Great caution must be used at all times, but especially on nearing the land. Old-fashioned ships use the lead and hand-line for finding the depth of water and nature of the bottom, so that by referring to the chart the navigator can tell just where he is. That apparatus is too clumsy for the swift steamship. We use Sir William Thompson's sounding-machine while the ship goes at full speed. A brass tube is fastened to the end of a piano-wire line. When this is lowered to the bottom the pressure of the water is exactly registered on a glass tube--somewhat resembling a thermometer--which is fastened inside the tube of brass. Upon reading the amount of pressure we know the exact depth. A cup on the end of the brass tube brings up a specimen of the bottom. [Illustration: THE GREYHOUND IN A FOG--A CLOSE SHAVE.] By taking soundings frequently when nearing the land, knowing the ship's course and her position at the last observation, one can prick out her track on the chart even in the heaviest fog. One never can tell what slant of tide or current is silently sending the ship toward the shore, so soundings are taken every fifteen minutes. The presence of a pilot on board is no excuse for the Captain whose ship gets into trouble. The lives of the fifteen hundred persons on board, the value of the cargo, which is always very great, and of the vessel herself, which is worth at least two millions, all are in his hands. But, as I said before, the responsibility never worries him. He simply watches everything closely. The heads of departments report to him every day, and should any emergency arise, he is kept informed of every new occurrence. How is it possible, we are often asked, to steer such a great vessel as the modern ocean liner? Steam and electricity have made the work almost seem like play. The senior officer on the bridge can tell at any moment just how fast the ship is going, how many revolutions the port and starboard screws are making per minute, just at what angle the rudder is set--in one word, all about the ship's progress. This is all reported to him on automatic registering machines.