30. A reservoir is 2.80m long, 1.50m wide, and 1.25" deep.

How many liters will be required to fill .80 of it? 31. A man buys 1415h of wheat for $3.50 a hektoliter; but the measure used proves too small, the mistake amounted to 3' in every hektoliter. What was the quantity of wheat delivered to the purchaser, the cost, and the reduction which ought to be made to him on account of the error?

32. The dimensions of a tile are as follows: length 22cm width 11cm, thickness 55mm. Find the volume of the tile, and the number of tiles in a pile of 25cbm.

33. The measurement of a pile of wood shows that a ster could be filled from it 25.68 times. Give the volume of the pile in cubic meters, reckoning the length of the logs to be 1.15m.

NOTE. A ster is a frame, as represented in the diagram, one meter high and one meter between the upright posts. The ster may be filled with wood of any length, and the volume will be as many cubic meters as the sticks of wood are meters long.

34. A liter of air weighs 1.2738. How much does a cubic meter of air weigh?

35. A package of candles which weighs 4658 is sold at 28 cents. What is the price of a kilogram of candles? 36. How many times would 3.243 of water fill a liter? 37. Give the weight in kilograms of 43.4578ccm of pure

water.

38. The volume of an engine's axletree is .245cbm. Find its weight, the specific gravity of the iron being 7.8. 39. Calculate the volume of a gram of the following sub

stances: proof spirit, specific gravity .865; tin, specific gravity 7.291; lead, specific gravity 11.35; copper, specific gravity 8.85; silver, specific gravity 10.47; cork, specific gravity .240.

40. Olive oil costs 60 cents a kilogram. What is the price of a liter? The specific gravity of olive oil is .914. 41. Pure alcohol costs $1.87 a kilogram. What is the price of a liter? The specific gravity of alcohol is .792. 42. A man wants to build a shed large enough to hold 135st of wood; if the shed is to be 3m high and 5m wide, how long must it be?

43. In a country where fire-wood is cut 1.16m long, what height must the sides of the ster be to hold a cubic meter?

44. If a ster of cork costs $20.00, how much would 100kg cost, the cork weighing one quarter as much as water?

45. A liter of powder weighs 825o. What would be the volume of a charge for a gun if the charge weighed 5o? Calculate the volume in cubic centimeters.

46. Out of gold which weighs 19.362 times as much as water, sheets of gold-foil are made which are .010mm in thickness. What surface would 3o of gold cover?

47. Find the weight of an oak board 3.25m long, .31m wide, and .04m thick; the specific gravity of the oak being .808.

48. Find the weight of a bar of iron having the following dimensions: length 3.6m, width 6cm, thickness 2em; the specific gravity of the iron being 7.8.

49. How many lead balls each weighing 27% could be obtained by melting a mass of lead, cubic in form, the

edge measuring .356m, the specific gravity of the lead being 11.35?

50. Marble costs $30.95 a cubic meter, and the specific gravity of marble is 2.73. If a block of marble weighs 1260, what is its volume, and what is it worth?

51. Sea-water contains 28 parts, by weight, of salt in 1000. A liter of sea-water weighs 1.025kg. How many kilograms of salt could be obtained from 126.276842cbm of sea-water?

52. An empty cask weighs 17.06kg; when filled with water it weighs 275.8kg. How many liters does it hold? How many casks of this size would it require to receive the wine from a vat containing 3.008cbm?

53. It takes about 204.81 of wheat to sow

Cask.

a hektar. How many cubic meters would it take to

sow a square kilometer?

54. A piece of road 1km long and 7m wide is to be macad

amized; the macadamizing is to be 33cm deep; it costs 43 cents a cubic meter to prepare the stones. What will enough for the road cost?

55. A gasometer holds 28,000cbm of gas. How many jets would this gasometer feed, when each jet burns 1251 an hour, and is used 4 hours every evening?

56. The city of Venice is situated in the midst of a great lake of salt water, communicating with the sea, and all the rain-water is caught for the cisterns. Ordi

nary years the fall of rain in Venice is 82cm; the surface of the city, after the canals have been deducted, is 520ha; reckoning the population at 115,530, how many liters a day of rain-water could each inhabitant have?

57. Find the weight of a bar of iron 5.35m long, 4.56cm thick, and 3.54cm wide. Find, also, the width of an oak beam 4.30m long, 9.12cm thick, which has the same weight. The specific gravity of the oak to be reckoned at 1.026, that of the iron 7.788.

58. Give the specific gravity and volume of a body weighing 35kg in air and 30kg in water.

59. A ster of piled oak wood weighs 425g; the specific gravity of the wood is .74. What is the volume occupied by the spaces between the logs? For how much must 100kg of separate sticks be sold in order to bring the same amount as when sold by the ster; a ster selling for $2.20?

60. Wrought iron sells for $7.00 per 100kg. A bar of iron 4.5cm wide, 3.3cm thick costs $5.08; what is its length, reckoning the specific gravity of the iron at 7.4? 61. Experiment shows that water weighs 770 times as much as air; and the specific gravity of mercury, in comparison with water, is 13.6. How many liters of air will it take to weigh as much as a liter of mercury? 62. A mass of lead weighing 753kg is made into sheets .1mm thick. Calculate, in square meters, the surface which can be covered by the sheets thus obtained. The specific gravity of the lead is 11.3.

63. A rectangular sheet of tin of uniform thickness is 85cm wide, 1.35m long; it weighs 2688. What is its thickness, reckoning the specific gravity of tin at 7.3?

64. The fine coal which collects about the shafts of the mines and in the coal-yards, was for a long time.

wasted, because it could not be burned in stoves and grates. Now, this dust is mixed with tar in the proportion of 92kg of dust and 8kg of tar; the mixture is heated, and afterwards pressed in rectangular moulds of 14.75cm, 18.5cm, and 29cm; each one of these blocks weighs 10kg, they are sold at $3.00 a ton, and make excellent fuel for heating steam boilers. Give the specific gravity of this fuel; also, the sum which would be realized in thus utilizing 800,000 of coal dust, the cost of tar, mixing, etc., being $.50 a ton? 65. A bar of iron a millimeter square on the end will break under a tension of 30kg. Find the length at which a suspended bar of iron will break from its own weight, the specific gravity of the iron being 7.8?

66. Fifty-three kilograms of starch are obtained from 100kg of wheat. A hektar of land produces 1363' of wheat; a hektoliter of wheat weighs 78kg. If the wheat harvested from a field measuring 2ha and 339m is taken to a starch factory, how much starch will be made from it?

67. A gardener wishes to provide glass for his hot-beds. The beds cover 2.65a; the panes will cover .75 of the whole surface, the rest being taken up by the frames and alleys. First, find how many panes measuring 45cm by 37cm it will take to cover the beds; then find the price of the glass, at a cost of 95 cents a square meter.

63. A jar full of water weighs 1.325kg; filled with mercury

it weighs 12.540kg. What is the capacity of the jar, and its weight? The specific gravity of the mercury is 13.59.

69. A hektoliter of rape-seed weighs 63kg, and 321 of oil can be extracted from it. How many kilograms of the seed will it take to make a hektoliter of oil?