ports and dangers, adapted to all classes of seamen, will obviously be among the essential parts of the survey; but there will also be opportunities of collecting auxiliary information which, when digested, may be made extensively useful to those who may have to visit that coast;—such as places of refuge after any disaster at sea; ports where pilots are requisite; the most advantageous methods of obtaining water, wood, and other supplies; the general resources and productions on which vessels may depend; the usual effects of the climate in the rainy and in the dry seasons; and notice should be given of those spots which are peculiarly unhealthy. In short, no facts can be useless in compiling directions hereafter.
It has been suggested by some geologists that the coral insect, instead of raising its superstructure directly from the bottom of the sea, works only on the summits of submarine mountains, which have been projected upwards by volcanic action. They account, therefore, for the basin-like form so generally observed in coral islands, by supposing that they insist on the circular lip of extinct volcanic craters.
In order, by a satifactory experiment, to bring this question to a direct issue, their Lordships have ordered you to be supplied with a complete set of the boring- apparatus used by miners; leaving it to your own judgment to select any coral island which may be well adapted to the purpose, and which will lead you as little as possible from the line of your survey. They wish you to fix upon a convenient spot of the island where the operation cannot be disturbed by the surf, and there to bore perpendicularly, so as to perforate the whole thickness of the coral, and to enter the tool suffi-
