that belt stationary in its position; nor, 4thly, is it uniform in its breadth.  It will thence be easily understood, even by a person who has never quitted one of the midland counties in England, and to whom the ocean is an unseen wonder, that a new-comer to the tropical regions, his head loaded with these false views, will be very apt to mistake his own ignorance for the caprice of Nature, and perhaps call out, as I once heard a man do, in all the agony of impatience caused by a protracted head-wind,—­“Now, this is really scandalous usage of the clerk of the weather-office!” The scandal, however, lay not so much with the clerk’s usage as with his own limited knowledge; for if, at the very time of his imprecation, instead of abusing the foul wind, and keeping his yards braced sharp up, and making his sails stand like a board, the grumbler had known how to take advantage of it, and had kept away two or three points, set his fore-topmast studding-sail, and flanked across or through the breeze which he had in vain tried to beat against, he might not only have saved his temper, but have made his passage in half the time.

I am not sure that, in the whole range of this extensive subject, there could be picked out an instance more in point to what has just been said, than these interesting phenomena of the Trade-winds.  To sailors of every age and rank, and especially to naval officers, an acquaintance with the laws which regulate these extraordinary aerial currents must be of great importance.  For a commander may be ordered, at a moment’s warning, either to carry his own ship, or to lead a squadron, or to guard a convoy, from the northern to the southern hemisphere, or perhaps from the West to the East Indies.  If, however, he have not previously made a tropical voyage or two, or have not studied the subject in its genuine theoretical spirit, as well as in the log-books of his predecessors, he may expect to find himself most wofully embarrassed, both on entering and on leaving the Trades.

Independently of all such public objects concerned in these inquiries, there appears to exist a very general interest in the Trade-winds, sufficiently strong to engage the attention even of unprofessional persons.  These vast currents of air, which sweep round and round the globe, in huge strips of more than twelve hundred miles in width, are in a manner forced on every one’s notice, from contributing to that boundless interchange of the productions of distant regions by which modern times are so agreeably distinguished from the old.

The great Monsoons, again, of the Indian and China oceans play almost as important a part in this grand nautical drama along the coasts of those remote countries.  These great phenomena will be found to obey precisely the same laws as their less fluctuating brethren the mighty Trades; and hence springs one of the chief delights of science when its study is conducted in a proper spirit.  If the pursuit of truth be engaged in with sincerity, phenomena apparently the most opposite in character, for example, winds in different parts of the earth, but in the same latitude, blowing in totally different directions at the same season of the year, will always prove in the end illustrative of one another, and of their common theory.