CHAP. I. ] THE EQUIPMENT OF THE SHIP. 39 
bulbed tube by an air-tight india-rubber connection, and car- 
ries at its exit another piece of tubing for a purpose to be 
mentioned presently. The upper part of the apparatus is sup- 
ported by the clamp m, and by the bent rod f, which clamps 
firmly on to the lower part of the bulbed tube. The flask is 
supported in the water-bath g by the clamp /, attached to 
the retort-stand #, which in its turn is lashed to the blow-pipe 
table. 
When the apparatus is to be used, a sufficient quantity of 
boiled distilled water is introduced into the bulb, and the cork 
d pushed over the opening ¢. The sea-water to be examined is 
run directly into the flask from the deep-sea water -bottle by 
means of a tube with a narrow opening reaching to the bottom 
of the flask, the tube being gradually withdrawn until the flask 
is overflowing. The opening c in the tube is then brought just 
below the lower surface of the cork, which is pressed tightly 
into the neck of the flask. A certain amount of water dis- 
placed by the cork rises into the bulb, and the tube is carefully 
drawn upward till the opening is well within the cork, and 
therefore closed. A small vacuum is thus produced, causing 
the immediate appearance of air-bells in the water. The re- 
ceiver 6 is now attached, and the water brought to boiling by a 
hand spirit-lamp, and kept so until the whole of the air has been 
expelled, which takes from six to eight minutes. While the wa- 
ter is still boiling, the india-rubber tube on the exit tube of the 
receiver is closed with a glass stopper so tapered that at the 
point it slips easily into the tube, and, being pressed in, closes 
it tightly. The receiver is now hermetically sealed at the up- 
per contraction, and connection made between the bulb and the 
flask by pushing down the tube until the hole ¢ is below the 
cork. A lively disengagement of gas commences, which is kept 
up by heating the water in the water-bath, the water being 
brought slowly to the boiling-point, at which temperature it is 
retained for some time. When it is judged that the gas has 
