Savages, however, take such pains to efface any mark they may find left by white men, entertaining thoughts like those of Morgiana in the ‘Arabian Nights’ tale of the Forty Thieves, that it would be most imprudent to trust to a single mark.  A relief party should therefore be provided with a branding-iron and moveable letters, and with paints, and they should mark the tree in many places.  A couple of hours spent in doing this would leave more marks than the desultory efforts of roving savages would be likely to efface.  A good sign to show that Europeans have visited a spot is a saw mark (no savages use saws):  it catches the eye directly.

A system occasionally employed by Arctic expeditions, of making a cache 10 feet true north (and not magnetic north) from the cairn or mark, deserves to be generally employed, at least with modifications.  Let me therefore suggest, that persons who find a cairn built of a tree marked, so as to attract notice, and who are searching blindly in all directions for further clue, should invariably dig out and examine that particular spot.  The notice deposited there may consist of no more than a single sentence, to indicate some distant point as the place where the longer letter is buried.  I hope it will be understood, that the precaution of always burying a notice 10 feet true north of the cairn mark is proposed as additional to and not in the place of other contrivances for giving information.  There will often arise some doubt as to the exact point in the circumference of the cairn or mark whence the 10 feet measurement should be made.  This is due to the irregularity of the bases of all such marks.  Therefore, when searching for letters, a short trench, running to the north, will frequently have to be dug, and not a mere hole.  I should propose that the short notice be punched or pricked on a thin sheet of lead, made by pouring two or three melted bullets on a flat stone, and that the plate so made and inscribed should be rolled up and pushed into a hole bored or burnt through the head of a large tent peg.  The peg could be driven deeply in the ground, quite out of sight, without disturbing the surrounding earth.  It might even suffice to pick up a common stone and to scratch or paint upon it what you had to say, and to leave it on the ground, with its written face downwards, at the place in question.

To secure Buried Letters from Damp.—­They may be wrapped in waxed cloth or paper, if there be no fear of the ravages of insects.  Lead plate is far more safe:  it can be made easily enough by a traveller out of his bullets. (See “Lead.”) A glass bottle (with something that insects cannot eat, such as lead-plate, sealing-wax or clay, put carefully over the cork) or an earthen jar may be used.  The quill of a large feather will hold a long letter, if it is written in very small handwriting and on thin paper, and it will preserve it from the wet.  After the letter has been rolled up and inserted in the quill, the open end of the latter may be squeezed flat between two stones, heated sufficiently to soften the quill (see “Horn”) but not so hot as to burn it, and then, for greater security against wet, the end of the quill should be twisted tight.  Wax affords another easy means of closing the quill.