Extract of coffee is well known.  I believe it can be made of very good quality, but what is usually sold seems to me to be very much the contrary and not to be wholesome.

Tea and Coffee, without hot water.—­In Unyoro, Sir S. Baker says, they have no idea of using coffee as a drink, but simply chew it raw as a stimulant.  In Chinese Tartary, travellers who have no means of making a cup of tea, will chew the leaves as a substitute.  Mr. Atkinson told me how very grateful he had found this makeshift.

WATER FOR DRINKING.

General Remarks.—­In most of those countries where travelling is arduous, it is the daily care of an explorer to obtain water, for his own use and for that of his caravan.  Should he be travelling in regions that are for the most part arid and rarely visited by showers, he must look for his supplies in ponds made by the drainage of a large extent of country, or in those left here and there along the beds of partly dried-up water-courses, or in fountains.  If he be unsuccessful in his search, or when the dry season of the year has advanced, and all water has disappeared from the surface of the land, there remains no alternative for him but to dig wells where there are marks to show that pools formerly lay, or where there are other signs that well-water may be obtained.

Short Stages.—­I may here remark that it is a good general rule for an explorer of an arid country, when he happens to come to water, after not less than three hours’ travelling, to stop and encamp by it; it is better for him to avail himself of his good fortune and be content with his day’s work, than to risk the uncertainty of another supply.

Purity of Watering-places.—­Make no litter by the side of watering-places; and encourage among your party the Mahomedan feeling of respect for preserving the purity of drinking-water.  Old travellers commonly encamp at a distance from the watering-place, and fetch the water to their camp.

Signs of the Neighbourhood of Water.—­The quick intelligence with which experienced travellers discover watering-places, is so great that it might almost be mistaken for an instinct.

Intelligence of Dogs and Cattle.—­Dogs are particularly clever in finding water, and the fact of a dog looking refreshed, and it may be wet, has often and often drawn attention to a pond that would otherwise have been overlooked and passed by.  Cattle are very uncertain in their intelligence.  Sometimes oxen go for miles and miles across a country unknown to them, straight to a pond of water; at other times they are most obtuse:  Dr. Leichhardt, the Australian traveller, was quite astonished at their stupidity in this respect.

Trees and ordinary vegetation are not of much help in directing a traveller to water, for they thrive on dew or on occasional rain; but it is otherwise when the vegetation is unusually green or luxuriant, or when the vegetation is unusually green or luxuriant, or when those trees are remarked, that are seldom seen to grow except near water in the particular country visited, as the blackthorn-tree in South Africa.