As the work speeded up the strain grew on pilots and machines, which also means on the mechanics. Some of the planes came home with bullet-holed fabrics, shot-through frames, and damaged engines. All the holes had to be patched, all the frames had to be mended, all the engines had to be repaired. The strain and pressure on a flimsy structure being hurtled through the air at speeds running from 100 to 200 miles per hour is bound to result in a certain amount of working loose of parts, stretching of stays, slackening of fabrics, give and take in nuts and bolts, yielding and easing of screws; and since the pilot's and the machine's life and the Squadron's efficiency alike depend on every one of the hundreds of parts in a machine's anatomy being taut and true, or free and easy-running, as the case may be, the mechanics began to find a full normal day's work merely in the overhauling and setting up of the machines, apart altogether from fight-damage repairs. Two days before the Push began the mechanics put in a hard working day of fifteen hours out of the twenty-four; the day before the Push they started at 6 a.m. and finished at 1 a.m. next morning--and with the first patrols due to start out at dawn. But they finished with every machine trued to a hair-line, braced and strung to a perfection of rigidity, with engines running as sweet as oil, and giving their limit of revolutions without a hint of trouble, with every single item about them overhauled, examined, adjusted and tested as exhaustively and completely as if a life hung on the holding of every bolt, brace, and screw, the smooth, clean working of every plug, piston, and tappet--as, indeed, a life would hang that day. The weather report of the day was not good, but a good half hour before dawn the mechanics had the machines out in line and the pilots were straggling out swaddled in huge leather coats, sheepskin-lined thigh boots, furred helmets and goggled masks. But before they arrived the mechanics had been out a full hour, putting the final touches to the machines, warming up the engines--for it was near enough to winter for the cold-weather nights to make an engine sulky and tricky to start--giving a last look round to everything. The first two Flights went off before dawn, and the third an hour after them. The mechanics walked back into the empty hangars which, after the bustle of the last few days seemed curiously dead and desolate, and then to their waiting breakfasts.