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sel is actually equivalent to the differ- ence between the weight of the water displaced by the vessel when light, and ' that displaced by her when loaded to the greatest safe depth of immersion. The ton measurement upon which freight is charged is calculated at 40 cubic feet; the difference between that and the ton of 100 cubic feet, represents the dead weight or displacement of the ship when light, or 60 per cent of the whole, 40 per cent only being ayailable floating power for cargo. Ques.--What is meant by the lee shore. Is it not the shore under which you make a lee? dictionary would tell you at once. A lee shore is that shore on which the wind blows and on which the sea breaks with its greatest force. that shore from whence the wind and weather comes. To make a lee we get up under a weather shore. There are many people who get the lee shore nusxed up with the weather shore on accotint of in making a lee it is necessary to take the weather shore in order to do so. To the novice the weather shore is the shore on which the wind blows and the lee shore the shore, the wind comes from. Windward and weather are synonymous, meaning that point of the compass from which the wind blows. The weather shore is the shore to windward; the lee shore the shore to leeward, or on the lee side of the boat. Ques.--I am in a sailing vessel; and the true course to my destination is NE, and the wind is NE. I put ther as close to the wind as she will sail and make progress; now, what I want to know is, why do I have to allow easterly Var. and ° Dev. to the right and westerly Var and Dev. to the left of the course by com- pass in order to get the true course on the chart the vessel has made? Why can't I correct my course in the first place and allow Ely. Var. and Dev. to the left of the true course and Wly. Var. and Dev. to the right?' Ans--The course of a vessel beating to windward is gov- erned by the wind. You cannot tell what your compass course is going to be till you have placed your vessel in position to take the wind to the best possible ad- vantage. Dey. mean a swing of the compass card to the right, and Wly. Var. and Dev. a swing of the card to the left, and since the vessel's head follows the card, her course must be influenced by these cor- rections in the same way. With Ely. Var. or Dev. the true course must be to the right of the course as indicated by the compass, so that to get the true direction the ship has gone or is going over the ground, you must allow the amount of your correction to the right of the course as shown by. compass. With Wly. Var. and Dev. the true course cor- Ans.--A reference to. any' The weather shore is . passed, You_know that Ely. Var. and . TAE Marine REVIEW responding to the compass course lies on the left hand side of the compass course. When the Var. and Dev. are not allowed for the true direction the ship is going in is either to the right or to the left of the 'course as shown by the compass. If the compass course is NE with 14-pt, Ely. Var. and %4-pt. Ely. Dev., the true course the ship has made over the ground is NE34E, because the card is swung to the right; 34-pt. of what a true compass would indicate; hence, in steering the course NE by compass with the card turned aside 34-pt. NE is where NE34E should be. If it were desired to steer NE true in the first place and the ship's head was not guided by the wind, then all that would be necessary would be to allow the opposite way from what Ely, and Wly. mean. Thus, to make a true course of NE with 34-pt. Ely. cor- rection, we apply it to the left of the true course because if it was not allowed for we know it would carry us to the right of the course steered by compass. Tobe able to apply the Var. and Dev. in the, first instance the ship must be able to go in any direction, against the wind as well as with the wind. The course of a vessel beating to windward is guided by the direction of the wind, hence to know the true direction the ship is making good it becomes neces-: sary first to establish the compass course, and as I said before, the compass course is controlled by the direction of the wind. A sailing vessel with a fair wind can al- ways steer a compass course that corre- sponds to the true course desired to be made good. Ques.--What is meant by the smooth of the sea, and what is its cause? Ans. --During heavy gales, when very high seas are running, or even in a moderate gale 'of wind, it will be observed that at intervals of every few minutes a lull in the sea takes place, that is, the sea is not so high nor violent. This lull is what is called a smooth. These smooths | or lulls occur after the three or four largest seas, which occur in groups, have Vessels bucking into a heavy sea and then desiring to come round and run with it, or vice versa, that is, after having run: with it and now desire to run into it, wait for one of these smooths, and when it comes starboard the helm and come round as quickly as possible before the next group of heavy seas break and have an opportunity of catch- ing the vessel in the trough of the sea. This is a much easier and safer manner than maneuvering the vessel so as to' encounter the full force of the trough. The lulls that take place in relation to the sea also take place in relation to the wind. The grouping together of these larger waves than. the general run is caused by 'the exceptional force of the 31 squalls which occur at intervals in nearly every gale of wind. ' Ques.--What is heave of the sea, and when do you have to figure for it? Ans. --When a vessel is steering or running more or less in the trough of a heavy sea, the effect is to drive her to leeward, and this is expressed either as the heave of the sea or the send of the sea. It goes without saying that a shallow ves- sel will be lifted off more than a deep vessel, and for this reason no rule can be given, the master being obliged from experience to estimate the quantity for his vessel. -It would be allowed for in the same way as leeway.. Ques.--What is meant by the expres- sion "ship's displacement,' and how 1s it determined? Ans.--The displacement of a ship is the volume of that portion of her hull that is immersed or below the surface of the water, or which has dis- placed an equal volume and now occu- pies its place. Displacement is properly expressed in cubic feet, giving the meas- ure of the place or hole-in+the-water filled by the ship. As the weight of the vessel as she swims is exactly the weight. of the water displaced, it is convenient to express the displacement as so many tons, meaning tons.of water at so many cubic' feet to the ton. About 35 cubic feet of ordinary sea water weighs 2,240 pounds; or- a long ton." This is ona basis of 64 pounds to the cubic foot. A cubic foot of fresh water weighs about 62.3 pounds, or about 36 cubic feet to the long ton.. When we say that a ves- sel's displacement is 5,000 tons, it means that her hull shoves aside enough water so that if it could be weighed it would amount to 5,000 tors. Any floating sub- stance or object will displace its own weight in the water, hence if its weight be known the amount of water displaced will be equal to this weight. A substance that will not float will displace its own volume. Knowing the volume we can easily determine the weight or cubic measure of the water displaced; and similarly, if we do not krow the vol-~ ume we can ascertain it by weighing or measuring the amount of water displaced. Water has a buoying effect or pressure and its floating power is equal to its own weight; that is, a cubic foot of fresh water will buoy up a weight of 62.3 pounds, while a cubic foot of sea water will buoy up 64 pounds, This, of course, means any substance whose spe- cific gravity is less than that of water, or any substance if it be so shaped that it is capable of floating, such as an iron kettle, etc. If that portion of a ship's hull immersed measures 200,000 cubic. feet her displacement in fresh water would be equalto as many tons as 36) is contained times in 200,000, or 5,555.5 tons, and this would also equal her weight. To displace an equal amount