446 BULLETIN OF THE BUREAU OF FISHERIES. 
back of the head. The fresh air is conducted in flat tubes from the intake 
toward the front side of the helmet, serving the double purpose of supplying 
unvitiated air for respiration and preventing condensation on the window. ‘The 
hose is of the best quality, covered with a canvas jacket to protect it from 
abrasion and with tight screw couplings between the sections, the weight of 
the unions being compensated for in the water by cork floats. The rest of the 
hose is of itself sufficiently buoyant when full of air. 
In preparing to descend, the diver dresses in heavy woolen underclothing 
and stockings, and thoroughly soaps his hands and wrists to permit pulling 
on of the rubber cuffs and to seeure closer contact at the wrists. With assist- 
ance he then crawls into his suit; the breastplate, covering the upper part of 
the breast, back, and shoulders, is inserted inside of the rubber yoke, which 
is provided with eyes fitting over corresponding screw lugs on the breastplate 
and the two are clamped to a water-tight joint with thumb screws and brass 
straps. Stout weighted leather shoes, brass soled and tipped, are then securely 
strapped on the feet. In the meantime the interior of the helmet has been 
washed and the air supply tested by placing water in the helmet to determine 
whether the air bubbles freely through the intake valve when the pump is 
operated. The pump is then started slowly and the helmet secured to the 
breastplate by an interrupted screw, the joint being made water-tight by means 
of a rubber gasket. The helmet is then lashed to the breastplate, the front and 
back weights of lead are lashed on, the hose brought under the left arm and 
lashed to the waist and the life line is fastened tightly around the body under 
the arms. 
The diver is then ready to descend, and with his burden of about 200 pounds 
is assisted to the side, where he either jumps, or rather falls overboard, or else 
climbs down the ladder, the pump being run more rapidly as needed to supply 
the air pressure commensurate with the depth in which the diver is working. 
The crew of a machine boat with their stations when at work is as follows: 
Two divers, who alternate on account of the arduousness of their duties, one rest- 
ing while the other is at work; these men are always particularly abstemious 
as to food and drink, no alcohol being used and the daily meals consisting 
of a cup of coffee in the morning and a hearty dinner at night when the day’s 
work is over. Three oarsmen; the bow oars are pulled each by one man 
sitting down, but the stern oarsman stands facing forward and pushes two 
sweeps, which are balanced by heavy weights near the handles so as to reduce 
the fatigue of rowing. Two pump men and one relief who manages the 
hose when not pumping. One life-line man, whose important duty it is to see 
that the life line is kept clear and that the signals of the diver are promptly 
regarded; experienced and careful men are required for this station, as the 
