While looking at this short educational film from 1911, I thought of how I intend to see GRAVITY this weekend, about two astronauts who become untethered from their space ship and face a terrible death. For almost fifty years, pulp magazines modeled their images of what space suits would like like on the heavy, bronze-headed suits that deep sea divers would wear in an equally alien environment.This eight-minute short is about a diver planting explosives underneath a sunken ship to blow the river clear for ship traffic. Three quarters of it covers getting the diver into his suit. Most of the titles are about the enormously heavy weights he must wear underwater: almost ninety pounds of metal. The preparations are fascinating and the explosion is almost an anti-climax.