Appletons' Popular Science Monthly, October 1899: Vol. LV, May to October, 1899Various
Philosophy
Appletons' Popular Science Monthly, October 1899: Vol. LV, May to October, 1899
Various
Science -- Periodicals; Technology -- Periodicals
The investigations of F. E. L. Beal of the Food of Cuckoos and S. D.
Judd of the Food of Shrikes in their relation to agriculture are
published in a single bulletin by the Department of Agriculture. Mr.
Beal finds that the food of cuckoos consists almost wholly of insects,
of which he has found sixty-five species in their stomachs, and
concludes that from an economical point of view they rank among our
most useful birds; and, in view of the caterpillars they eat, it seems
hardly possible to overestimate the value of their work. Mr. Judd
finds, from a very extensive examination, that the food of butcher
birds and loggerhead shrikes consists of invertebrates (mainly
grasshoppers), birds, and mice. During the colder half of the year the
butcher bird eats birds and mice to the extent of sixty per cent, and
ekes out the rest of its food with insects. In the loggerhead's food,
birds and mice amount to only twenty-four per cent. Its beneficial
qualities "outweigh four to one its injurious ones. Instead of being
persecuted, it should receive protection."
The Engineering Magazine is authority for the following: "The wrecking
of the steamship Paris on the coast of Cornwall and the difficulties
encountered in attempting to save her while a number of her
compartments forward are filled with water, lead Mr. Richards, in the
American Machinist, to suggest the applicability of compressed air.
'There is a means of expelling the water from the filled compartments
so obvious, and so certainly effective, that it seems unaccountable
that some engineer has not suggested it before this. Close the hatches
of the flooded compartments and drive the water out by forcing air in.
It would not make the slightest difference how big the holes might be
in the bottom, as the water would be expelled and kept out on the same
principle as in the old-fashioned diving bell.' This suggestion
carries with it a much larger and more important one--namely, the use
of air pumps instead of water pumps to save a leaking ship while
afloat. As Mr. Richards well remarks, the work of trying to pump out a
leaky ship is not only enormously wasted while it is going on, but it
is never finished. If, however, the water leaking into a compartment
of a ship be expelled by pumping air into the space, the work is done
so soon as the compartment is filled with air down to the level of the
leak. After that point is reached the ship is safe, no matter how
large the hole, and no further pumping is necessary."
Public-domain text, read in full here on John Shaqi.
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