Answer.—Why the magnetic needle points northward is not positively determined. There are several theories but none of them explain all the phenomena of the needle. That which perplexes scientists most is that in every place the needle is subject to variations. By observations at Paris it was found that in 1681 the magnetic needle varied 2 deg. 30 min. to the west, in 1865 18 deg. 44 min. to the west. At London between 1580 and 1692 the needle varied from 10 deg. 15 min. E. to 6 deg. W. In Dakota Territory the average variation is 12 deg. 30 min. east, in Minnesota 11 deg. east, while in Montana it is 20 deg. east. S. V. Clevenger, United States Deputy Surveyor, says in a work on government surveys: “The needle does not point due north, except in a few localities, and at no place does it continue to point with a given angular distance from the north, for any stated length of time. It changes secularly, annually, diurnally, and hourly, and is further subject to fluctuations reducible to no method of tabulation. In the vicinity of iron in any shape, or magnetic sands, the needle is deflected toward the material attracting it. This perturbation is known as local attraction. The author has known the needle to vary 5 deg. in a distance of one mile, and 1 deg. 30 min. during two hours when stationed at one place.” The variation in the magnetic needle of Columbus’ compass was probably caused by some local attraction of which he knew nothing.
DISCOURAGEMENTS TO ANTARCTIC EXPLORATIONS.
Palestine, Ind.
Why is the north pole the object of more research than the south pole?
Subscriber.
Answer.—Soon after the discovery of America European navigators began to search the arctic zone for a passage to Asiatic countries which would be less dangerous and circuitous than that usually traveled. Although the object of polar expeditions has changed somewhat, yet one of the reasons which actuated them influences the explorers of the present time. The nearness of this pole has rendered it of greater interest than its southern counterpart. Expeditions are fitted out more easily for the shorter voyage. Relief can be procured with less delay. Other reasons are that from the closer neighborhood of the continents, and from the action of the Gulf Stream on the one side and the Japan current on the other, and from the fact that the earth is in perihelion during the winter season of the Northern hemisphere, and in aphelion during the winter of the Southern hemisphere, the Arctic Sea is more free from ice, which in the Antarctic region is an impregnable barrier in the way of discovery.
WAGES IN ENGLAND AND AMERICA.
Oskaloosa, Iowa.