Figure 6. Brooke sounder, invented by Midshipman John M. Brooke, USN, at the
instigation of Matthew Fontaine Maury of the United States Naval Observatory in
1852. This was the first sounding device to abandon its lead at the bottom and
return with a sample. Initially, it was built with two hooks for release and
malfunctioned but was rebuilt with a single hook and used successfully in 1853.