(which might or might not be limited to a guarantee of interest on the necessary capital) it could no longer be said that the sea-level canal was impracticable. On the contrary, it would be the very route which would be likely to be selected. This solution of the problem would place no restriction on the number of ships passing through, or on the size of the oceangoing ships which would traverse the canal.

The more the situation is studied, the plainer it becomes that this solution of the problem,-the construction of a sea-level canal at Panama by the joint action and under the joint guarantee of the Great Powers-is that dictated by a combination of considerations of the greatest moment and deserving the most serious attention of statesmen concerned with the highest interests both of commerce and of peace. It is the route recommended by geographical considerations, and its construction would be a permanent improvement of the trade-routes of the world. The cost would be in great part saved of the already considerable expenditure of the wealth of the French people. The United States, whether by the medium of its Government or of its private citizens, would be spared a venture into a hazardous undertaking. The question of tolls would at once become a minor one. It might even become a question whether any tolls should be levied, or whether the cost of construction should not, as a payment once and for all, be divided among the commercial nations in proportion to their commerce. In any case, it would be feasible for a combination of

the Great Powers to provide for the ultimate extinction of tolls through a sinking fund.

Again, from the purely political side sources of possible conflict would be removed. Such a solution would be in complete harmony with the principles of the Clayton-Bulwer Treaty, so that that burning controversy would be permanently extinguished. It would also harmonise with the principles adopted by the Great Powers with reference to the Suez Canal, the interest in which is admitted not to be confined to one Power, and the regulation of which is provided for by a general international compact. For the constitution of the governing body of the canal an appropriate model can be found in the International Commission of the Danube, which now superintends the navigation of the waterway of Eastern Europe. An International Commission of Superintendence over a sealevel Panama Canal would not merely avert the creation of a standing menace of war, and of conflict between the commercial Powers of the world, but would serve, as does the Danube Commission, as a symbol of the solidarity of the civilised world and of that restored unity of the European race of which the Roman Empire was the first foreshadowing. A canal created under such auspices would be not alone a monument of engineering enterprise and a permanent subvention to the trade of the civilised world, but would stand for ever as one of those triumphs of peace which has its victories no less than

war.

LAST October I had the good fortune to be one of those allowed to attend our School of Ballooning at Aldershot; and, as my experiences while there had all the charm of novelty besides being of some little interest, I venture to give this account of what I saw of our War Balloons and their uses. I do so with the greater confidence since many of the points in connection with balloons and ballooning which, as a novice in the art, struck me most on first being made acquainted with them, have since been the subject of constant inquiries from friends who have asked me for my experiences in the air. I need hardly say that I am talking of friends who, like the great mass of the general public, are totally unacquainted with aerostatics, and who, like myself, were all the more impressed at hearing for the first time certain well-known physical facts in connection with ballooning which they had hitherto not realised or taken into consideration.

For example, how many people know that in the most furious gale that ever blew, the occupants of a "free" balloon are in an absolute calm; so calm indeed, that a newspaper might be opened and read with the same comfort as in a room, and, saving the danger of the gas, a lighted taper might be held in the hand with no possibility of its being blown out? When one sees a captive balloon beating about and struggling to be free in a strong breeze, it is hard to realise this fact; yet a fact it is, for the balloon, and its occupants then become of the wind itself, and travel with it as if they were part of it. Imagine yourself looking out of a window during a No. 431.-VOL. LXXII.

the car,

storm and seeing a balloon drift past at, say, seventy miles an hour; on land it is hard to stand up against the gale, and everything which the wind catches hold of is whirled away, but in the balloon the occupants would be as quiet as in a room; I will not add as unconcerned, for the prospects of effecting a landing in such a wind would be decidedly unpleasant.

Captive ballooning is so utterly unlike "free" work that it will be best to deal with it separately.

