The machines comprise a less straight-forward problem. The new service squadron is probably formed to fly a recently adopted type of aeroplane, of which the early production in quantities is hounded by difficulty. The engine and its parts, the various sections of the machine itself, the guns, the synchronising gear, all these are made in separate factories, after standardisation, and must then be co-ordinated before the craft is ready for its test. If the output of any one part fall below what was expected, the whole is kept waiting; and invariably the quantity or quality of output is at first below expectation in some particular. Adding to the delays of supply others due to the more urgent claims of squadrons at the front for machines to replace those lost or damaged, it can easily be seen that a new squadron will have a succession of Dates. Even when the machines are ready, and the transport leaves with stores, ground-officers, and mechanics, the period of postponement is not ended. All being well, the pilots will fly their craft to France on the day after their kit departs with the transport. But the day after produces impossible weather, as do the five or six days that follow. One takes advantage of each of these set-backs to pay a further farewell visit to one's dearest or nearest, according to where the squadron is stationed, until at the last the dearest or nearest says: "Good-bye. I do hope you'll have a safe trip to France to-morrow morning. You'll come and see me again to-morrow evening, won't you?" At last a fine morning breaks the spell of dud weather, and the pilots fly away; but lucky indeed is the squadron that reaches France without delivering over part of its possessions to that aerial highwayman the forced landing. It was at an aerodrome forty minutes distant from London that we patiently waited for flying orders. Less than the average delay was expected, for two flights of the squadron were already on the Somme, and we of the third flight were to join them immediately we received our full complement of war machines. These, in those days, were to be the latest word in fighting two-seaters of the period. Two practice buses had been allotted to us, and on them the pilots were set to perform landings, split-"air" turns, and stunts likely to be useful in a scrap. For the rest, we sorted ourselves out, which pilot was to fly with which observer, and improved the machines' accessories. An inspiration suggested to the flight-commander, who although an ex-Civil Servant was a man of resource, that mirrors of polished steel, as used on the handlebars of motor-cycles, to give warning of roadcraft at the rear, might be valuable in an aeroplane. Forthwith he screwed one to the sloping half-strut of his top center-section. The trial was a great success, and we bought six such mirrors, an investment which was to pay big dividends in many an air flight.