"We might look at other appliances for transferring heat from summer to winter, but they belong in principle to another department. We have now looked at some of the means for transferring heat in time. The heat is treasured up at the heated noonday, to be brought out for use during the cool hours of night; it is garnered from the excessive heats of summer to supply the deficiencies of winter. It is laid up 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 suggested and their full consideration put off till some more fitting time. In our next lesson we must begin the examination of these new principles. We have before spoken of the vicissitudes of days and seasons and years. We shall now have to do with the vicissitudes of zones and lands and seas, of deserts and mountain ranges. The elements become vaster, the stage is broader, and the movements more sublime. "I am glad that you are so well interested in these great and beautiful works of God's wisdom and power, but I hope that you do not forget that the crucified Christ is pre-eminently the power of God and the wisdom of God. These natural works are but the husk of which salvation from sin by Christ is the kernel. These 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 to be saved?' I should be greatly guilty if I allowed you to think earth, air, and sea, with all their silent and solemn movements, more important than our spiritual attitude toward God the Father and Christ the Saviour. Are you, Samuel, in your interest in studying Nature, forgetting Christ and the souls of men?" "I hope not, and I think not. During the three years since my baptism I have never felt so much my obligation to Christ as now. I never felt before so deep 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 important; I have been expecting to work more earnestly by and by; but lately I have felt that Christ gives me something to do now for which he holds me responsible." "What have you tried to do for Christ?" "I have been praying for some of my young friends, and especially for Ansel and Peter. And then I felt that I must talk with them as well as pray for them."