ley is then decanted into another pot, where it is evaporated.  The plants in use, are those of which the wetted ashes have a saline and not an alkaline taste, nor a soapy feel.  As a general rule, trees that make good soap (p. 122), yield little saltpetre or other good equivalent for salt.  Salt caravans are the chief sustainers of the lines of commerce in North Africa.  In countries where salt is never used, as I myself have witnessed in South Africa, and among the Mandan North-American Indian tribes (Catlin, vol. i, p. 124), the soil and springs are “brack.”  Four Russian sailors who were wrecked on Spitzbergen, and whose well-known adventures are to be found in Pinkerton’s ‘Voyages and Travels,’ had nothing whatever for six years to subsist on—­save only the animals they killed, a little moss, and melted snow-water.  One of them died; the others enjoyed robust health.  People who eat nothing but meat, feel the craving for salt far less strongly than those who live wholly on vegetables.

Butcher.—­One man in every party should have learnt from a professed butcher, how to cut up a carcase to the best advantage.

Store-keeping.—­All stores should be packed and securely lashed, that it may be impossible to pilfer from them.  The packages of those that are in use, should be carried in one pair of saddle-gabs, to be devoted to that purpose.  These should stand at the storekeeper’s bivouac, and nobody else should be allowed to touch them, when there.  He should have every facility for weighing and measuring.  Lastly, it should be his duty to furnish a weekly account, specifying what stores remain in hand.

Wholesome Food, procurable in the Bush.—­Game and Fish.—­See sections upon “Hints on Shooting;” “Other means of capturing Game;” and upon “Fishing;” and note the paragraph on “Nocturnal Animals.”

Milk, to keep.—­Put it in a bottle, and place it in a pot of water, over a slow fire, till the water boils; let the bottle remain half an hour in the boiling water, and then cork it tightly.  Milk with one’s tea is a great luxury; it is worth taking some pains to keep it fresh.  A traveller is generally glutted with milk when near native encampments, and at other times has none at all.  Milk dried into cakes, intended to be grated into boiling water for use, was formerly procurable:  it was very good; but I cannot hear of it now in the shops.  Milk preserved in tins is excellent, but it is too bulky for the convenience of most travellers.  Dried bread-crumb, mixed with fresh cream, issaid to make a cake that will keep for some days.  I have not succeeded, to my satisfaction with this recipe.

Butter, to preserve.—­Boil it in a large vessel till the scum rises.  Skim this off as fast as it appears on the surface, until the butter remains quite clear, like oil.  It should then be carefully poured off, that the impurities which settle at the bottom of the vessel may be separated.  The clarified butter is to be put aside to be kept, the settlings must be used for common and immediate purposes.  Butter is churned, in many countries, by twirling a forked stick, held between the two hands, in a vessel full of cream; or even by shaking the cream in a bottle.  It is said that the temperature of the milk, while it is being churned, should be between 50 degrees and 60 degrees Fahr., and that this is all-important to success.