ii. _Maurice Farman Biplane._--A type of weight-carrying machine that has survived is that designed by Mr. Henry Farman’s brother, Mr. Maurice Farman. This machine has extensions to its main surfaces, which enable it to carry a considerable weight. It has been found capable of remaining in the air a very long time, which is an important consideration for war use, especially when the aëroplane is on the offensive. It is capable of flying at a very low speed. A disadvantage is that it requires very skilful piloting, especially when used in high winds. THE BREGUET BIPLANE. Very conspicuous in the Paris Salon exhibitions has been the Breguet biplane. This is one of very advanced type; it is a military machine _par excellence_. Simplicity and portability throughout are its distinguishing features, and these are the essence of a machine designed for war. One might almost call it a combination of monoplane and biplane construction. There is the familiar tapering of the framework, with controlling planes at the end, such as in the Blériot, but two superposed planes, instead of the bird-like projecting wings of the Blériot, are above and below the body of the machine. Steel enters largely into the design. There is a maximum of supporting struts between the main surfaces. These are constructed with thin metal ribs, and are therefore flexible, an exceedingly important feature, rendering the machine exceptionally stable in high and gusty winds. For portability the main surfaces can be taken out of position in a few minutes. By the excellent method of hinging the planes to the body of the machine the former may be turned back and folded up beside the body of the machine. The aëroplane can therefore be described as a folding-up one. It can therefore travel on the road like a motor-car, instead of having to be packed up and conveyed in a wagon. This method of road conveyance would be impracticable with a machine with its wings outspread. THE SHORT DOUBLE-ENGINED AËROPLANE. How many times have engines failed during flight on both monoplanes and biplanes! How many tragedies have thus been enacted! Time and experience indeed have mitigated this type of aërial disaster. The improvement in engines has been one cause of salvation in this respect, the practice of vol-planing the other. But even now from the seat of war comes the news of engines that fail and machines that drop into the realm of the enemy. The old proverb of having two strings to one’s bow should apply to aëronautics.