Then they fell to work on the new airplane, applying themselves like beavers.  All three boys had had the splendid benefits of manual training when they were in the public schools, and knew how to handle every machine they had set up.  In addition to this, Paul and Bob were first-class amateur machinists, as their courses of engineering in Clark Polytechnic embraced the use of metal-working appliances of the latest design, as well as wood-working machinery, and they could have operated other machines had they needed them.