unseen, inconstant, and ungovernable wonder, the wind, to tell him the measure of its strength. Yet nothing can be more simple. He jumped against the wind; and by the length of his jump he could calculate the force of a gentle breeze, a brisk gale, or a tempest. Thus, even in his boyish sports, he was continually searching out the secrets of philosophy. </p> <p> Not far from his grandmother&rsquo;s residence there was a windmill which operated on a new plan. Isaac was in the habit of going thither frequently, and would spend whole hours in examining its various parts. While the mill was at rest he pried into its internal machinery. When its broad sails were set in motion by the wind, he watched the process by which the mill-stones were made to revolve and crush the grain that was put into the hopper. After gaining a thorough knowledge of its construction he was observed to be unusually busy with his tools. </p> <p> It was not long before his grandmother and all the neighborhood knew what Isaac had been about. He had constructed a model of the windmill. Though not so large, I suppose, as one of the box traps which boys set to catch squirrels, yet every part of the mill and is machinery was complete. Its little sails were neatly made of linen, and whirled round very swiftly when the mill was placed in a draught of air. Even a puff of wind from Isaac&rsquo;s mouth or from a pair of bellows was sufficient to set the sails in motion. And, what was most curious, if a handful of grains of wheat were put into the little hopper, they would soon be converted into snow-white flour. </p> <p> Isaac&rsquo;s playmates were enchanted with his new windmill. They thought that nothing so pretty and so wonderful had ever been seen in the whole world. </p> <p> &ldquo;But, Isaac,&rdquo; said one of them, &ldquo;you have forgotten one thing that belongs to a mill.&rdquo; </p> <p> &ldquo;What is that?&rdquo; asked Isaac; for he supposed that, from the roof of the mill to its foundation, he had forgotten nothing. </p> <p> &ldquo;Why, where is the miller?&rdquo; said his friend. </p> <p> &ldquo;That is true,&mdash;I must look out for one,&rdquo; said Isaac; and he set himself to consider how the deficiency should be supplied. </p> <p> He might easily have made the miniature figure of a man; but then it would not have been able to move about and perform the duties of a miller. As Captain Lemuel Gulliver had not yet discovered the island of Lilliput, Isaac did not know that there were little men in the world whose size was just suited to his windmill. It so happened, however, that a mouse had just been caught in the trap; and, as no other miller could be found, Mr.