An attempt was made to propagate pulsed CW sound coherently over thousand-mile distances in the mid-Atlantic using the focusing properties of the sound channel. The sound field emanating from a 440-cps lumped source at the sound channel depth off Barbados was studied at stations 159 and 975 mi. away in the NNE direction. This field was probed in depth with a 3-dimensional array of hydrophones with the source on for 8- and 9-min periods followed by 2- or 1-min silent periods. While a moderately coherent field existed at 159 mi., inter-hydrophone correlation measurements indicated a sharply rippled wave front which was not at all stable in time. Individual hydrophone records showed large random instabilities with variation of intensity by a factor of 3 occurring within periods of a few minutes. At 975 mi. no coherent signal at all was detected on individual hydrophones although the source strength was eight times greater. A barely detectable inter-hydrophone correlation was observed. The negative results of this attempt are at least in part due to the irregular sound velocity structure of the sound channel as described in the accompanying abstract (F1), (This work was supported by the Office of Naval Research.)