Last year I made not less than eighty such short excursions, each time with classes of about thirty-five. They were children of from seven to fourteen years of age. Without their hats, taking with them note-books, pencils, and knives, they passed with me to the street. The passers-by stopped to gaze at us, some with expressions of amusement, others of astonishment; approval sometimes, quite frequently the reverse. But I never once saw on the part of the children a consciousness of the mild sensation that they were creating. They went for a definite purpose, which was always accomplished. The children of the first and second years study nearly the same objects. Those of the third and fourth years review this general work, studying more thoroughly some one type. When they enter the fifth year, they have considerable causal knowledge of the familiar plants and animals, of the stones, and of the weather. But, what is more precious to them, they are sufficiently trained to be able to look at new objects with a truly "seeing eye." The course of study now requires general ideas of physiology, and, in consequences, the greater portion of their time for science is devoted to this subject. I am glad to be able to say, however, that it is not "School Physiology" which they study, but the guinea-pig and The Wandering Jew! In other words, I let them find out for themselves how and what the guinea-pig eats; how and what he expires and inspires; how and why he moves. Along with this they study also plant respiration, transpiration, assimilation, and reproduction, comparing these processes with those of animals, including themselves. The children's interest is aroused and their observation stimulated by the constant presence in the room with them of a mother guinea-pig and her child. Nevertheless, I have not hesitated to call in outside materials to help them to understand the work. A series of lessons on the lime carbonates, therefore, preceded the lessons on respiration; an elephant's tooth, which I happened to have, helped to explain the guinea-pig's molars; and a microscope and a frog's leg made real to them the circulation of the blood. In spite of the time required for the physiology, the fifth-year children have about thirty lessons on minerals; the sixth-year, the same number on plants; and the seventh-year, on animals; and it would be difficult to decide which of these subjects rouses their greatest enthusiasm. PRINCIPLES OF TAXATION.[6] BY THE LATE HON. DAVID A. WELLS. XX.--THE LAW OF THE DIFFUSION OF TAXES. PART I.