Scientific American, Volume 40, No. 13, March 29, 1879: A Weekly Journal of Practical Information, Art, Science,; Mechanics, Chemistry, and ManufacturesVarious
Science
Scientific American, Volume 40, No. 13, March 29, 1879: A Weekly Journal of Practical Information, Art, Science,; Mechanics, Chemistry, and Manufactures
Various
Science -- Periodicals; Technology -- Periodicals
TASTE FOR READING.--Sir John Herschel has declared that "if he were to
pray for a taste which should stand under every variety of
circumstance and be a source of happiness and cheerfulness to him
through life, it would be a taste for reading." Give a man, he
affirms, that taste, and the means of gratifying it, and you cannot
fail of making him good and happy; for you bring him in contact with
the best society in all ages, with the tenderest, the bravest, and the
purest men who have adorned humanity, making him a denizen of all
nations, a contemporary of all times, and giving him a practical proof
that the world has been created for him, for his solace, and for his
enjoyment.
* * * * *
AFRICA CROSSED AGAIN.
Information has been received by way of Lisbon, March 12, that the
Portuguese explorer, Pinto, has succeeded in traversing Africa from
west to east, and has reached Transvaal. The latitude of his course
across is not mentioned.
* * * * *
CURIOUS FACTS IN MAGNETISM.
At the meeting of the New York Academy of Sciences February 17th, the
article in the March number of _Harper's Magazine_, entitled "Gary's
Magnetic Motor," was incidentally alluded to, and Prof. C. A. Seeley
made the following remarks: The article claims that Mr. Gary has made
a discovery of a neutral line or surface, at which the polarity of an
induced magnet, while moving in the field of the inducing pole, is
changed. The alleged discovery appears to be an exaggerated statement
of some curious facts, which, although not new, are not commonly
recognized. If a bar of iron be brought up, end on, near a magnetic
pole, the bar becomes an induced magnet, but an induced magnet quite
different from what our elementary treatises seem to predict. On the
first scrutiny it is a magnet without a neutral point, and only one
kind of magnetism--namely, that of the inducing pole. Moreover, the
single pole is pretty evenly distributed over the whole surface, so
that if iron filings be sprinkled on the bar they will be attracted at
all points and completely cover it. Now, if while the bar is covered
by filings it be moved away from the inducing pole, the filings will
gradually and progressively fall, beginning at the end nearest the
inducing pole and continuing to some point near the middle of the bar;
the filings at the remote end will generally be held permanently. When
the bar is carried beyond the field of the inducing pole it is simply
a weak magnet of ordinary properties--_i. e._, of two poles and a
neutral point between them.
Public-domain text, read in full here on John Shaqi.
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