Page:The American Boy's Handy Book edition 1.djvu/116

Nearly three-fourths of the whole world is covered by water. Old Isaak Walton in his quaint book says that this vast expanse of territory is "Nature's storehouse, in which she locks up all her wonders." The previous chapters on fresh water and marine aquariums have already shown how a portion of the "wonders" may be kept in your own house, in what might be termed little glass side-shows to the great marine menagerie. This chapter will tell you how to make an instrument through which you can peep under the watery tent of the big show itself, and see the curiosities swimming about in their native haunts.

The water-telescope is not made of aqueous fluid, as its name might imply, but is a contrivance made of wood or metal, through which, when one end is partly submerged, objects beneath the water can be plainly seen that would otherwise be invisible.

It is astonishing how many fathoms of water become almost as transparent as air when viewed through one of these simple and amusing contrivances. In Norway, the fishermen make practical use of the water telescope when searching for herring shoals or cod, often by its means discovering new and unlooked-for fish.

All that is necessary is a long wooden box, a piece of glass for one end, and some paint and putty for making the seams