First and foremost, an ascent in a captive balloon except in calm weather is by no means a pleasant experience. The balloon is of course doing its utmost to free itself from the restraint of the wire rope; as the wind lulls, it may rise rapidly, while next moment a gust will cause it to dive after the manner of a kite, perhaps one hundred feet in a second; meanwhile the whole machine is jerking and quivering with the resultant forces of the ascensional power of the gas, the unequal pressure of the wind from moment to moment, and the strong, vibratory, retarding force of the wire rope. As the wind increases the balloon cannot rise against it, but is beaten down towards the ground; hence it is that with a strong, or even with a moderate wind, captive balloon work becomes simply an impossibility, for apart from the discomfort of a most intensified type of sea-sickness, which absolutely prostrates nine men out of ten, the violent motion of the balloon renders all observations impossible, while should it be beaten too near the ground there is the greatest danger of a regular smash. It is said that in the Suakin Expe

dition of 1885, owing to the violence of the wind and the small ascensional powers of the gas sent out, the captive balloon would not rise properly, but was driven down close to the tops of the mimosa trees in the scrub which was swarming with fanatical disciples of the Mahdi. It is difficult to imagine a more trying situation than that of the unfortunate reconnoitring-officer thus placed between the Scylla of appalling seasickness and the Charybdis of the Arab sword and spear.

It is this inability of a captive balloon to be of any use in windy weather which has caused some sceptics to declare ballooning to be a useless whim. It is certainly one of the greatest objections to the use of balloons in warfare; but in ordinary weather the value of captive balloons is unquestionable. As one ascends and sees the panorama of the earth unfolding itself below, and the network of roads assuming map-like proportions, it is not hard to realise the important part which captive balloons are likely to play in the warfare of the future.

But captive balloons become essentially the more valuable in proportion to the numbers of men forming the army to which they belong. It is of course possible that a captive balloon might afford very useful information to the commander of a small force of five or ten thousand men; but the value of such information would be altogether out of proportion to that which a balloon might give to a commander of one hundred thousand men. To give a rough example, had the French army been provided with captive balloons and able to work them on the heights of Amanvilliers on the 18th of August 1870, it is almost certain that the wide outflanking march of the Twelfth Saxon Corps would have been detected at an

early hour, with the obvious result that Bazaine would have had time to move his powerful reserve of the French Guard Corps, some twenty thousand strong, from the left of his position, where they were not wanted, to the right, a distance of seven miles, and thus materially alter the situation at that critical part of the great battlefield. Many such examples will present themselves to any student of military history; but the occasions upon which balloons would probably have been of inestimable value, are those where large armies were actually concentrated on the field of battle such as at Waterloo or Königgrätz.

An important feature in captive work is the method of communication between the balloon and the earth. This is absolutely provided for in theory by means of an insulated telephone wire in the core of the steel rope. In practice, however, owing to the vibration, the noise of the cordage, &c., it is found to be more certain and convenient to send written messages in small canvas bags, which clip on to the rope and run down by the force of gravity. A message can be sent up, in ordinary weather, by simply shouting, while if it be required to send up any light articles, they can be placed in a bag attached to a small balloon, which, being clipped on to the wire rope, runs up to the captive at once. There is a frivolous story to the effect that at a certain inspection, the thing which most interested the Great Personage who was inspecting the troops, was seeing a bottle of claret and some luncheon sent up to the occupants of a captive balloon by this means.

The principal danger in captive work is the always present possibility of the wire rope parting, not because of the obvious result that the balloon, being set free, would at once make off at speed, but for reasons of a very

simple technical nature, albeit, none the more pleasant by reason of their simplicity. It must be understood that when a captive balloon has been sent up the required height, the neck of the balloon has to be tied up so as to prevent the wind from exerting a pressure on the envelope and forcing out the gas, which would result in the balloon very shortly losing its lifting power and descending. In free runs the neck must always be wide open, for otherwise any sudden expansion of gas might burst the balloon. Hence, if a captive breaks away, it is bound to make an unduly rapid ascent since it is suddenly released from the restraint as well as the weight of the wire rope. Of course in such an emergency the gas would at once commence to expand furiously, and, unless the neck of the balloon were instantly opened and kept open, the envelope would inevitably burst. In the shocking accident at the Crystal Palace in 1892, when poor Dale and his comrades lost their lives, the balloon was started with too much lift and commenced to rise with undue rapidity. Dale, the aeronaut, realising the danger opened the neck and, in his anxiety to see that it was clear, looked into it; and it is supposed that his head checked the outrush of heated gas, with the result that the envelope instantly burst with terrible results.

