Tea made in tin mugs.--A correspondent a.s.sures me that he considers the Australian plan of making tea to be preferable to any other, for travellers and explorers; as it secures that the tea shall be made both well and quickly, and without the necessity of carrying kettles on horseback. Each person has a common tin quart pot and a pint pot, slung to his saddle; the tea and sugar are carried in small bags. The quart pot requires very little fire to make it boil. When it begins to boil, it is taken from the fire, the tea is dropped in, and the pint pot is placed on its top as a cover. When the tea is ready, the sugar is dropped into the pint, and the tea is poured from one pot to the other till it is mixed.
The pint is always kept clean for drinking out of, but not the quart, for the blacker it is, the sooner will the water boil.
Tea made over night.--To prepare tea for a very early breakfast, make it over night, and pour it away from the tea-leaves, into another vessel. It will keep perfectly well, for it is by long standing with the tea-leaves that it becomes bitter. In the morning simply warm it up. Tea is drunk at a temperature of 140 degrees Fahr., or 90 degrees above an average night temperature of 50 degrees. It is more than twice as easy to raise the temperature up to 140 than to 212 degrees, letting alone the trouble of tea-making.
Extract of Tea and Coffee.--Dr. Rae speaks very highly of the convenience of extract of tea. Any scientific chemist could make it, but he should be begged to use first-rate tea. The extract from first-rate tea makes a very drinkable infusion, but that from second-rate tea is not good, the drink made from the extract always a grade inferior to that made directly from the leaves. By pouring a small quant.i.ty of the extract into warm water, the tea is made; and, though inferior in taste to properly made tea, it has an equally good effect on the digestion.
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 subst.i.tute. 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 pa.s.sed 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.
Birds.--Some species of birds (as water-fowl, parrots, and the diamond bird) or animals (as baboons) afford surer promise; but the converging flight of birds, or the converging fresh tracks of animals, is the most satisfactory sign of all. It is about nightfall that desert birds usually drink, and hence it often happens that the exhausted traveller, abandoning all hope as the shades of evening close in, has his attention arrested by flights of birds, that give him new life and tell him where to go.
Tracks.--In tropical countries that have rainy and dry Seasons, it must be recollected that old paths of men or wild animals only mislead; they go to dry ponds that were full at the time they were trodden, but have since been abandoned on becoming exhausted.
Other Signs.--Well-water may be sought where the earth is still moist, though arid all around, or, failing that, where birds and wild animals have lately been scratching, or where gnats hover in swarms.
To find the Spring--From the number of birds, tracks, and other signs, travellers are often pretty sure that they are near water, but cannot find the spring itself. In this case the party should at once be spread out as skirmishers, and the dogs cheered on.
To probe for Well-water.--It is unusual, when no damp earth can be seen, but where the place appears likely to yield well-water, to force an iron ramrod deep into the soil; and, if it bring up any grains that are moist, to dig.
Pools of Water.--For many days after there has been rain, water is sure to be found among mountains, however desert may be their appearance; for not only does more wet fall upon them, but the drainage is more perfect; long after the ravines and stream-beds are quite dry, puddles and cupfuls of water will be found here and there, along their courses, in holes and c.h.i.n.ks and under great stones, which together form a sufficiency. A sponge tied to the end of a stick will do good service in lapping these up.
The sandy Beds of Watercourses in arid countries frequently contain pools of stagnant water; but the places where these pools are to be found are not necessarily those where they have been found in preceding years. The conditions necessary for the existence of a pool are not alone those of the rocky substratum of the river-bed, but more especially, the stratifications of mud and clay left after each flooding. For instance, an extensive bed of sand, enclosed between two layers of clay, would remain moist, and supply well-water during the dry season; but a trivial variation in the force and Amount of the current, in different years, might materially affect the place and the character of the deposition of these clay strata.
In searching the beds of partly dried-up watercourses, the fact must never be forgotten, that it is especially in little tributaries at the point where they fall into the main one, that most water is to be found; and the most insignificant of these should never be overlooked. I presume that the bar, which always acc.u.mulates in front of tributaries, and is formed of numerous layers of alluvial deposit, parallel to the bed of the great stream, is very likely to have one, at least, of its layers of an impervious character. If so, the bar would shut in the wet sand of the tributary, like a wall, and prevent it from draining itself dry.
