`` how the devil have they managed to cut down a hundred trees- '' `` they are cutting down another , over there , '' gerry piped up , and looking temeraire saw not a heavy-weight but three light-weight dragons instead , who were using a kind of saw which was little more than a long toothed chain with one end run around a wheel , which two of them turned rapidly by a crank while the third steadied the tree ; the trunk was being torn through at extraordinary speed , and when it had been reduced to only a thin sliver , a heavy-weight was waved down ; when she had seized it , several men chopped at the remaining portion with axes until she was able to break it off and carry it away .