768. AUGUSTE PICCARD (1884 - 1962) Swiss physicist who explored the stratosphere by balloon and the ocean depths by bathyscope. Fine, bold signature on a small card adding place and date Apr. 4, 1848. Along with a T.L.S. by Piccard's son, who, with Don Walsh, reached the deepest point in the earth's surface, 1p. 4to., Solna, Feb. 23, 1972, sending some information, as well as a small S.P. 3 1/2" x 3 1/2", an image of his PX-15 mesoscaphe, signed at left. Together with a bold signature of Piccard's partner DON WALSH. Four pieces, very good. $75 - 100