When a river-bed has been long followed by a traveller, and a frequent supply of water found along it, in pools or even in wells, say at every 5 or 10 miles--then, should this river-bed appear to lose itself in a plain that is arid, there is no reason why the traveller should be disheartened; for, on travelling further, the water will be sure to be found again, those plains being always green and gra.s.sy where the water in such river-beds entirely disappears.
By Sea-sh.o.r.e.--Fresh water is frequently to be found under the very sands of the sea-sh.o.r.e, whither it has oozed underground from the upper country, and where it overlies the denser salt water; or else abuts against it, if the compactness of the sand resists free percolation. In very many places along the skirt of the great African desert, fresh water is to be found by digging two or three feet.
Fountains.--Fountains in arid lands are as G.o.dsends. They are far more numerous and abundant in limestone districts than in any others, owing to the frequent fissures of those rocks: therefore, whenever limestone crops out in the midst of sand deserts, a careful search should be made for water. In granite, and other primary rocks, many, but small springs, are usually seen.
The theory of ordinary fountains is simple enough, and affords help in discovering them. In a few words, it is as follows:--All the water that runs from them has originally Been supplied by rain, dew, or fog-damp, falling on the face of the land and sinking into it. But the subsoil and rocks below, are far from being of a uniform character: they are full of layers of every imaginable degree of sponginess. Strata of clay wholly impenetrable by water, often divide beds of gravel that imbibe it freely.
There are also cracks that make continuous channels and dislocations that cause them to end abruptly; and there are rents, filled with various materials, that may either give a free pa.s.sage or entirely bar the underground course of water. Hence, when water has sunk into the earth, it does not by any means soak through it in an equable degree. It is an easier matter for it to ooze many miles, along a layer of gravel, than to penetrate six inches into a layer of clay that may bound the gravel.
Therefore, whenever a porous earth or a fissured rock crops out to the light of day, there is, in ignorance of all other facts, some chance of a spring being discovered in the lowest part of the outcrop. A favourable condition for the existence of a large and permanent fountain, is where a porous stratum spreads over a broad area at a high level, and is prolonged, by a gradually narrowing course, to an outlet at a lower one.
The broad upper part of the stratum catches plenty of water during the wet season, which sinks into the depths as into a reservoir, and oozes out in a regular stream at its lower outlet. A fissured rock makes a still easier channel for the water.
[Fig 1 and Fig. 2].
As examples of ordinary cases of fountains, we will take those represented in the following figures. Fig. I is a mountain. Fig. 2 is a model, made to explain more clearly the conditions represented in fig. I.
It will be observed that there is a ravine, R, in front; a line of fault, L, M. N, on its left side, Supposed to be filled with water-tight rock; and a valley, V (fig. 1), on the extreme right. The upper part of the mountain is supposed to be much more porous than its base, and the plane which divides the porous from the non-porous rock, to cut the surface of the mountain along the line, A, N, M, B, C, D, E, F. The highest point of the plane is F, and the lowest point A. The effect of rain upon the model fig. 2 would be, to wet its upper half: water would ooze out along the whole of the lines A, N, and M, B, C, D, E, F; and there would be a small fountain at A, and a large one at M. But in the actual mountain, fig. 1, we should not expect to find the same regularity as in the model. The rind of the earth, with its vegetation and weather-impacted surface, forms a comparatively impermeable envelope to the mountain, not likely to be broken through, except at a few places. But ravines, such as r, would be probably denuded of their rind, and there we should find a line of minute fountains at the base of the porous rock. If there be no actual fountains, there would at least be some vegetation that indicated dripping water: thus the appearance is well known and often described, of a ravine utterly bare of verdure above, but clothed with vegetation below a sharply defined line, whence the moisture proceeds that irrigates all beneath. We should also be almost certain of finding a spring breaking forth near m or even near a. But in the valley V we should only see a few signs of former moisture, along e, f; such as bunches of vegetation upon the arid cliff, or an efflorescence of salts. Whenever a traveller remarks these signs, he should observe the inclination of the strata, by which he would learn the position of m, where the probability of finding water is the greatest. In a very arid country, the anatomy of the land is so manifest, from the absence of mould, that geological indications are peculiarly easy to follow.
