d to the tides. I think Dr. Whewell mentions that in particular situations the turn of the current occurs at a sufficient interval from the time of high or low water to perplex even the most experienced sailors.
_Bookbinding._--While the mischief of mildew on the inside of books has engaged some correspondents to seek for a remedy (Vol. ii., 103. 173.), a word may be put in on behalf of the _outside_, the binding. The present material used in binding is so soft, flabby, and unsound, that it will not endure a week's service. I have seen a bound volume lately, with a name of repute attached to it; and certainly the workmanship is creditable enough, but the leather is just as miserable as any from the commonest workshop. The volume cannot have been bound many months, and yet even now, though in good hands, it is beginning to rub _smooth_, and to look, what best expresses it emphatically, _shabby_, contrasting most grievously with the leather of another volume, just