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SCIENTIFIC.
SCIENTIFIC.
The period of the sun spot maximum passed about three years ago, but there still continues to be a few spots, as there always is even in the minimum. Within the past week a very large spot has traversed the sun's disc from the eastern limb to about the center. This motion of the spot is due to the rotation of the sun upon his axis, which is accomplished once in about twenty-five days; but sometimes a sun spot is carried along by an immense solar hurricane, compared to which a terrestrial tornado is but a gentle breeze.
The above spot is the finest which has been noticed at the University observatory this winter. It is almost large enough for a giant to play a game of marbles in, and use for his marbles Mercury and Mars, our moon and enough of Jupiter's and Saturn's moons to make up the required number.
One of the curious features of a sun spot is that to an observer with a common telescope it appears perfectly black and still it is of dazzling brightness.
—Experiments are being made by Prof. Nichols to determine whether the heat of chemical combination of iron is affected by magnetism.A weighed quantity of iron is dissolved in some acid,such as Aqua Regia and the rise of temperaure noted.The question is whether the rise of temperature and consequently the amount of heat will be greater or less when the iron, during the action,is subjected to the inductive action of a powerful electro-magnet. Theoretically the amount of heat given off without the magnet should exceed that given off with the magnet by a quantity equivalent to the mechanical energy set free in the fall of
iron, under the attraction of magnet, from an infinite distance to that at which the action takes place. This amount of heat would require delicate measurements for its detection, unless a very powerful magnet be employed.
The result of a series of experiments has proven however, that the amount of heat set free is much greater under the influence of the magnet than otherwise.
This result may be caused by the tendency of magnetic iron to form ferric salts, when under the same conditions, normal iron would form ferrous salts, or the magnet may tend to form a mixture of ferric and ferrous salts, corresponding to magnetic oxide of iron, while as in the other case, normal iron would form ferrous with perhaps a small admixture of ferric salts.
The action producing ferric salts would give off more heat than if ferrous salts were formed, just as the combustion of carbon is more intense when carbonic acid is formed than when carbonic oxide is formed.
It is not known that magnetic iron is different from normal iron in its chemical relations, but if the above explanation proves to be true this will be one of the most interesting results.
Perhaps the best and only way to prove that the products of a chemical action on magnetic iron differs from the products of a similar action on normal iron is to subject the products to a thorough chemical analysis. But there are serious objections to this process in our case, for there must always be an excess of acid, so as to insure a rapid and complete action, and ferrous salts have a tendency to change to ferric when there is an excess of acid in solution.