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manner that the Gross II. was used at the German manoeuvres last year. We must anticipate very interesting results from these airships before long, and we must bear in mind that the non-rigid type is handy, and may yet become a dangerous rival to the Zeppelin. Our little experimental Army airship the Beta, with her 35 H.P. and low speed, cuts a very sorry figure when compared with these foreign squadrons of the air.

The range of the aeroplane is in principle dependent on fuel supply, which in practice allows at present a flight of about 150 miles at the rate of 50 miles an hour without descending. The world's record for an aeroplane flight with two passengers is at present 2 hours and 51 minutes. As the pilot of an aeroplane is almost wholly occupied with navigating his craft, an aeroplane which cannot take a second passenger to make observations is of little use for military purposes. The aeroplane has risen to a height of 4146 feet. If its motor fails it must come down, though not necessarily to grief. Its high speed, simplicity, cheapness, portability, comparative invulnerability to fire, and power to ascend and descend with ease, are in its favour, but it cannot remain motionless in the air, its power in attack is as yet undeveloped, and it is adapted for the moment only to short flights.

To what extent are improvements likely to take place in the immediate future? Improvements in the tensile

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strength of aluminium alloys, and in the trustworthiness and power of motors, will certainly decrease weights and increase the speed of dirigibles, perhaps up to 40 miles an hour, and increase the range to 1500 miles or more for the rigid type. If reserve buoyancy can be supplied by compressed gas, the range will be greatly extended, while the same result will also be obtained by more scientific use of plane surfaces. is sure to remain great, and the extreme limits have probably not yet been reached. Size means gain in lifting power over areas, for the first cubes as the second squares. The temptation is therefore to build big, but other factors enter into the calculation as size increases and end by imposing limits to size. There is no immediate probability that any dirigible will be able to make headway against strong winds, but on calm days and in moderate winds the arrival of German dirigibles above some of our seaports and a part of our territory must be anticipated in time of war.

There is some loss of buoyanoy in navigating above the sea owing to the condensing of moist air on an airship, but specially designed envelopes will doubtless overcome this difficulty. It is said that a fabric has been made which, in the dampest atmosphere, does not increase weight more than a third of an ounce to the square yard.

The greatest difficulty not yet wholly overcome is that of navigating the air with certainty in any given direction,

especially over the sea, when there is no point de repère for observers aloft. It is probable that the gyro-compass, which has been successfully introduced into the German Navy, will prove suitable for airship work. A real difficulty to the airman is the danger that, even if an airship is apparently heading in the required direction at full speed, the movement of the air may all the time be causing a lateral or angular drift. An airship sextant, capable of rapid manipulation, is required to enable the airman to determine and maintain a course against lateral drift due to the wind. On the other hand, the power possessed by the airship of remaining at the same altitude where air currents are fairly constant is favourable to equable flight. With his German gyro-compass, with an accurate chronometer for determining longitude, with wind vanes on ball mountings to show leeway, and with anemometers connected with speed and revolution - counting indicators to record distance travelled, the airman is already pretty well equipped for locomotion in a required direction, even at sea, and such difficulties as still remain to be overcome do not appear great by the side of others which have already been surmounted. As for the fog so prevalent in the North Sea, M. de Lesseps showed us only the other day that even the aeroplane can rise above the banks and be steered by the sun.

The dirigible is the best existing type of airship for

purposes of strategical reconnaissance and attack. Observers on the deck of a dirigible can see ships at a distance of 30 miles in fair weather. On land, isolated men can be observed from a height of 2000 feet, horses and small groups of men from a height of 3000 feet, while from a height of 4000 feet the Patrie observed the smallest movements of formed bodies of troops at the Satory camp and obtained very clear telephotographs of them. It is difficult to exaggerate the value of the dirigible for purposes of strategical reconnaissance, and as wireless telegraphy has been adapted to use by airships there cannot be much doubt that in favouring weather the best watch in the air will secure the advantage of prompt and accurate information of the movements of fleets and flotillas at sea and of masses on land.

It is possible for observers on airships to detect ships at sea from positions far beyond the reach of guns, and to escape destruction by artillery on land, thanks to speed, height above the ground, and the difficulty of ranging. It will not be very convenient to mount guns on airships, but specially designed guns will probably become necessary for use against other airships, and may be fired by compressed air. The projectiles of airship guns may possibly give out a jet of flame and a smoke "tracer" on discharge, but the Germans possess a sensitive fuze which is said to act upon contact with even such light fabrics as envelopes of airships. Whether some form of unin

flammable gas, steam, or ammonia can be discovered or adapted to the use of dirigibles in order to overcome the dangers arising from inflammable hydrogen gas is a question that remains open. On the whole, helium, which is almost as light as hydrogen and not inflammable, appears to be the best substitute for hydrogen at present known, but very little isolated helium as yet exists.

Contrivances for dropping or firing explosives upon ships, troops, and works below will form the main offensive armament of the airship which will also strive to play the part of the hawk to the heron of the rival airship. An airship which can soar higher than her foe and travel faster has this foe at her mercy. Guns for repelling airship attack on sea or land will rely on flame - fire or sensitive fuzes. On rare occasions shrapnel may be effective if bullets of a special design are introduced into the shell.

