' Afl snow in summer, and as rain in harvest ; so honour is not seemly for a 

 fool." PEOV. xxvi. 



Because in a deep vessel containing 1 ice, and with heat applied at 

 the top, some portion of the water may be made to boil before the 

 ice, which lies a little under the surface, is melted. 



157. Why would you apply the heat at the top, in this 

 experiment ? 



Because in heating water it expands and rises. The boiling of 

 water is caused by the heated water ascending from the bottom, 

 and the colder water descending to occupy its place. If the heat 

 were not applied at the top, it would be distributed quickly by 

 convection, but not by conduction. 



158. Why are bottl?*^ of hot water, used as feet-warmers, 

 wrapped in flannel ? 



Because the flannel, being a bad conductor, allows the heat to 

 2)ass only gently fror* the bottle, and preserves the warmth for a 

 much longer time. ' 



159. Why are \>t rolls sent out by the lakers, wrapped 

 up in flannel ? 



Because the flarmel, being a bad conductor, does not carry off 

 rapidly the heat *f the rolls. 



160. Why M it said that snow Iceeps the earth warm ? 

 Because snc*jr is a bad conductor, and prevents the frosty air 



from depriving the earth of its warmth. 



161. WJiy are snow huts which the Esquimaux build 

 found to bo icarm? 



Because snow, "being a bad conductor, keeps in the internal heat 

 of the dwelling, and prevents the cold outer air from taking away 

 its warmth. 



162. Why is snoiv, being composed of congealed water 

 (and water being a better conductor than air), so good a non- 

 conductor ? 



Because in the process of congealation it is frozen into crys'taline 

 forms, which, being collected into a masa, form a woolly body, thoa 



