In several of the single-seated, high-speed monoplanes, as seen at the Paris show, it is possible to attain a flying rate of approximately eighty miles an hour. In such a machine, it is intended that the officer-pilot should, in war-time, effect a swift dash over the enemy’s lines, and fly back, without an instant’s delay, with whatever observations he has been able to make. Apart from being able to return very rapidly to Headquarters, the airman’s high speed would, of course, be an appreciable factor in his favour, when subjected to artillery fire. Such quick reconnoitring, carried out by the pilot of a fast-flying monoplane, will only be efficacious in detecting the movements of considerable bodies of troops. For detailed reconnaissance, without doubt, the two-seated monoplane, carrying its highly-skilled observer, will be relied upon—as, also, will the weight-carrying biplane, to which reference will be made in our next section. It may now, perhaps, be permissible to summarise some of the advantages of the latest-type military monoplanes. Primarily, of course, their value lies in their speed. In war-time, some reconnoitring flights will be more urgent than others; but it may be taken for granted that, in practically all circumstances, the speedy completion of a reconnaissance will be greatly to be desired. Thus, in the eyes of a Commander-in-Chief, the fast-flying monoplane will find the highest possible favour. A definite advantage of the monoplane’s speed will lie in its ability to fly in high, gusty winds. It will, indeed, require very adverse conditions to prevent the flight of a bold and expert airman, piloting an eighty-mile-an-hour machine. This point, naturally, will have especial significance during the progress of an actual campaign. In the forthcoming trials of military aeroplanes, to be conducted by the War Office, it is certain that powerful, two-seated monoplanes, propelled by seventy and hundred horse-power engines, will play an important part. II. Latest developments in biplane construction—The engine-in-front, weight-carrying machine. The varied experience of the year 1911, so far as the use of military biplanes was concerned, revealed very definite results at the Paris aeroplane exhibition in December. The influence of monoplane construction, upon the design of many of the biplanes shown, was marked. Clearly revealed, for example, was the comparatively new school—initiated by the Breguet—in which the engine is fixed in the bow of the biplane, as in monoplane practice, and a form of body almost identical with that of a monoplane is adopted. Such machines, seeing that they employ rear elevating planes, as do monoplanes, are biplanes only in the sense that they are fitted with two main-planes, set one above another. As a matter of fact, in regard to the Breguet—a notable representative of this type—the description "biplane" is occasionally dropped, and the machine called a "double-monoplane."