Page:On the various forces of nature and their relations to each other.djvu/195

Rh is not yet decidedly accomplished, and what the considerations of expense and other matters may be, I cannot tell. I am only here to tell you as a philosopher, how far the results have been carried; but I do hope that the authorities will find it a proper thing to carry out in full. If it cannot be introduced at all the light-houses—if it can only be used at one—why, really, it will be an honour to the nation which can originate such an improvement as this—one which must of necessity be followed by other nations.

You may ask, what is the use of this bright light? It would not be useful to us, were it not for the constant changes which are taking place in the atmosphere, which is never pure. Even when we can see the stars clearly on a bright night, it is not a pure atmosphere. The light of a light-house, more than any other, is liable to be dimmed by vapours and fogs; and where we most want this great power, is not in the finest condition of the atmosphere, but when the mariner is in danger—when the sleet and rain are falling, and the fogs arise, and the winds are blowing, and he is nearing coasts