By Dan Beard
Fig. 60.
Wooden Water-Telescope
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.
How to Make a Wooden Water-Telescope.
All that is necessary is a long wooden box, a piece of glass for one end, and some paint and putty for making the scams water-tight. Fix the glass in one end of the box, and leave the other end open to admit the eyes of the observer, as shown in the illustration (Fig. 60, above).
Fig. 61.
A Tin Water-Telescope
A Tin Water-Telescope,
is a funnel-shaped tin horn, about three or four feet long, eight to ten inches in diameter at the bottom, and broad enough at the top to admit both eyes of the observer (Fig. 61). Sinkers should be soldered on near the bottom, as shown in the illustration (Fig. 61, above). This in a measure counteracts the buoyancy of the air contained in the water-tight funnel, and helps to submerge the big end.
The inside of the funnel should be painted black, to prevent the light from being reflected upon the bright surface of the tin.
If any difficulty is found in procuring a circular piece of glass, the bottom may be made square and square glass used, and fitted into a leaden frame made for the purpose.
Any tin worker can, at a moderate cost, make an instrument like the one just described.
A water-telescope will add greatly to the entertainment of a boating party or picnic, furnishing a new and novel feature that will become popular wherever it is introduced.
Mr. Fred Holder tells me that while collecting marine animals with his father, Dr. Holder, the naturalist, they had a boat built with a glass in the hull, arranged and worked upon the same principle as a water-telescope. It was of great service where the water was not too deep. While one person rowed the other watched the bottom, which Mr. Holder describes as having the appearance of a beautiful panorama passing beneath him. Fish of all colors and forms filled the intervening space, and sometimes a "devil fish " would cross the scene, flapping its great wing like fins as it flew rather than swam through the clear water.
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