had to be very accurate; it was he who kept a careful balance on the log and guided the long saw, who kept the cuts straight or curved as required, and who estimated the width of the planks. He was the man in charge of the operation, and it wasn't uncommon for nicknames such as 'William Top-sawyer' to be common currency in country areas. Saw pits were a crucial component of shipbuilding, for which planks of wood were necessary for the construction of all classes of vessels. The logs of wood to be sawn were placed over a pit on planks of wood called "dogs" in naval jargon. The senior sawyer stood on top of the plank. The junior one had to go into the pit, which was often partially filled with water, with sawdust constantly 'raining down,' so he stood in a layer of sawdust as a result. One theory of the origin of the terms 'top dog' and 'underdog' is that they come from saw pit work practices (however, others cite documentary evidence that these terms more likely arose from dog fighting). Cutting from underneath a suspended log is sometimes called "underbucking". Ten foot logs were sometimes sawn into boards except for about the last two inches. In this way the boards could be more easily handled; then the boards were separated by cutting off the end of the log. Up to 200 boards a day could be produced with water-driven power sawing, compared to the 12 or so a day by two men in a saw pit. A saw pit could, if circumstances demanded, be worked by a single person, with the end of the saw being weighted with a stone or some other weight, and then raised and lowered by the sawyer. Views of the Kennox estate saw pit History of the saw pit A very early water driven Roman sawmill was in use in Hierapolis, the Hierapolis sawmill. Sawmills may well have been developed in the medieval period, as one was sketched by Villard de Honnecourt in c. 1250. There are claims that they were introduced to Madeira following its discovery in c. 1420 and spread widely in Europe in the 16th century. The 'modern' sawmill was invented or perfected by the Dutchman Cornelis Corneliszoon (1550–1607) who applied a pitman arm onto a wind mill, which converted a turning motion into an up-an-down sawing motion.