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Show Why Many Deep Sea L FISH Are INVISIBLE! TIE recent investigations into the life of the deeper portions of the ocean have : brought to light an astonishing num- i her of forms of fish, and especially of prawns of a brilliantly red color, living in the ocean at a depth of 500 fathoms, or 3,000 k foot. "But astonishing as It may seem, these brilliantly colored fish and prawns, instead I of being conspicuous In the water at that depth, are almost invisible, when almost any i other color could bo easily seen. This led- the investigators to try and find out why I this particular depth of the ocean was as- 1 sociatod with Oils vivid red colored marine ! lire ' Accordingly photographic plates of great i sensitiveness were sunk in the sea to various 1 depths and the results recorded, the depth, i the time of exposure, the effect on tho plate i and various other factors being carefully ! considered. Then plates were submerged in i the water to various depths, having light filters, that is to say, being protected by a I glass of a certain color which would stop all I the rays of that color, just as a blue glass ' stops the red and yellow rays of sunlight and lets the blue rays through, while a redjj9, glass does the same for the red rays. $ii8.' This led to the wonderful discovery that atl the very point where the red marine life i3$fre, ? found, the imperfect transparency of thajn' water is such that the red part of sunlightf is absorbed, and consequently the light that'L filters through to tho region where the red'5 prawns dwell possess no red rays and coa-h sequently Is neutralized when striking upon':ilielf the prawn. Later It was found, however,'; fS, that in the far North the prawns dwelt at?" V-depths V-depths not so great, and there again esperi'--i mcnts were made and it was found that thel reason why these vividly-colored creatures' jfl; pli wore able to live safely nearer the surface'" in Northern waters was because the sun'3;!iwet rays struck the ocean at a greater angle'; p 4174 than when nearer the equator, and that con-; sequently they passed through an amount of; JUSA water equivalent to the greater depth, though Jr- tho angle at which they entered tho water rn t was such that it did not strike in so deeply ?.2i The pawn's bright color is his beat protection'' nt the e:act depth where he dwells; did nej jf' swim higher or lower he would he so easily ss-r visible to his enemies that the race would,!? B soon become extinct. rlL s |