Category: Engineering & Technology
Practical House, Wagon and Automobile Painter including sign painting, and valuable hints and recipes
“Take a piece of firm, close-grained charcoal, and near one end of it scoop out a cavity about half an inch in diameter and a quarter of an inch in depth. Place in the cavity a sample of the lead to be tested, about the size of a small pea, and apply to it continuously the _bl...