748 MARINE PRODUCTS OF COMMERCE 



deeper waters than is possible by the use of the methods already described, and 

 therefore vastly extends the available sponging grounds; that the sponges on those 

 grounds are better and more abundant; and that operations may be conducted 

 under weather and water conditions which would prohibit the use of other meth- 

 ods. The disadvantages are that more capital and equipment are required, and 

 that there is greater peril to the life and health of the divers. 



The diving suit is of the usual type, completely covering the body with the 

 exception of the hands. It is made of 2 layers of waterproof cotton cloth with 

 rubber between, a tinned copper helmet, breastplate, and weighted shoes. The 

 helmet has 4 heavy glass windows, and a hose connection and relief valve at the 

 back. The automatic relief valve for the discharge of vitiated air does not appear 

 to be in favor with the sponge divers, who prefer the spring valve opened as 

 necessary by pressing against it with the back of the head. The pump is of the 

 usual type used by divers. The hose which conveys air under pressure to the hel- 

 met is of the highest quality; it is protected by a canvas jacket, and the weight of 

 the screw couplings between its sections is compensated in the water by the buoy- 

 ancy of cork floats. 



Sponge divers, both in the Mediterranean and in Florida, are almost exclu- 

 sively Greek, and the Greek type of diving boat is used in both places. The boats 

 are "double-ended," high bow and stern, and with considerable shear, features 

 which make them seaworthy and dry in any weather. They are usually rigged 

 with a spritsail, but all those in American waters now use gasoline engines, and . 

 are equipped with a cage of metal bars -around the propeller to prevent the foul- 

 ing and cutting of the hose and life line. Formerly, even in the engined boats, 

 oars were used in keeping the boat up to the diver as he moved over the bottom, 

 but experience has proven that the engine may be used for this purpose. 



Space will permit only a limited description of this method of sponging. When 

 the diver is fully dressed and the hose and life line are attached, the pump is started 

 and he lets himself over the side of the boat. As soon as he reaches bottom, he 

 gets to his feet and moves about in search of sponges. Owing to the resistance of 

 the water and buoyancy of his air-filled suit he is unable to walk in the ordinary 

 way, but progresses in a series of leaps upward and forward. As sponges are 

 found, they are placed in a bag, which, when full, is hauled to the surface on the 

 life line and an empty one sent down. Communication between the diver and the 

 boat is maintained by a code of tugs on the life line. 



The length of time that a diver can remain under water depends on the depth 

 and the physical powers of the man. On the Florida coast, in depths of 60 feet 

 or less, the shift is usually 2 hours down and 2 hours rest. In deeper water the 

 period of submergence is shorter and the rest longer. 



Divers in deep water are subject to the "bends," or caisson disease, due to the 

 release of air in bubbles in the blood vessels as a result of the rapid change from 

 the pressure in the helmet to that of the atmosphere when they are brought to the 

 surface. Owing to the comparatively shallow water in which diving is conducted 

 in Florida fatal or serious cases are few there; but the proportion of deaths and 

 disablement among the Mediterranean divers is high, and for their protection 

 the Greek laws prohibit marine diving in greater depths than 124 feet. This law 

 appears to be generally ignored. 



Neither naked nor machine divers eat until the day's work is completed. 



