Again, if in the above ship, where the speed is 8.5 knots for a daily consumption of 30 tons, it is found that three days' coal are left at that speed when 1000 miles from port, to what speed must she be reduced to reach port? Consumption varies as square of speed multiplied by distance.

It is evident that the more deeply a ship is laden the more power is required to drive her through the water at the same speed, and it is found that the consumption or I.H.P. varies as the 3rd power of the displacement, that is as the cube root of the square of the displacement. Thus if in a ship of 5000 tons displacement, 4000 tons are taken on at one port, and it is found that the consumption per day is 50 tons to drive her at a speed of 9 knots, what would the consumption be per day when the 1000 tons are taken on at another port to make the same speed?

1. Find net freight on 2400 tons at 17s. 6d. per ton, after allowing 6% loading commission and 8% primage.

2. Find the net freight of 5600 tons at 6 dollars per ton, allowing 5% loading commission and 7 % primage, exchange being 4-85 dollars to £1.

3. Calculate net freight on 2700 tons at 22s. 6d. per ton, if primage is 71% and loading commission 3 %.

4. Convert £6836 10s. to dollars if £1 = 4.66 dollars. Convert 567832.5 francs to £'s. if £1 = 28·4 francs.

5. Wine costs 3.5 francs per litre, how much is this per gallon. The price of meat is 4 francs per kilogramme, how many pence per lb. ?

6. Find displacement of a ship in tons whose dimensions are: Length 465 ft., breadth 50 ft., draught 28 ft., coefficient of fineness 84.

7. Taking the height of a mercurial barometer to be 30 ins. when a water barometer reads 34 ft., find S.G. of mercury.

8. The sectional area at load water-level is 5600 sq. ft., how much will 320 tons of bunkers sink her?

9. Find coefficient of displacement of a liner 525 ft. long by 51 ft. broad by 25 ft. draught, her displacement being 15,300 tons.

10. A lifeboat is 24 ft. long, by 7 ft. 3 ins. wide, and 3 ft. 6 ins. deep: how many people will it carry, and what air-tight space must be allowed? N.B.-Use 6 as multiplier for finding cubical contents, and allow 10 cub. ft. per person, of which 1 cub. ft. must be air-tight.

11. How long must a bunker be made to contain 250 tons coal, allowing 42 cub. ft. to the ton, beam of ship 56 ft., height 'tween decks 6 ft. 6 ins.

12. The length of a rectangular field is to its breadth as 3 to 2, and its area is 11,094 sq. metres. Find the cost of surrounding it with a fence at 2.25 francs per metre length of boundary.

13. If 648 boxes are stowed close together on board a ship, find the total cost of freightage at 1s. 2d. per cub. yard, when each box measures 4 ft. long, 3 ft. wide, and 24 ft. deep.

14. A rectangular tank 8 ft. long and 7 ft. wide holds when full 6 tons of water find its depth.

15. If gold is worth 3 francs 10 centimes per gramme, find its value per ounce in English money, taking a franc as equal to 9 d., and a gramme as 15.43 grains.

16. How many tons of coal will a bunker 10 ft. 3 ins. deep, 42 ft. 6 ins. long, and breadth at two ends 8 ft. 6 ins., and in middle 10 ft., hold?

17. How many persons will a lifeboat hold whose length is 22 ft. 6 ins., breadth 6 ft. 6 ins., inside depth 3 ft. 6 ins., and what number of cubic feet of air-tight space should it contain?

18. A supposed cubical iceberg is 100 feet above level of sea, S.G. of ice 921, sea water 1.026: find total height of berg.

19. If the displacement of a ship is 6800 tons, her length 340 ft., breadth 35 ft., and draught 22 ft., find coefficient of fineness.

20. If 150 tons of bunker sink a ship 5 ins., find her area at that water level.

21. Taking S.G. of iron as 7·7, find weight in pounds of a plate 20′ × 2′ × 1".

22. Length of ship 525 ft., beam 55 ft., coefficient of fineness 9: how many tons per "inch" immersion?

23. Find approx. the daily consumption in a vessel of 5000 I.H.P.

24. Find safe working loads for chains of in., 1 in., and in. diameter.

25. When chains are weakened by having been in use for a time, how is strength restored?

26. Find safe working strain of manilla ropes of 3 circumference.

27. Find the safe working strain of wires 1 in., 2 ference.

ins., 5 ins., and 63 ins.

