Horizontal refraction in the ocean sound channel is a function of the acoustic mode number and frequency (chromatic aberration), and may lead to wide separations of long-range transmission paths. We consider the 1960 antipodal transmission from Perth, Australia, to Bermuda. The path has a southernmost point in the Indian Ocean, which depends sensitively on horizontal refraction associated with the north-to-south shoaling of the sound axis across the Antarctic Circumpolar Current. (Refraction by the current velocity is relatively small.) This southernmost point is at about 40 ¿S for low modes of relatively high frequency, and at about 50 ¿S for high modes of low frequency. ¿ American Geophysical Union 1991