Curiosities of Heat

ust now examine the arrangement for softening the rigors of winter and toning down the heat of summer. The general principle is that in summer the earth receives an excess of heat, while

rong, I cannot tell. I should think heat might be carried f

eat which seem to you to operate the same in the

heat, and another is the evaporation o

d sea slowly radiate their heat. We can hardly over-estimate the effect of this alternate absorption and radiation of heat. So great is the effect of this stored up heat that the sea and the great lakes never freeze even in the coldest winter weather, except in the polar regions, and the temperature must fall far below freezing and continue for a long time below the freezing point before the earth begins to freeze. The great bodies of water, remaining always at a temperature above thirty-two degrees, are especially important in warming the wintry air. In the coldest weather they seem like steaming caldrons throwing up their warm vapor. It is the absorption and radiation of heat alone which prevent the temperature of the at

e share. But water stands chief, and performs the largest service. Its high specific heat enables it

and a half feet of ice water. If the mean winter temperature at the same place be thirty-six degrees, more than three-fourths of this vapor must be condensed and give out its latent heat to warm the air. It is not to be supposed that the full amount of vapor which can support itself does commonly exist, but the difference between the average amount of vapor in summer and in winter must be very great. I suppose this difference often amounts to four or six inches of water. If we suppose it to be four inches, an amount of heat is transferred from summer to winter sufficient to boil twenty-two inches of ice water. In estimating the effect of this we must consider that this heat is not given out gradually and regularly for three months, but when

hich heat treasured up in summer is made available for

In the process of crystallization one hundred a

y pound of water frozen in the wet earth, every pound of water frozen as snow or sleet in the air, gives out as much heat as would boil an

I asked him why he put tubs of water in his cellar, but he could not tell me, only he said that

tubs of water set in a cell

r begins to freeze it begins

heat which the water loses the air of the cellar gains. And then, as you said, as soon as the water begins to freeze latent heat begins to become sensible. Every pound

n't k

event vegetables from freezing; the water begins to freeze at thirty-two degrees, while potatoes and turnips may be cooled a little lower than thirty-two degrees without harm. In this manner the buds of trees are sometimes warmed and protected by the coating of ice which forms ar

that snow contains heat, that 'it would be a blessed thing for the poor

s of heat are evolved, and in the congelation one hundred and forty degrees-an amount of heat which would boil three feet of cold spring water. In every square mile there are 27,878,400 square feet, and a square mile of water three feet in depth would contain 83,625,200 cubic feet. The production of such a snow-storm sets free for every square mile of surface heat which would boil more than 80,000,000 of cubic feet of spring water. Such a storm sometimes extends over a region of country a thousand miles square, that is, over a million of square miles. In the production of one such storm-a very heavy and extensive storm, I have supposed-heat is generated which would boil eighty millions of millions (80,000,000,000,000) of cubic feet of spring water-an amount altogether too vast for our comprehension. To accomplish this result by combustion would require more than 500,000,000 of tons of anthracite coal-an amount at least three times as great as the yearly product of all the coal-mines of the world. And this is but one heavy storm. The amount of rainfall in the United States may be thirty-six inches or forty or forty-five inches. Supposing the average rainfall of the whole earth to b

nded you that water presents a marked peculiarity, and promised to speak of it more fully. This is the place for us to look

and cold contracts

new stratum be brought to the surface; that in turn would be cooled and sink, and thus the cooling process would go on with the utmost rapidity till the whole body of water should be reduced to the freezing temperature. Then congelation would begin, and the first particles of ice formed would sink to the bottom, and as fast as the water became frozen at the top the ice would sink. In this manner a solid body of ice would be formed at the bottom of our lakes and rivers, while the surface would remain unfrozen in contact with the cold air till the whole body of water became a compact mass of ice. Great lakes turned to solid ice would not be thawed during the whole of the summer, for the water warmed from the top would not sink, but would form a warm stratum of water upon the surface, while, below, the

ontraction of water," asked Mr. Hume, "as a real

minant, and throws the atoms into new positions and new relationships. To this new arrangement of atoms is due the expansion in freezing. Ice contracts and expands by cold and heat the sam

as is conferred upon winter. The summer is cooled as much as winter is warmed. The formation of vapor is a cooling process. Water is prevented from rising above the boiling point by the formation of vapor.

p in store to-day to be expended at any future time when needed. The transfer is a transfer not in space, but in time. We must hereafter examine those arrangements by which heat is transported through space. Some of these arrangements exert an influence upon day and night and upon summer and winter, and thus throw further light upon the subjects already discussed. Already more than once topics have been su

se outward things are wonderful and beautiful for the setting, but the gem, the royal precious stone, the Koh-i-noor, the 'mountain of light,' for which the setting was made, is the true knowledge of the true God and of his Son Jesus Christ. During the past few weeks you have heard others asking, 'What shall we do

a desire that my friends should repent and believe in Jesus. I think the love of Christ constrains me. I have not felt before that my work was very importan

u tried to do

nd especially for Ansel and Peter. And then I felt t

o anxious for you? Are you contented to live 'having no hope and without God in the wo

ve been talking together about being Ch

tell them what they must do to be saved. They wished to go on with these lessons, but t

t I know that there must needs be 'line upon line.' If Ansel and Peter wish it, I will devote a sermon to the subject, and make it as

t, and I am sure that you will have a great man

ot pray for Mr. Hume al

with him. I have tried to pray for him a doub

This pious young man was afraid to come to him lest he should meet the scornful arguments and cold derision of a proud unbeliever. He felt humb

ng Christ and the Holy Spirit as Sam

to me freely. I think he need not be afraid of me now. I also ho

aching. 'When he, the Spirit of truth, is come,' said Jesus, 'he will lead you into all truth.' This was fulfilled pre-eminently, I suppose, in the inspired men who laid the foundatio

ou the outline of the sermon if