Beyond the first muttered warning to the little May party in the grove there was no thunder. The patter of the rain was a gentle lullaby to Amy, and at last she was wakened by a ray of sunlight playing upon her face, yet she still heard the soft fall of rain. With the elasticity of youth, she sprang up, feeling that the other cloud that had shadowed her thoughts might soon pass also. As she went singing down the stairway, Webb called from the front door: "Amy, look here! I was hoping you would come. See that rainbow." The cloud still hung heavily over the eastern mountains, while against it was a magnificent arch, and so distinctly defined that its feet appeared to rest on the two banks of the river. They watched it in silence until it faded away, and the whole scene, crowned with flowers and opening foliage tinted like blossoms of varied hues, was gemmed with crystals by the now unclouded sun, for the soft rain had clung to everything, from the loftiest tree-top to the tiniest spire of grass. Flame-like orioles were flashing through the perfumed air. Robins, with their heads lifted heavenward, were singing as rapturously as if they were saints rather than rollicking gormandizers. Every bird that had a voice was lifting it up in thanksgiving, but clear, sweet, and distinct above them all came the notes of the wood-thrush, with his Beethoven-like melody. "Have you no words for a scene like this, Webb?" she asked, at last. "It is beyond all words, Amy. It is one of nature's miracles. My wonder exceeds even my admiration, for the greater part of this infinite variety of beauty is created out of so few materials and by so simple yet mysterious a method that I can scarcely believe it, although I see it and know it. Men have always agreed to worship the genius which could achieve the most with the least. And yet the basis of nearly all we see is a microscopic cell endowed with essential powers. That large apple-tree yonder, whose buds are becoming so pink, started from one of these minute cells, and all the growth, beauty, and fruitfulness since attained were the result of the power of this one cell to add to itself myriads of like cells, which form the whole structure. It is cell adding cells that is transforming the world around us." He spoke earnestly, and almost as if he were thinking aloud, and he looked like one in the presence of a mystery that awed him. The hue of Amy's eyes deepened, and her face flushed in her quickened interest. Her own mind had been turning to kindred thoughts and questionings. She had passed beyond the period when a mind like hers could be satisfied with the mere surface of things, and Webb's direct approach to the very foundation principles of what she saw sent a thrill through all her nerves as an heroic deed would have done. "Can you not show me one of those cells with your microscope?" she asked, eagerly.