XXVI. Pressure transmitted in all Directions... XXVII. Pressure from the Weight of Liquids I. INTRODUCTION. 1. THE late Dr Whewell, congratulating a friend famous for his knowledge and ability on the birth of a son, said, "Young as he is he will learn more than you in the next twelve months." The remark may appear simple but it is striking from its truth; for it is curious to notice how soon a child placed under reasonably favourable circumstances gains the rudiments of all the science which the wisest men can teach. At a very early age the child begins to arrange and classify; he sees that some of the objects around him can move themselves, and that others cannot, suggesting the broad distinction between things which have life and things which have not life. Again, further subdivisions soon become clear; thus for example among living things he learns to bring together in his thoughts many that fly, and to call them by the name of birds. Even if he does not use a common name for a class of things which in some respects are like each other, he can hardly fail to notice the fact of likeness. Thus the water in which he is bathed, the milk he drinks, the ink he is forbidden to touch, must seem to him in some respects like each other, and different from the chairs and tables and toys of his nursery; though he has not learned to call the former fluids and the latter solids. 2. One of the most important words to be found in our language is Law. The original sense of the word is that of a rule or command which must be obeyed. Thus it is the duty of all people to obey the Law of the land; and it is the duty of children to obey the Law of their parents. In another sense the word Law is used to denote the unwavering constancy with which certain results will follow T. P. 1 |