"This map with the data shown thereon was prepared during the years 1936, 1937, & 1938 by Julian Cleveland Smith. M.E., E.E., LL.D., Member E.I.C. Assisting in this work were J. Napolean Longval. C.E., and Alberta A. Heath Jr. A novel type supersonic sounding machine designed and built by Julian Cleveland Smith M.E., E.E., LL.D. and Arthur S. Runciman, E.E., Assoc. member E.I.C. was largely responsible for the successful completion of this work"