Although human sacrifice was discontinued in ancient times, the idea continues that the river god claims as his own any man who falls into the stream. Boatmen are often afraid to rescue such unfortunates, believing that the god, cheated of his sacrifice, would claim them as a substitute. It may well be that Chairman Mao Tse-tung is deliberately trying to break down this ancient superstition with his much-publicized swims in the Yangtze.

The entire operation is conducted from a safe distance by the crane-man, thus eliminating the danger of accident to ground-men, who are usually required for operating a mechanical trip.

The most significant part of the repair work was to seal the Thames Tunnel by 'shotcreting' it.

to sophisticate the understanding