He might have let the matter rest there but he did not. The occasion was too opportune a one to impress upon Polly the importance of not jumping at conclusions too quickly for him to refrain from borrowing an apt story from Selden about a young woman who, finding herself in the presence of some gentlemen, when they were examining what they called a Chinese shoe, and carrying on a dispute about it, put in her word, and said modestly, "Gentlemen, are you sure it is a Shoe? Should not that be settled first?" Then he passes to a highly edifying explanation of tidal movements in rivers, so simple that even a child, to say nothing of a bright-witted girl, could experience no difficulty in understanding it, and ends with the question: After writing 6 Folio Pages of Philosophy to a young Girl, is it necessary to finish such a Letter with a Compliment? Is not such a Letter of itself a Compliment? Does it not say, she has a Mind thirsty after Knowledge, and capable of receiving it; and that the most agreeable Things one can write to her are those that tend to the Improvement of her Understanding? With his next letter, he enclosed a paper containing his views on several points relating to the air and the evaporation of water, and informed Polly that he would shortly accompany her good mother again to Wanstead, when they could take a walk to some of Lord Tilney's ponds, and make a few experiments there that would explain the nature of tides more fully. "Adieu, my dear little Philosopher," he exclaims in another letter, after suggesting that thirsty unfortunates at sea might be greatly relieved by sitting in sea water, and declaring that wet clothes do not create colds, whatever damp may do. No one catches cold by bathing, he said, and no clothes can be wetter than water itself. In another letter, he makes some most readable observations upon the evaporation of rivers and the relations of colors to heat. The ignorant, he declared, suppose in some cases that a river loses itself by running underground, whereas in truth it has run up into the air. And, with reference to the interdependence of heat and color, he pursued this fresh train of ideas: