IN DESCRIPTIVE ASTRONOMY. Ill 



4. In wJiat part of the ski/ do you always look for the 

 planets ? 



Within the limits of the Zodiac. A few of the asteroids 

 only pass outside this belt of the heavens. 



.5. Show how it was impossible for the darkness that 

 occurred at the time of the Crucifixion of Christ to have 

 been caused by an eclipse of the sun. 



The Feast of the Passover took place at full moon. "With 

 the Jews, a month began when the new moon was seen. Per- 

 sons were appointed to watch, about the time it was expected, 

 on the tops of mountains. As soon as they saw its light, they 

 gave notice by sounding trumpets and building fires." Kevin's 

 Biblical Antiquities. 



0. Is there any danger of a collision between the earth 



and a comet ? 



(See Astronomy, p 192.) 



A collision between the earth and a comet must be a rare 

 occurrence. Babinet computed that one would strike the earth, 

 on the average, every 15,000,000 years. There are certainly, 

 however, comets whose orbits cross the earth's path, and if we 

 should happen to reach the crossing at the same time with one 

 of them, there would be a collision. We should probably never 

 know of the event unless we were watching for it. 



7. Hoiv are aerolites distinguished ? 



(See Astronomy, pp. 177, 178.) 



Aerolites, when found, generally have an exterior crust of 

 fused material, presenting a glossy, pitch-like appearance. An 

 analysis of the interior commonly presents a combination of 

 elements that is so characteristic as to identify the body as an 

 aerolite even when not seen to fall. Large masses have been 

 found in Northern Mexico which are thus known to be of me- 

 teoric origin. 



" The meteoric stones may be divided into two distinct 

 groups meteoric iron, and meteoric stones proper. 



" 1. Meteoric iron is an alloy of iron and nickel, containing 

 about 10 per cent, of nickel, and small quantities of cobalt, 