The obvious remedy, if a balloon be thus rising, is to open the valve; but here again there is a chance of doing more harm than good, since if the valve be opened too freely, not only will the ascent be checked, but a rapid descent substituted. Here, again, the obvious thing is to throw out ballast; but if this be also done in a panic, too much is sure to be thrown, the balloon will again rise with dangerous rapidity, and the last state of that aeronaut be decidedly worse

than

the first. From all this it will be seen that occasions may very easily arise in balloons as on shipboard, where a cool head and thorough command of nerve are the only way out of a dangerous accident.

Photography from a captive balloon is not as a rule of much value for

military purposes. The ground immediately below can indeed be instantaneously reproduced in map-like form; but the perspective is SO forced, and the distances SO exaggerated, according to my small experiences, that the results are of little worth.

During last autumn we had many days of foggy weather, during which time we never saw the sun and when balloon-work was necessarily interrupted. On the 8th of October there were both dense fog and frost, and for the sake of practice a captive balloon was sent up. When about four hundred feet above the ground we lost sight of the earth altogether, and rose with the peculiar vibratory motion due to the action of the line and windlass of a captive balloon in still weather. The fog was very thick, and all we could see outside of the balloon was the wire rope descending almost vertically until lost to view about one hundred feet below the car. At seven hundred and fifty feet it became less foggy; another fifty feet brought us into a stratum of vapour through which the sun's rays were feebly struggling, and at eight hundred and fifty we suddenly seemed to burst forth from the nebulous atmosphere into the most brilliant sunlight. As we did so, a huge spectral balloon was to be seen shadowed on the clouds below. Up we went, the aneroid running back as quickly as the second hand of a watch, until it registered one thousand five hundred and twenty-five feet above the ground. Here we felt the brake

was being applied far in the depths below, and we remained anchored in mid-air for some time. The scene was a very beautiful one; hundreds of feet below us lay a sea of billowy, soft white clouds,extending in all directions for many miles, while above, the clear and dazzling blue sky seemed to belong to a Mediterranean climate. It was hard to realise that below the brilliant atmosphere we were in lay Aldershot and the surrounding country enshrouded in impenetrable gloom. Save for the wire-rope, which hung below us for over seven hundred feet before it was lost to view in the clouds beneath, we seemed to have no connection with mother-earth, but to be poised in a universe of our own.

We now come to the far more pleasant part of ballooning, namely, free-run work. Here the greatest importance is attached to having an adequate amount of ballast on board, since it is an axiom in ballooning that the life of a balloon depends on the amount of ballast it will carry. Perhaps there is no single thing in ballooning which requires greater experience than a knowledge of how to expend ballast judiciously. It is a common saying, that a skilled aeronaut is worth a couple of bags of ballast; in other words that he will economise that amount in a given run, and so prolong the life of the balloon proportionately. When only one bag, say of fifteen to twenty pounds, is left, it is necessary to descend without delay, for the safety of a descent often depends upon having sufficient ballast to check the fall properly, or, should some unforeseen danger appear, such as telegraph wires, &c., to have the power of rising clear and descending again at a more suitable spot. Experience has proved that about twenty-five pounds of ballast should be allowed for every hour's run; hence a war-balloon, which is required to keep up for eight hours, should

have two hundred pounds of ballast. The process of ballasting up a balloon previous to the start is a delicate operation. The crew take their

places and all the gear is stowed, instruments lashed at convenient places for use, and the bags of fine sand placed in the car until the balloon is in perfect equilibrium. Suppose a lift of four pounds to be required; this is obtained by taking out that amount, and the aeronaut in command, when he feels the balloon lifting to his satisfaction, lets go the hand of the man on terra-firma and the balloon is off.

One of my principal objects in volunteering for the balloon-course was to ascertain to what extent it would be possible to make a useful reconnaissance sketch of the country passed over during an extended freerun. From former experiences of sketching under all sorts of circumstances and in all sorts of manners, conventional and the reverse, I was convinced that by a slight modification of the process known as timesketching, it would be quite possible to do very accurate topographical work from a free balloon with one of the late Colonel Richards's cavalry sketching-cases. Ten years ago I had used one of these excellent inventions when sketching similarly by time, one day by the rate of the camels marching across the Bayuda Desert at two to two and a half miles an hour, and another by the rate of Gordon's famous penny steamers, steamers, steaming

at three or four knots against the strong Nile current, or at ten to twelve with it. All travellers and explorers, as well as all military men, owe Colonel Richards a debt of gratitude for having, by means of his simple system of sketching, placed it within their power to delineate a country while actually moving through it.

The first free run I made was