Wells.--Digging Wells.--In default of spades, water is to be dug for with a sharp-pointed stick. Take it in both hands, and, holding it upright like a dagger, stab and dig it in the ground, as in fig. 1; then clear out the loose earth with the hand, as in fig. 2. Continue thus working with the stick and hand alternately, and a hole as deep as the arm is easily made. In digging a large hole or well, the earth Must be loosened in precisely the same manner, handed up to the surface and carried off by means of a bucket or bag, in default of a shovel and wheelbarrow.
[Fig. 1. And Fig. 2.--sketches of digging as described above].
After digging deeply, the sand will often be found just moist, no water actually lying in the well; but do not, therefore, be disheartened; wait a while, and the water will collect. After it has once begun to ooze through the sides of the well, it will continue to do so much more freely. Therefore, on arriving at night, with thirsty cattle, at a well of doubtful character, deepen it at once, by torch-light, that the water may have time to collect; then the cattle may be watered in the early morning, and sent to feed before the sun is hot.
It often happens when digging wells in sandy watercourses, that a little water is found, and that below it is a stratum of clay. Now if the digging be continued deeper, in hopes of more water, the result is often most unfortunate; for the clay stratum may prove extremely thin, in which case the digging will pierce it: then the water that had been seen will drain rapidly and wholly away, to the utter discomfiture of the traveller.
Kerkari.--I am indebted to correspondents for an account of a method employed in the plains of the Sikhim Himalaya, and in a.s.sam, where it is called a "Kerkari," also in lower Bengal, for digging deep holes. The natives take a freshly cut bamboo, say three inches in diameter: they cut it just above one of the knots, and then split the wood as far as to the next joint, in about a dozen places, and point the pieces somewhat. The other end of the instrument should be cut slantingly, to thrust into the earth, and its other end is afterwards worked vertically with both hands.
[Unlabelled figure of kerkari].
The soft soil is thus forced into the hollow of the bamboo, and spreads out its blades, as is intended to be shown in the figure. The bamboo is next withdrawn and the plug of earth is shaken out: it is then reintroduced and worked up and down as before. It is usual to drive a stake in the ground to act as a toothed comb, to comb out the plug of earth. Mr. Peal writes from a.s.sam:--"I have just had 4 holes dug in the course of ordinary work, in hard earth. Two men dug the holes in 1 1/2 hour; they were 3 feet 6 inches deep and 6 inches in diameter. I weighed the clay raised at each stroke. In 4 consecutive strokes the weights were 1 1/4 lbs., 1 3/4 lbs., 1 3/4 lbs., 2 lbs. Another trial gave 7 lbs.
lifted, after 5 or 6 strokes." According to the above data, an a.s.samese workman makes a hole, 1 foot deep and 6 inches in diameter in 6 minutes.
Holes 10 feet deep and 6 inches wide can be made, as I am informed, by this contrivance.
Protecting Wells.--The following extract from Bishop Heber, though hardly within the scope of the "Art of Travel," is very suggestive. "The wells of this country (Bhurtpoor, India), some of which are very deep, are made in a singular manner. They build a tower of masonry of the diameter required, and 20 or 30 feet high from the surface of the ground.
This they allow to stand a year or more, till its masonry is rendered firm and compact by time; then they gradually undermine it, and promote its sinking into the sandy soil, which it does without difficulty, and altogether. When level with the surface, they raise its walls higher; and so go on, throwing out the sand and raising the wall, till they have reached the water. If they adopted our method, the soil is so light that it would fall on them before they could possibly raise the wall from the bottom; nor, without the wall, could they sink to any considerable depth." A stout square frame of wood scantling, boarded like a sentry-box, and of about the same size and shape, but without top or bottom, is used in making wells in America. The sides of a well in sandy soil are so liable to fall in, that travellers often sink a cask or some equivalent into the water, when they are encamped for any length of time in its vicinity.
Scanty wells in hot climates should be brushed over, when not in actual use, to check their evaporation.
