the body of the sun and moon is visible before they rise and after they set.

Solution. This is true at any place of the earth, and arises from refraction, which raises all the heavenly bodies, and makes them appear higher at all times than they are, but more so at rising and setting, which sometimes extends to 10 minutes, a sufficient length of time to make them visible some time before they begin to rise and after they set.

19. There is a certain circle on the earth, on which if a man walk any distance, his head will pass over more space than his feet, and his feet will uniformly meet more resistance than his head.

Solution. It is evident, from the globular form of the earth, that wherever a person walks, it must be on a circle, and as his head is farther from the centre of the circle, (that is, the centre of the earth,) it must pass through more space; and as the atmosphere is denser at the surface of the earth than above it, his feet must meet greater resistance from it.

20. There is a large town in Britain, that is neither in Scotland nor England, and the air is of that peculiar quality, that the moon appears always most enlightened when she is absolutely least so, and least enlightened when she is most so.

Solution. This holds good, with respect to the moon, in every town and place on the earth, because

when the moon is full she appears most enlightened, but it is known she is least so; as she is then all the breadth of her orbit, which is 480,000 miles, farther from the sun than at the change, when she seems least enlightened. With respect to the town being in neither country, may be said of Berwick-uponTweed, which is partly in England and partly in Scotland, the river Tweed, which separates the countries, passing through it.

21. There are certain places in the vicinity of London, not forty-feet broad, where a man might travel 100 miles, but in such a situation, that one of his feet must pass through more space than the other.

Solution. This may be understood of not only places near London, but any where on a circle; a person may go round it to any length of space, and it is evident, that the foot next to the outer side must go faster than the one next the centre, and therefore pass through a longer extent of space.

22. There is a spacious plain near Seringapatam, in the Hither Peninsula of the East Indies, where an army of 90,000 men could be drawn up in battle array; but it is of that nature, that if they were drawn up, yet it would be impossible for any two of them to stand (naturally) parallel to one another.

Solution. The same may be said of any plain, or

part of the earth, as, from its globular form objects placed perpendicular to the plane of the horizon cannot be parallel to one another, their heads being farther apart than their feet; therefore the walls of a house, the pillars of an entry, &c. are not parallel to each other; and may be compared to the spokes in the nave of a wheel.

23. There is a place of the earth, where the most ponderous weight would support itself, without the assistance of any substance whatever.

Solution. This place must be at the centre of the earth, where gravity ceases. Suppose a passage made from one side of the earth, through the centre, to the other side, and a weight dropped through it, after several vibrations, it would settle at the centre, and hang suspended without any support, there being no attraction to draw it away.

24. There are certain places on the earth, where, if men were placed at each of them, those at some of the situations would pass through thousands of miles more than those at the other places, in one day, without their leaving the position that they were placed in.

Solution. Some of them may be placed at or near the poles, others at or near to the equator, then those near the poles would experience some thousands of miles less of the diurnal motion of the earth than those near the equator.-NOTE. Objects on the equator are

carried 25,008 miles in a day by the earth's diurnal motion, while at the poles they are only affected by the earth's motion in its orbit.

THE APPLICATION, BY QUESTION AND ANSWER, TENDING ΤΟ PROMOTE A PRACTICAL REVIEW OF THE WHOLE.

CHAP. XI.

1. QUESTIONS RELATING

ΤΟ THE TERRESTRIAL

GLOBE.

1. Required which of the poles is raised, and how much, when the globe is rectified for the Cape of Good Hope? Answer, the south pole is clevated 34° 26'.

2. What is the latitude and longitude of Lima, in South America? Answer, 12° 1' S. latitude and 76° 40′ W. longitude.

3. Given a place in latitude 55° 41' N. and longitude 12° 46′ E.; required the place? Answer, Copenhagen, in Denmark.

4. Required what places have the same latitude as the city of Naples, in Italy?

Turn the globe quite round, and all the places that

pass under 40° 51′ N. lat. have the same latitude as Naples.

5. Given Jeddo, the capital of the empire of Japan; required its antoci? Answer, at lat. 36° 10' S. and lon. 139° 30′ E. in the Pacific Ocean.

6. In what latitude and longitude are the periœci of Bristol? Answer, 51° 29′ N. lat. and 177° 24' E. lon. amongst the Aleouskie Islands, N. Pacific Ocean.

7. Required the antipodes of Cape Horn, the south point of America? Answer, at 55° 58′ N. lat. and 112° 40′ E. lon. in Siberia.

8. What is the difference of latitude between Quebec in Canada, and Moscow in Russia? Answer, 8° 50′.

9. Required the difference of longitude between Dublin and Cape Comorin, the south point of the Hither Peninsula in the East Indies? Answer, 84° 53′.

10. Given two places on the same meridian, one in 20° N. lat. and the other in 30° S. lat. ; required their distance in miles English? Answer, 3475 miles.

11. Required the distance between two places in lat. 20° N. or S., one place being in 2° 15′ W. and the other 15° 45′ E. lon.? Answer, 1175 English miles, 10142 geographical miles.

12. What is the greatest distance that any two places can be apart on the earth? Answer, 180° geographical miles 12,510 English miles.

10800