154. Why do we see blocks of ice wrapped in thick flannel in summer time?
Because the flannel, being a non-conductor, prevents the external heat from dissolving the ice.
Flannel wrapped around a warm body keeps in its heat; and wrapped around a cold body, prevents heat from passing into it.
155. How do we know that air is not a good conductor of heat?
Because, in still air, heat would travel to a given point much more rapidly, and in greater intensity, through even an indifferent solid conductor, than it would through the air.
156. How do we know that water is not a good conductor of heat?
Because in a deep vessel containing 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.
"As snow in summer, and as rain in harvest; so honour is not seemly for a fool."—Prov. xxvi.