In the deep‐sea seismic measurements which were commenced last summer on the Atlantis, the principal problems for which no good solution is in sight are connected with the cable. It seems likely that the best solution is to dispense with the cable altogether.Figure 1 shows the apparatus as used last year. It consists of a series of bombs, a series of seismographs, and an oscillograph‐chamber. The cable leading from the ship to the oscillograph is a wire rope which serves only to lower and hoist the apparatus. It is necessary to place the 600‐pound oscillograph‐chamber on the bottom of the ocean in such a way that the 4200‐foot string of seismographs and bombs shall lead away from it in a line which is very nearly straight. The actual distances from each bomb to each seismograph are determined from the travel‐time of the water‐wave. Only three tests have been made to date, but it is revealed by the water‐waves that the line of instruments did not extend to nearly its full length in any test. In one test the 20‐pound bomb was actually less than 600 feet from the oscillograph. Perhaps further practice in the maneuver of laying out the apparatus would overcome this difficulty to some extent, but it will always be difficult to stretch this line out straight without parting it. This is the first problem to be solved.