Sulphur, a well known simple substance, found in combination with metals and otherwise. See page 19. Sulphurous and Sulphuric acids are formed through the affinity of sulphur for oxygen. Sulphur in combination with another substance, forms a sulphuret; sulphurous and sulphuric acids form in combination Sulphites and Sulphates. Synthesis, the composition of any body from its original parts. Syringe Condensing, an instrument used for the purpose of charging the ball of an air gun. See page 38.

Telescope, an instrument for viewing distant bodies. By a combination of lenses the object is seen under a larger angle than with the naked eye, and its apparent magnitude proportionately increased. Tellurium, a metal discovered in the year 1798. It will form combinations with various bodies, but it has not yet been used except for experiments.

Thermometer, an instrument for discovering the temperature of the air. Tin, a well known white metal. See page 79.

Titanium, a metal somewhat like copper, discovered in the year 1796. It is of no particular use.

Trumpet, Speaking and Hearing. See page 50.

Tungsten, a very heavy metal, when pure it is extremely hard and brilliant. It is of very little use.

Uranium, a metal discovered in the year 1786. It is hard and brittle, but it has been found in very small quantities, and is of no particular use.

Vacuum, a space void of matter.

Vision. See page 27.

Voltaic Electricity, or "Galvanism." See page 62.

Water. For the various kinds of this fluid, see page 40.

Wind, air in motion. See page 55.

Zero, a term applied to a certain point in the thermometer; in Fahren. heit's thermometer it is placed at 32o below the freezing point. In Reaumur's, as also in the French centigrade thermometer, it is placed at the freezing point.

Zinc, a well known metal. See page 81.

223

QUESTIONS

ON

THE SCIENTIFIC READINGS.

ATTRACTION.

1. What is meant by Attraction?

2. Into how many kinds may attraction be divided, and explain them?

3. How many kinds of attraction of gravitation are there, and what are they?

4. At what part of the earth is the power of Gravity the greatest?

5. Why would a piece of metal as a sovereign, and a feather fall with like velocity in an exhausted receiver?

6. In what ratio does the power of gravity increase and decrease?

7. What is that kind of gravitation by which the heavenly bodies are retained in their orbits?

8. In what proportionate degree do the Primary planets act upon their Secondaries?

9. What is the rate of descent of a falling body, near the earth's surface?

10. Through what principle is it that a glass ruler, or a stick of sealingwax, when rubbed, will attract light bodies?

11. By what power is it that the atoms of bodies cohere? 12. Were the ancients acquainted with magnetic attraction?

13. Why or through what principle does water ascend to the branches of trees by means of their roots?

14. To what cause is the cohesion of bodies attributed? 15. What is the opinion of Sir Richard Phillips in regard to capillary attraction?

16. What is the chief antagonist to cohesion?

17. What kind of attraction is that when the force acts on atoms of the same species?

18. When the force of attraction acts on atoms of different substances, what is it then termed?

19. To what is the spherical shape of drops of quicksilver attributed?

20. How many kinds of chemical attractions are there? 21. How do bodies generally combine?

22. When a chemical combination has been effected, can the bodies combined be separated by mechanical means?

23. What is simple and what compound affinity, and give an example of each?

24. What is the chief principle of action in chemical combinations?

25. How far will a body fall near the earth's surface during the space of five seconds, of seven seconds, and of

ten seconds?

26. What will be the quantity of descent of a body during the third second; the sixth second and the ninth second of its fall?

27. How long would a body take to fall through a space of 500 feet, of 1000 feet, and of 1500 feet?

CALORIC, HEAT, FIRE.

28. What would have been the state of man without fire? 29. Is fire a real substance?

30. What is Fire ?

31. What is Heat?

32. What is meant by the term Caloric?

33. What effect do we produce on a heated body by touching it, and what on a cold body?

34. By what term are those bodies distinguished which transmit caloric readily?

35. Which are the best and which the worst conductors of caloric?

36. Why does the quicksilver or alcohol rise in the Thermometer in hot weather?

37. What do the thermometers contain which are used in the higher latitudes?

38. What is the natural state of bodies?

39. What is meant by atomic motion?

40. Does water, when converted into ice, take up more or less space than when in its fluid state?

41. At what angle do the crystals of frozen water form? 42. When water is converted into steam, what striking power does it acquire?

43. What is the chief source or cause of caloric?

44. Into how many kinds is caloric divided, which are they, and explain them?

45. Which colour radiates heat most?

46. Which colour absorbs the rays of light, and which reflects them most?

47. What would be the effect produced on a vessel scratched, as it regards the radiation of heat?

48. What is it said that the cause which produces the sensation of heat resembles ?

49. What is the shape of those mirrors used to concentrate the sun's heat?

50. What effect has a convex lens on the sun's heat? 51. What is the difference between a lens and a mirror? 52. By what means did Archimedes set fire to the Roman fleet?

53. In what ratio were the sun's rays condensed by Mr. Parker's burning-glass?

54. What person, in the reign of Elizabeth, ignited bodies by a combination of plane mirrors?

55. Describe Buffon's combination of plane mirrors, and the effect produced?

56. What was the effect produced by Mr. Parker's burning-glass?

57. What are the various means by which caloric is produced?

58. How is caloric produced by combustion?

59. By what means is the strongest heat produced by combustion?

60. How is heat produced by Percussion; how by Friction?

61. Explain how fire is produced by the collision of the flint and steel.

62. To what does oxygen owe its gaseous state?

63. How do savages procure fire?

64. What is the general rule for the production of heat by chemical mixture?

65. If two ounces of sulphuric acid be mixed with eight ounces of cold water, what will be the quantity of the mixture?

66. Why is heat evolved in slaking lime?

67. By what means has the strongest heat known been produced; and what has been the effect resulting therefrom?

68. With what force will steam, at 590°, press on a space of two inches square, of three inches, and of four inches square?

69. If a mirror of four feet in diameter produce a focus of half an inch in diameter, in what ratio will the heat be increased?

70. If a convex lens of one foot in diameter produce a focus of a quarter of an inch in diameter, in what ratio will the sun's rays be condensed?

COMBUSTION.

71. Define Combustion.

72. Which are simple, and which compound combustibles?

73. Which is the only simple combustible that nature offers pure and in abundance?

74. What substance is that which so much abounds in the different kingdoms of nature?

75. What quantity of sulphur has been imported annually, for the purpose of making gunpowder and sulphuric acid?