An object moving through the air at a great height, not necessarily on a horizontal plane, at an unknown range, and at a speed of 25 to 40 miles an hour, is not easy to hit. The rigidity of the trajectory, admitted for the construction and use of sights for horizontal fire, is no longer true when firing into the air. Rifle-fire against an airship is practically unaimed fire unless special sights are introduced. The perforation of gas envelopes by small calibre bullets has, moreover, been proved by French and German experiments to have little effect in reducing buoy

ancy. The carriages of fieldguns, again, do not as a rule permit of fire at angles of elevation greater than 16° or 20° unless the trail is buried in the ground. At a height of 3000 to 4000 feet the airship will practically have nothing to fear from the fire of these weapons. Howitzers and some types of heavy artillery will theoretically be more effective, but we should be sanguine to suppose that the fire of any cumbrous cannon will be anything but most disappointing against such swiftly moving marks as modern airships. Effective fire against airships, whether from ships or from land, can only be expected from special guns using special projectiles. The Germans realised this fact at a very early date, and are well ahead of other Powers with their 7·5-c. and 10-5-c. anti-airship guns, which have an extreme vertical range of 6800 and 12,400 yards respectively. Messrs Vickers have designed a 3-pr. gun for high angle fire, but, thanks to the very thorough experiments at Dantzig and elsewhere, Germany is as far ahead of us in anti-airship artillery as she is in airships themselves.

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While airships may special artillery for attacking their kind, their main offensive menace will rest with the projectiles or explosives fired or dropped upon the mark below. It is true that we have signed and ratified an international declaration which prohibits "the discharge of projectiles and explosives from balloons, or by other new methods of a similar nature," but Germany is

not a party to this declaration, to have arrived is that 50 per cent of projectiles dropped from a height of 4500 feet can be made to fall within a square with sides of 25 yards. The 'Punch' artist was a little behind the times when he depicted the disappointment of the foreign airmen who had "missed London." When more scientific instruments are devised, the 20-foot broad funnels of warships will be the airman's bull's-eyes. Already nothing prevents the effective offensive use of airships in war, within their present limits of range, and in favourable weather, which after all occasionally occurs, even in Scotland. The mean hourly wind velocity, judging by the "Challenger" observations, is only 17 miles at sea, while on land it is only 12 miles, but increases in higher altitudes. Airships have to contend, over our islands, with a higher average velocity of wind than is found in France or Germany. But we must expect every year to hear of dirigibles with greater range, higher speed, and better carrying capacity, which in their turn will increase the military results which may be expected from these types in their three main dutiesnamely, communication, reconnaissance, and attack.

so we are forced to ignore it. The velocity acquired by bombs dropped from a great height is considerable, and up to a certain point increases with the height. It is true that explosives are much less harmful against certain targets, for instance a bomb-proof, when they are not enclosed in a strong and heavy shell, but in the future contest between the airship bomb and the armoured deck the bomb will probably win in the end. At present spherical bombs to the number of thirty, with thin walls, and each containing 44 lb. of explosive substance, can be carried by an airship of the Patrie type. Very much more can be carried by the larger Zeppelins. The transport and the projection at one discharge of a ton of explosive substance are not beyond the reach of attainment, and this amount will be much more than enough to wreck any warship now afloat. It is commonly supposed that the sudden loss of weight caused by the discharge of projectiles will compromise the stability of airships. French experiments appear to show that this danger has been exaggerated, and it seems to be probable that loss of ballast can be compensated by a proper arrangement of escape valves.

M. Juchmès, the pilot of the Lebaudy, proved long ago that an airship can remain poised and practically immobilised in the air even in a wind. Very fair practice has already been made in dropping bombs on selected marks, and the conclusion at which the French appear

Progress in the military use of aeroplanes will chiefly take the form of increased range and speed, and perhaps of increased size. The limit of range cannot be calculated with any precision, but may extend to 500 or even 1000 miles before very long, while enthusiasts expect a speed of 200

miles an hour, and consequently hope to combat the highest winds, which are not much over 100 miles an hour. The Gnome rotary engine has lately effected a marked improvement in aeroplane flight, and as better and lighter motors are placed on the market there is sure to be constant progress, while safety may be increased by duplicate engines and propelling gear. The fact that a skilful pilot of an aeroplane will be able to face winds which will keep dirigibles in their harbours will always give the aeroplane a place in the aerial forces of every nation, while for purposes of tactical reconnaissance, both on land and sea, the aeroplane promises to be invaluable. It will not easily be open to attack by the slower dirigible. It requires no expensive, complicated, and ponderous plant. It is much less exposed to the buffets of the wind when at rest. It may turn out to be the destroyer of the air, and in any case it is sure to have its use in war. It would be very imprudent for us to tie ourselves to any particular type of airship for naval and military purposes at this moment. We must excel in each type and remain constantly alert to what the foreigner is doing.

Scepticism respecting the utility of airships in war is not an attitude that can be justified any longer. We must all in the end yield to evidence and to proofs of tangible achievements. The questions then arise how airships are likely to be employed in a future war, how they can best

be met, and what measures it behoves us to take. In case of war between England and Germany, the object of the latter will obviously be-and quite rightly-to use an arm which we do not yet possess in such a manner that she may obtain early and accurate information of our naval dispositions and movements, and at the same time cause us the maximum amount of moral and material damage.

In the discussion of an interesting paper read by Lord Montagu of Beaulieu before the National Defence Association last year, allusion was made to the probability of airship attack upon the nerve centres of London, such as the General Post Office, the Telephone Exchanges, the Bank of England, the Royal Palaces, the Railway Termini, and so on. Nearly all the speakers thought that such attacks were admissible and probable. It is true, and the fact may prove most interesting in its consequences, that the gobe-mouche and the "mafficker" may hereafter come within sight of the enemy, and for the first time realise his existence and their danger. But my view is that great towns like London and Edinburgh are to some extent protected against aerial bombardments by the inherent uselessness and inexpediency of such measures even from the German point of view. Great Powers like England and Germany do not make war on women and peaceful citizens. I do not think that it would profit the cause of Germany in the least to

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