11 P.M.
* * * * * The details of the exchange were simple . Hanley , with only one mechanic , would hover at the zero-height , his Wasp lighted so that we could see it plainly . The wind drift , according to forecast , would be southerly . At 11 P.M. Hanley would release from his Wasp a small helium-gas baloon-car -- a ten-foot basket with the supporting gas bag above it , weighted so that it would slowly descend into the depths , with a southern drift . Our flyer , invisible and soundless , would pick up the baloon-car at some point in its descent . The gold would be there , in a black casket . De Boer would take the gold , deposit Jetta and me in the car , and release it again .