Mr. Wilton, of course, did not know the exact state of Mr. Hume's mind; he did not know but that he came with a contentious spirit to bring up objections and propose hard questions; but he felt certain that, whatever his state of mind, the Spirit of God was bringing him to take this step. He had prayed for him; in prayer his soul had travailed in pain for him; and he felt that by way of the throne of grace he had obtained a hold upon Mr. Hume--that the Holy Spirit had bound a cord between them which could not be broken. He believed, therefore, that, whether he came penitent or angry, good would result from his coming. He gave him, therefore, a hearty welcome. "I am not only willing," he said, "but very glad, to have you come; and as I know that you have kept yourself informed of the latest phases of modern science, I hope we shall have your help in unfolding the subject which we are engaged in studying. I think you will be able to do us good." "Your kind welcome ought certainly to incline me to do anything which I can to help the interest of your study, but I only ask the privilege of sitting with your class as a silent listener." The Sunday-school opened as usual, and the classes entered upon their work. "You have come in, Mr. Hume, at just the proper point in the progress of our lessons," said Mr. Wilton. "We have been preparing the way by a brief review of the laws of heat. We have gone over the effects of heat; the conduction, radiation, and convection of heat; thermal reflection, absorption, and transmission; specific and latent heat. We have tried to form a conception of the existence and operations of heat according to the dynamic theory that heat is a mode of atomic motion. This review would have had little interest to you. We are now prepared to look at the goodness and wisdom of God in the management of heat. We are not trying to prove the existence of a Creator and Governor--we are only looking at the mighty and wise works of that God in whom we already believe. We shall find the works of God planned and wrought out with wondrous skill, and that wonderful skill is employed in the interest of goodness. God has planned and wrought for the benefit of his creatures. His wisdom and goodness are exhibited on the grandest scale and in gigantic proportions. This is all that is needed practically to demonstrate the existence of God. A good conscience does the rest. Being once assured that there is a Creator, a good conscience leaps to the conclusion that we ought to obey and serve him. Nay, the very work and existence of a conscience implies a divine Lawgiver and Ruler. To a good conscience a God is a necessity. But as we are not now attempting to show that there is a God, but to study his works, we will pass this point.