(From our own Correspondent.)

Berlin, Friday.

Germany’s fleet of “air cruisers,” or dirigible airships, will, it is proudly announced to-day, presently number six:—

• Count Zeppelin’s III., rigid type.
• Count Zeppelin’s IV., rigid type, which has done a twelve-hour flight and will be taken over by the Government, with No. III., for £100,000, after a twenty-four-hour test.
• Major Gross’s Army airship, half rigid.
• Motor Airship Study Society’s old airship, non-rigid.
• Major von Parseval’s non-rigid ship building for the above society.
• New airship, of which details are kept secret, nearly ready at the works of the Siemens-Schuckert Electric Company.

The first announcement of the last-named airship was given in The Daily Mail several months ago. The company has engaged a celebrated military aeronaut, Captain von Krogh, as commander of the vessel. The Study Society’s new non-rigid ship will be sold to the War Office as soon as she has completed her trial trips.

The Army will then possess three dirigibles, each representing one of the three opposed types of construction—rigid, half-rigid, and non-rigid—with a view to arriving at a conclusion on their merits.

..........

“Only a year or so ago, our authorities were talking of aerial navigation in its relation to war as ‘an interesting and instructive study.’ Now we must reckon it as the gravest problem of the moment. The cleverest aeronauts in England should be called upon at once to design an airship, not only as efficient as that of Count Zeppelin’s, but possessed of even greater speed. (His average was said to be about 34 miles an hour.) In speed will lie the supremacy of the air when it comes to actual warfare. Of two opposing airships, the faster will be able to outmanoeuvre its adversary and hold it at its mercy.”—Daily Mail, July 11, 1908.

COMMAND OF THE AIR.

GERMANY AS THE AERIAL POWER.

TEUTONIC VISION.

A LANDING OF 350,000 MEN.

Herr Rudolph Martin, author of books on war in the air and “Is a World-War Imminent?” points out how England is losing her insular character by the development of airships and aeroplanes.

“In a world-war,” he said to me, “Germany would have to spend two hundred millions sterling in motor airships, and a similar amount in aeroplanes, to transport 350,000 men in half an hour during the night from Calais to Dover. Even to-day the landing of a large German army in England is a mere matter of money. I am opposed to a war between Germany and England, but should it break out to-day, it would last at least two years, for we would conclude no peace until a German army had occupied London.

“In my judgment it would take two years for us to build motor airships enough simultaneously to throw 350,000 men into Dover via Calais. During the same night, of course, a second transport of 350,000 men could follow. The newest Zeppelin airship can comfortably carry fifty persons from Calais to Dover. The ships which the Zeppelin works in Friedrichshafen will build during the next few months are likely to be considerably larger than IV., and will carry one hundred persons. There is no technical reason against the construction of Zeppelin airships of 1,100,000 or even 1,700,000 cubic feet capacity, or twice or three times the capacity of IV. (500,000 cubic feet).

“I am at present organising a German ‘Air Navy League,’ to establish air-traffic routes in Germany. Aluminium airships could carry on regular traffic between Berlin and London, Paris, Cologne, Munich, Vienna, Moscow, Copenhagen, and Stockholm. In war time these ships would be at the disposal of the German Empire.

“The development of motor airship navigation will lead to a perpetual alliance between England and Germany. The British fleet will continue to rule the waves, while Germany’s airships and land armies will represent the mightiest Power on the Continent of Europe.”—Daily Mail, July 11, 1908.

It is needless to say that the above was written before the wreck of Zeppelin’s machine.

For many years scientific mechanicians and mathematicians have told us that the navigation of the air was quite possible. They have said it is only a question of motive power; “Give us a motor that is sufficiently light and strong, and we will very soon give you a practical flying machine.” A domestic goose weighs about 12 lbs., and it has been estimated that it only exerts about one-twelfth part of a horse-power in flying—that is, it is able to exert one man-power with a weight of only 12 lbs., which seems to be a very good showing for the goose. However, at the present moment, we are able to make motors which develop the power of ten men—that is, one horse-power—with less than the weight of a common barnyard fowl. Under these conditions it is quite evident that if a machine can be so designed that it will not be too wasteful in power, it must be a success. It is admitted by scientific men that all animals, such as horses, deer, dogs, and also birds, are able to develop much more dynamic energy for the carbon consumed than is possible with any thermodynamic machine that we are able to make. It may be said that many animals are able to develop the full dynamic energy of the carbon they consume, whereas the best of our motors do not develop more than 10 per cent. of the energy contained in the combustibles that they consume; but, as against this, it must be remembered that birds feed on grass, fruit, fish, etc., heavy and bulky materials containing only a small percentage of carbon, whereas with a motor we are able to use a pure hydrocarbon that has locked up in its atoms more than twenty times as much energy per pound as in the ordinary food consumed by birds. I think, in fact I assert, that the time has now arrived, having regard to the advanced state of the art in building motors, when it will be quite a simple and safe affair to erect works and turn out successful flying machines at less cost than motor cars; in fact, there is nothing that stands in the way of success to-day. The value of a successful flying machine, when considered from a purely military standpoint, cannot be over-estimated. The flying machine has come, and come to stay, and whether we like it or not, it is a problem that must be taken into serious consideration. If we are laggards we shall, unquestionably, be left behind, with a strong probability that before many years have passed over our heads, we shall have to change the colouring of our school maps.

As the newspaper accounts that we receive from the Continent give all weights and measures in the metric system, it is convenient to have some simple means at hand to convert their values into English weights and measures. I therefore give the following, which will greatly simplify matters both for French and English measurements:—