Oilstone
A hard, gritty stone upon which oil is used for sharpening tools. The Arkansas and Washita stones are the two principal American grades, the former being the harder and finer. A mixture of one part alcohol and two parts glycerine will be found a much better lubricant for the oilstone where small tools, such as watchmakers use, are sharpened, than will the ordinary oils used. Oilstones often become so saturated with oil as to be almost useless and are often abandoned on this account. Such a stone, if soaked in benzine for a few days, will come out as good as new.