National Geographic : 1939 Oct
How deep is the mud under the ocean? FOR centuries, man has only guessedat the depth of the sand, gravel, and mud on the ocean floor. Now he's getting the facts thanks to a new technique developed by Dr. Maurice Ewing of Lehigh University, who, dur ing the past few months, has been sounding the depth of ocean-bottom sediment with the aid of deep-sea bombs and recording instruments, the delicate timing of which is entrusted to six Hamilton railroad watches. Says Dr. Ewing of the Hamiltons used in these experiments: "Their performance was... remarkable. Deviations from schedule greater than 2 seconds were not allowed. The watches ... were subjected unavoidably to magnetic fields in the galvanometer magnets, and those in the bomb-firing mechanism were situated only 100 feet from the T.N.T. bombs (some as large as 20 pounds were used) at the instant of explosion. Even under these adverse conditions, the watches gave good service throughout our three months of work in Bermuda." Thus Hamilton, long regarded as the finest watch on land and in the air, adds one more triumph to its outstanding record of accurate and faithful performance-this time at the very bottom of the ocean. All Hamiltons have 17 or more jewels, precious metal cases. $37.50 to $5000. Made in U.S .A. Write for illus trated folder. Important: All genuine diamond cased Hamilton watches are stamped Hamilton on the back of the case. Hamilton Watch Company, 934 Columbia Avenue, Lancaster, Pennsylvania. WILSHIRE. (top) Thin as a wafer. 17 jewels. 14K natural gold filled. Flexible lugs. 18K applied gold numeral dial, $52.50. Two tone gilt marker and Roman numeral dial (shown), $50. HELENA. (center) Excitingly different. 17 jewels. 14K natural gold-filled. With 18K applied gold numeral dial and cord only, $50. BAGLEY. (bottom) 17 jewels. 10K natural gold-filled. 14K applied gold numeral dial (shown), $40. Black numerals, $37.50. Hamilton's experience building watches for railroadmen insuresgreatestpossible accuracyin every other size and gradethatHamiltonmakes. LOOK OUT 3 MILES BELOW! Shortly after this Hamilton-timed recorder reaches bot tom, a Hamilton-timed bomb will explode on the ocean bed one-half mile away. The recorded vibrations indi cate the depth of the sediment at the bottom. Three recorders and bombs are used in each sounding. "Mention the Geographic-It identifies you."