Page:Popular Science Monthly Volume 3.djvu/273

Rh examination, and it became desirable to devise means of bringing up larger amounts of matter. Many contrivances Lave been made for this purpose. Sir John Ross, in 1818, invented a machine for this purpose, called the "deep-sea clamm." A large pair of forceps were kept asunder by a bolt, and the instrument was so contrived that, on the bolt striking the ground, a heavy iron weight slipped down a spindle and closed the forceps, which retained within them a considerable quantity of the bottom, whether sand, mud, or small stones. By this arrangement Sir John Ross brought up six pounds of soft mud from a depth of 6,300 feet.

In the year 1854, J. M. Brooke, passed midshipman in the United States Navy, contrived the arrangement known as "Brooke's Deep-Sea Sounding-Apparatus," of which all the more recent contrivances have been to a great extent modifications and improvements, his