পাতা:পদার্থবিদ্যাসার.djvu/২৫

14 - Tit. The gradual and slow increase and decrease of the sun's light, produced by the rays of light pass. ing through the atmosphere attached to the earth, without which we should pass instantly out of dark night into clear day, and ibe light would as suddenly leav £ t*s. Pu;. Woulii ibat 5. pr.judiciat? Th". Such a transition as the former would he dangerous to the eye, and the latter would often perplex and distress us: agains both these inconveniences God has wisely provided, by the twilight. Pitp. What occasions day and migbt ? Tut. The motion or revolution of the earth, on its axis, every twenty-sour hours: for to the inhabi. tants of that part of the earth which is opposite to the sun, it is day; and night to those on the other side. JPup. What occasions the d ifi:rence of the iength of days and nights Tut. The different positions of the earth with re. spect to the san. Pup. Is the diference of the length of days and nights the sausti in all countries 2 Tut. Nooie farther we advance from the equator, or middle of the earth, towards the poles, the difference in the lengths of the days and nights is the greater. 1'աք. "What is the difference in the length of days and nights in countries which lie immediately under the equator * , , , ... . . . Tat. Nothing; sor to countries sơ situated, they are always equal. a Pop what is the length of days and nights in: countries situated at the poles? . . . . . * * * *