"Still the thing is possible, and it must be done again and again, as the years pass on, by naturalists of all nations working with improved machinery and with ever-increased knowledge. For the bed of the deep sea, the 140,000,000 
Fig. 1.Brooke's Deep-Sea Sounding-Apparatus square miles which we have now added to the legitimate field of natural-history research, is not a barren waste. It is inhabited by a fauna more rich and varied on account of the enormous extent of the area, and with organisms in many cases apparently even more elaborately and delicately formed, and more exquisitely beautiful in their soft shades of coloring and in the rainbow-tints of their wonderful phosphorescence, than the fauna of the well known belt of shallow water, teeming with innumerable invertebrate forms, which fringes the land. And the forms of these hitherto unknown living beings, and their mode of life and their relations to other organisms, whether living or extinct, and the phenomena and laws of their geographical distribution, must be worked out."
There are two principal operations in exploring the bottom of the ocean: first, sounding to ascertain depth; and, second, dredging to bring up materials. Although much ingenuity has been expended in devices to bring up samples of the sea-bottom by the sounding-apparatus, yet dredging contrivances are now mainly relied upon for that purpose. To determine the depth with a sounding-line, it is customary to graduate it by attaching slips of different-colored cloths or leather which mark it off into sections, and give the means of determining the distance to which