ins., and 5 ins. circum

28. How many parts of a 3-in. rope will be equal in strength to a 6-in. rope?

29. What weight will a 34-in. rope hang, when rove as a tackle having 6 parts at the travelling block?

30. What weight will a 24-in. wire raise, using a double purchase?

31. What size rope or wire would you use to get out a 15-ton weight with a fourfold purchase and leading block?

32. What size rope and wire would be required to take out a 14-ton weight with a treble block?

33. If the breaking strain of a 2-in. chain is 72 tons, what is it of a 3-in. chain ?

34. Mercury is 10,574 times as heavy as air, the S.G. of mercury is 13.597 find the weight in grains of 1 cub. ft. of air.

35. From Glazebrook's experiments the S.G. of air at 15° C. and 760 mm. pressure when saturated was 0012. Find weight in grains of 1 cub. ft. of this air.

36. Taking the composition of air to be 77 % of nitrogen, 21 % of oxygen, and the remainder carbonic acid gas, and Ganot's estimates that 1 litre of nitrogen at 0° C. and 760 mm. weighs 1.2561 grammes, of oxygen 1·4298 grammes, of carbonic acid 1.9774 grammes, find weight in grains of 1 cub. ft.

37. At 32° F. the velocity of sound is 1090 ft. per second, and the increase is at the rate of 10 ft. per second for each 9° F. rise in temperature.

You see the flash of a gun, and 6 seconds after hear the report, temperature 68° F. how far away is the gun?

38. If the velocity of light be reckoned at 299,860 kilometres per sec., how many miles per sec. is this?

39. The pitch of a propeller is 15 ft., and it makes 60 revolutions per minute, allowing 5 % slip: find actual speed.

40. The pitch of a propeller is 16 ft., revolutions per minute 57, and time for measured mile is 7 minutes: find slip %.

41. The speed on the trials is 9-5 knots, propeller pitch 19 ft., revolutions per minute 56, find slip %.

42. For a speed of 10 knots, the daily consumption is 25 tons: what would the consumption be for speeds of 12 knots and 8 knots ?

43. The daily consumption for a speed of 19 knots is 150 tons: what amount would be necessary for speeds of 21 and 15 knots ?

44. For a daily consumption of 55 tons, the speed is 13 knots: what speed would be developed on consumption of 30 and 80 tons per day?

45. On a daily consumption of 84 tons, the speed is 15 knots: what would

it be for consumptions of 2.5 and 5 tons per hour?

46. In a ship 163 tons of fuel are consumed per hour for a speed of 24 knots: how many tons will be required for a voyage of 4 days if the speed is increased 1 knot?

47. The total consumption for a certain distance at 9 knots is 240 tons: what would it be for same distance if speed is increased to 13.5 knots ?

48. A ship steams 10 knots on 23 tons daily: how much coal will be required to steam 3036 miles in 11 days, and have 100 tons in reserve?

49. At 60 revolutions per minute the I.H.P. developed was 3500, what would the I.H.P. be when revolutions were increased to 75 per minute? How much coal per day is consumed under the two conditions?

50. For 1800 miles at 10 knots, the consumption is 500 tons: how much will be required for 2500 miles at 12 knots ?

51. The consumption per day for a speed of 12 knots is found to have been 51 tons. There are 150 tons of coal left in bunkers, and 1152 miles to port, speed is reduced to 10 knots, how much will there be at the end of the voyage?

52. On a daily consumption of 80 tons, the vessel makes 15 knots; with only one day's coal left at this speed and 1000 miles to go, at what speed must she proceed to reach port?

53. There are 20 days' coal on board, when steaming at 9 knots on 35 tons per day, and 100 tons reserve. When 12 days out, owing to bad weather, it is found that 45 tons daily have been consumed: at what speed must she proceed to arrive with 50 tons in bunkers?

54. A vessel with a displacement of 3000 tons consumes 25 tons daily : what would consumption be at displacement of 2000 and 4000 tons?

55. A ship of 10,800 tons displacement burns 100 tons of coal daily, for a speed of 13.5 knots: what would be the effect on the consumption of taking in 300 tons extra cargo, and increasing speed knot?

56. A vessel of 8000 tons displacement has 7000 tons on board at one port, and develops a speed of 12 knots on 50 tons per day: what consump tion will she have to make a speed of 13 knots, when the extra 1000 tons is taken in ?