First Sentence

""For though most men are contented only to see a river as it runs by them, and talk of the changes in it as they happen; when it is troubled, or when clear; when it drowns the country in a flood, or forsakes it in a drought: yet he that would know the nature of the water, and the causes of those accidents (so as to guess at their continuance or return), must find out its source, and observe with what strength it rises, what length it runs, and how many small streams fall in, and feed it to such a height, as make it either delightful or terrible to the eye, and useful or dangerous to the country about it.""