And the British aviator has discovered and is rapidly developing an altogether fresh branch of air activity in the machine-gun attack at a very low altitude.  Originally I believe this was tried in western Egypt, but now it is being increasingly used upon the British front in France.  An aeroplane which comes down suddenly, travelling very rapidly, to a few hundred feet, is quite hard to hit, even if it is not squirting bullets from a machine gun as it advances.  Against infantry in the open this sort of thing is extremely demoralising.  It is a method of attack still in its infancy, but there are great possibilities for it in the future, when the bending and cracking German line gives, as ultimately it must give if this offensive does not relax.  If the Allies persist in their pressure upon the western front, if there is no relaxation in the supply of munitions from Britain and no lapse into tactical stupidity, a German retreat eastward is inevitable.

Now a cavalry pursuit alone may easily come upon disaster, cavalry can be so easily held up by wire and a few machine guns.  I think the Germans have reckoned on that and on automobiles, probably only the decay of their morale prevents their opening their lines now on the chance of the British attempting some such folly as a big cavalry advance, but I do not think the Germans have reckoned on the use of machine guns in aeroplanes, supported by and supporting cavalry or automobiles.  At the present time I should imagine there is no more perplexing consideration amidst the many perplexities of the German military intelligence than the new complexion put upon pursuit by these low level air developments.  It may mean that in all sorts of positions where they had counted confidently on getting away, they may not be able to get away—­from the face of a scientific advance properly commanding and using modern material in a dexterous and intelligent manner.

III.  THE WAR LANDSCAPE

1

I saw rather more of the British than of the French aviators because of the vileness of the weather when I visited the latter.  It is quite impossible for me to institute comparisons between these two services.  I should think that the British organisation I saw would be hard to beat, and that none but the French could hope to beat it.  On the Western front the aviation has been screwed up to a very much higher level than on the Italian line.  In Italy it has not become, as it has in France, the decisive factor.  The war on the Carso front in Italy—­I say nothing of the mountain warfare, which is a thing in itself—­is in fact still in the stage that I have called B. It is good warfare well waged, but not such an intensity of warfare.  It has not, as one says of pianos and voices, the same compass.