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Sees, pinnacles of rock rising to wittiin a 

 few feet of ttie sea surface, sent many 

 ships of classicai times to the bottom. These 

 rocl< formations serve as valuabie guides to 

 divers searching for oid wreci^s. The one 

 shown here was traced by an echo sounder. 



The real problem is not that of finding a classical harbor town, but 

 of establishing its relation to the present coast. 



This can sometimes be settled quite simply by finding a person 

 who has been swimming in the area with a mask and fins, as I was 

 lucky enough to do at ApoUonia. Normally the most reliable course 

 is to refer to the archaeological journals that contain details of past 

 work on a particular site. It is ridiculous to expect to discover a 

 lost city without a clue. What is more usually the case is that a 

 classical port in some remote place was recognized by a traveler in 

 the eighteenth century, noted by a chart surveyor in the nineteenth 

 century, and studied by archaeologists in the twentieth century. 



Once a suitable site has been chosen and the precise nature of 

 the "digging" problem worked out, the next step is to obtain per- 

 mission to work there — both political and archaeological. The type 

 of site to be explored in part determines the work methods and 

 equipment. The basic gear - mask, fins, and snorkel — enables a 

 diver to work easily in shallow water. With this simple equipment 

 he can survey a complex structure in ten feet of water, and dive 

 down to a hundred feet for a short time, but such dives are not 

 recommended for beginners. 



If the water is deep, or if it is shallow but dirty, a diver must be 

 able to stay submerged for long periods, and must therefore have 

 an air supply. If he intends to stay down for long, he will also need 

 to wear a suit for warmth; even in the Mediterranean the water is 

 always cold below a hundred feet. 



Not counting the use of pure oxygen, there are three common 

 ways of feeding air to a diver. The oldest is the "standard" system 

 which provides a diver with a loose, watertight suit connected to a 

 heavy brass helmet, and heavy lead boots. The air supply is fed con- 

 tinuously through a pipe from the surface, at a pressure only slightly 

 above ambient water pressure. Air floods the suit and helmet, the 

 surplus bubbling out through a valve. This system enables a diver 

 to stay down for very long periods, it keeps him warm and com- 

 fortable, and provides telephone communication with the surface. 

 The enormous disadvantage is that the diver is cumbersome and 

 slow-moving, and a boat at least twenty-five feet long is needed to 

 house the air compressor, diving attendants, and spare gear that 

 is usually needed. 



The aqualung, perfected by Jacques- Yves Cousteau and Emile 

 Gagnan, is the exact opposite of standard gear. In this system the 

 diver swims with fins, carrying on his back a tank of air compressed 

 to 1 20 atmospheres, and the duration of his dive depends on the 

 capacity of the tank. The diver is fed air only when he breathes in, 

 and it reaches him at the ambient water pressure. The advantages 

 of this equipment are its lightness, mobiUty, and versatiUty, both 

 underwater and at the surface. And diving attendants are not 

 essential. The disadvantages are the Umited time it permits a diver 

 to stay down, lack of communication with the surface, and during 

 deep dives the divers must wear protective clothing for warmth. 

 Aqualungs have been used for most of the archaeological work 

 done since 1945. 



The new "surface-demand" system combines advantages of both 

 standard and free-diving systems. The air is fed to the diver from 

 a tank or compressor at the surface, and he breathes through a 

 demand valve attached to his back by a simple harness. The con- 



136 



