sentences:  Before she reached San Diego later in December 1923, she had accumulated much data beneficial to the study of the movement of sound waves through water and measuring their velocity under varying conditions of salinity, density, and temperature, information essential both to depth-finding and radio acoustic ranging.Upon arriving in California, Heck and "Guide" personnel in consultation with the Scripps Institution developed formulas that allowed accurate echo sounding of depths in all but the shallowest waters and installed hydrophones at La Jolla and Oceanside, California, to allow experimentation in the Pacific Ocean with radio acoustic ranging.Under Heck's direction, "Guide" then conducted experiments off the coast of California during the early months of 1924 that demonstrated that accurate echo sounding was possible using the new formulas.