperature both by increased conduction and evaporation. Observations of the United States Signal Service denote that the atmosphere of the region of Dakota under consideration is dryer, stiller, and less subject to extreme changes than that of Chicago; so that it is possible that, while in one sense of the word cold, it is certainly colder in Huron than it is in Chicago, in the other sense it may be no colder or not so cold there as here. This is plainly a question of personal experience, and the best that Our Curiosity Shop can do to settle this dispute is to give the above facts, and add that the testimony of many credible witnesses who have tried both climates is to the effect that, taking the winter through, one feels the cold there no more, or not so much as here. If a wager turns on our decision, taking the word cold in its first sense, the answer given above is definite and positive; taking it in the second sense, it is indecisive; a case for “a draw.”
ANCHOR ICE.
Laporte City, Iowa.—In the Curiosity Shop for June 14 I see a correspondent asks an explanation of ice forming at the bottom of rivers and remaining there. I saw this ice for the first time three years ago the past winter, at Waterloo, in this State, where business kept me most of the time. It excited my curiosity, and I studied it until satisfied of its origin. The Cedar River runs through the city, and a dam is built across it giving a power of about eight feet fall. A short distance below this is a bridge over 600 feet long. The space between the dam and the bridge is a rock-bottom rapids. Having occasion to cross the bridge frequently I noticed this ice attached to the rocks under water after the weather became cold, but not cold enough to form a solid sheet of ice on the pond. It disappeared and came again as the weather changed to warm or cold, but ceased to be formed after the pond was covered with a solid cake of ice, always forming at the beginning of cold weather. I concluded it was caused by the formation of fine crystals of ice on the pond not yet frozen together, which, as they were carried over the dam, were mixed in the surf below and driven against and stuck fast in the fine moss covering the rocks, always attached to the side of the rock facing the fall, the first crystals presenting points to catch the next, and so the mass, which appeared like water-soaked snow, grew under the water by accretion, the water being as cold as the ice itself could not thaw it. I think if the correspondent will examine he will find anchor ice is formed in rapids or at the foot of falls draining a smooth expanse of water before the water becomes covered with a solid sheet of ice, and always on the up-stream side of the rocks in the bottom.
T. A. Kellett.