184 NATUBE-STUDY LESSONS. 



i6. As the shadow is shortening, observe the time at 



which the sun rises or sets for a number of successive 



days. 



Make a quadrant of a circle a foot in radius, and mark the number of 

 degrees on the circumference from o to 90. Place the centre of the circle 

 at the point reached by the shadow on the "shadow-board," and the cir- 

 cumference towards the upright part with the point marked o on the upper 

 edge of the horizontal board, and find the number of degrees the sun is 

 above the horizon. 



17. On what day is the sun highest in the heavens at 

 noon? 



18. On what day is the sun lowest in the heavens aC 

 noon? 



The height of the sun in degrees above the horizon at 12 m. is its meri- 

 dian altitude. 



19. What is the sun's meridian altitude on June 21,'it ? 

 on May 21st? on Jan. 21st? etc. 



20. What do we get from the sun ? 



21. («) Discover which is generally the hottest mof^th 



of the year. 

 (b) Why is it not the hottest time of the yeaf 

 about the 2 1st of June? 



22. (a) In an east and west ravine, on which slope are 



the earliest flowers of the spring to be found .' 

 (J}) Account for the difference in the growth of 

 the vegetation on the two slopes. 



23. («) In a north and south ravine, on which slope 



are the earliest flowers of the spring to be 

 found ? 

 (J)) Why should vegetation grow earlier on one 

 slope than on the other? 



24. Give two reasons why the weather grows warmer 

 from March till June and colder from August till 

 December. 



