My Dear Sir —As something towards enabling amateur and other geologists to communicate some of the results of their researches to their fellow-inquirers, I beg to offer the enclosed directions for making a preparation of gutta-percha and bees-wax, much better adapted for taking casts and moulds of fossils than gutta-percha itself; and also some useful remarks for the preparation of plaster-casts. These directions have been chiefly drawn up, at my request, by my friend, Mr. John Wetherell, of Highgate. I have also to observe that the prepared gutta-percha is capable of being applied to the purposes of the museum in another way, which has been suggested to me by a friend lately. Thus, have some narrow slips of tin folded into squares, of convenient sizes, and into these press some of the composition, and use these as pedestals for such fossil shells, and other specimens, as will not stand steadily by themselves. By warming these pedestals in hot water, they are readily softened so as to receive the fossils when pressed into them, and the latter can be at any time raised for examination.

Of course this composition, or even gutta-percha itself, is unfit for use in hot climates, and for transmission, by post or otherwise, to the tropics.