E. A. Delisser, L.S. and C.E., Bogantungan, who assisted me in my calculations, and furnished many useful suggestions.
J. Brunton Stephens, Brisbane, who persuaded me to publish my theory, and who also undertook the work of correction for the press.
J. A. Clarke, Artist, Brisbane, who contributed to the Illustrations.
Lyne Brown, Emerald,—(photographs).
F. Rothery, Emerald,—(models).
and—A. W. Voysey, Emerald,—(maps and diagrams).
