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SCUBA DIVING TECHNIQUE
The most important problem facing the primitive divers was the length of time they could stay under water. This they attempted to solve by rubbing their bodies with oil, which probably protected them against the cold and so reduced the consumption of oxygen, and by holding a sponge in their mouths, which probably had a psychological effect on the respiration.
The invention of air compression in the 18th century made developments in diving techniques possible, and in 1827 Siebe invented the diving suit with helmet. In this, however, the lead weights attached to the feet severely restricted freedom of movement.
In 1943 diving was made much easier by the invention of the Aqualung by Gagnen and Cousteau. This automatically adjusts the pressure of air supplied according to depth and water pressure. Using an aqualung a diver can move freely under water without any connection with the surface.
The diver setting out on underwater archaeology must have a rubber suit to protect him from the cold, a waterproof watch, a mask to allow him to see under water, a knife to extricate himself from weeds etc., fins to facilitate movement, a weighted belt, an under water camera, measuring instruments, plastic paper and a special underwater pen.
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