Snow-water.--It is impossible for men to sustain life by eating snow or ice, instead of drinking water. They only aggravate the raging torments of thirst, instead of a.s.suaging them, and hasten death. Among dogs, the Esquimaux is the only breed that can subsist on snow, as an equivalent for water. The Arctic animals, generally, have the same power. But, as regards mankind, some means of melting snow into water, for the purposes of drinking, is an essential condition of life in the Arctic regions.
Without the ingenious Esquimaux lamp (p. 205), which consists of a circle of moss wicks, fed by train-oil, and chiefly used for melting snow, the Esquimaux could not exist throughout the year, in the countries which they now inhabit.
That eating large quant.i.ties of snow should seriously disturb the animal system is credible enough, when we consider the very large amount of heat that must be abstracted from the stomach, in order to melt it. A mouthful of snow at 32 degrees Fahr., that is to say, no colder than is necessary for it to be snow at all, robs as much heat from the stomach, as if the mouthful had been of water 143 degrees colder than ice-cold water, if such a fluid may, for the moment, be imagined to exist. For the "latent heat" of water is 143 degrees Fahr. In other words, it takes the same quant.i.ty of heat to convert a ma.s.s of snow of 32 degrees into water of 32, as it does to raise the same ma.s.s of water from 32 degrees to 141 + 32 degrees = 175 degrees Fahr. It takes in practice about as long to melt snow of a low temperature into water, as it does to cause that same water to boil. Thus to raise snow of 5 degrees below zero Fahr. To 32 degrees, takes 37 degrees of heat, and it requires 143 degrees more, or 180 degrees altogether, to melt it into water. Also it requires 180 degrees to convert water of 32 degrees into water of 212 degrees, in other words, into boiling water.
Distilled Water.--It will take six or seven times as long to convert a kettle full of boiling-water into steam, as it did to make that kettle boil. For the "latent heat" of steam is 967 degrees Fahr.; therefore, if the water that was put into the kettle was 60 degrees, it would require to be raised through (212 degrees--60 degrees =) 152 degrees of temperature in order to make it begin to boil; and it would require a further quant.i.ty of heat, to the extent of 967 degrees (= about 6 1/2 times 152 degrees), to boil it all away. Hence, it is of no use to attempt to distil, until you have provided abundance of good firewood of a fit size to burn quickly, and have built an efficient fireplace on which to set the kettle. Unfortunately, fuel is commonly deficient in those places where there is a lack of fresh water.
Rate of Distillation.--A drop per second is fully equivalent To an imperial pint of water in three hours, or be an imperial gallon in an entire day and night.
The simplest way to distil, but a very imperfect one, is to light a fire among stones, near a hollow in a rock, that is filled, or can be filled with salt-water. When the stones are red-hot, drop them one by one into it: the water will hiss and give out clouds of vapour, some of which may be collected in a cloth, and wrung or sucked out of it. In the same way a pot on the fire may have a cloth stretched over it to catch the steam.
[Sketch of still as described below].
Still made with a Kettle and Gun-barrel.--There is an account of the crew of the "Levant" packet, which was wrecked near the cosmoledo Islands, who supplied themselves with fresh water by means of distillation alone, and whose Still was contrived with an iron pot and a gun-barrel, found on the spot where they were wrecked. They procured, On the average, sixty bottles, or ten gallons, of distilled water in each twenty-four hours. "The iron pot was converted into a boiler to contain salt water; a lid was fitted to it out of the root of a tree, leaving a hole of sufficient size to receive the muzzle of the gun-barrel, which was to set as a steampipe; the barrel was run through the stump of a tree, hollowed out in the middle, and kept full of cold water for the purpose of condensation; and the water so distilled escaped at the nipple of the gun-barrel, and was conducted into a bottle placed to receive it."
The accompanying sketch is taken from a model which I made, with a soldier"s mess-tin for a boiler, and a tin tube in the place of a gun barrel. The k.n.o.b represents the breech; and the projection, through which the water is dropping, the nipple. I may remark that there is nothing in the arrangement which would hurt the most highly-finished gun barrel; and that the trough which holds the condensing water may be made with canvas, or even dispensed with altogether.
Condensing Pipe.--In default of other tubes, a reed may be used: one of the long bones of an animal, or of a wading bird, will be an indifferent subst.i.tute for a condensing pipe.