Complete the summary below.
Choose ONE WORD ONLY from the text for each answer.
Write your answers in boxes 37-40 on your answer sheet.
The most basic method used by many miners began with digging some 37.  out of a river and hoping it might contain gold. Small amounts were put in a pan with water. The pan was spun round, causing the liquid and less heavy contents of the pan to come out. Gold dust, which weighed more, remained in the pan or, if the miners were very lucky, there might even be some 38.  too. It was, however, a very laborious method.
The rocker was also used. A miner would put some earth and rock into the higher end, together with some water. He would then shake the rocker. Larger stones stuck in the 39. , while gold dropped to the bottom. Unfortunately, the rocker was not designed to catch what was called flour. However, a process was introduced involving 40.  to ensure no gold was washed out in the water.