This operation is frequently carried on in connection with amalgamated surfaces over which the metal is passed to still further attract and concentrate the ore. An endless apron travelling over cylinders is sometimes employed, composed of slats the surface of each of which is coated with an amalgam, and on this belt the powdered ore is spread thinly and carried forward. The vibrations of the belt tend to shake and distribute the ore particles, the amalgam attracts them, the refuse is thrown off as the belt passes down over the cylinder, while the ore particles are retained and brushed off into a proper receptacle. _Amalgamators_ themselves form a large class of inventions. They are known as electric, lead, mercury, plate, vacuum, vapour, etc. By the help of these and a vast number of other kindred inventions, the business of mining in all its branches has been revolutionised and transformed, even within the last half century. With the vast increase in the output of coal, and of ores, and the incalculable saving of hand labour, the number of operators has been increased in the same proportion, their wages increased, their hours of labour shortened, and their comforts multiplied in variety and quantity, with a diminished cost. The whole business of mining has been raised from ceaseless darkness and drudgery to light and dignity. Opportunity has been created for miners to become men of standing in the community in which they live; and means provided for educating their children and for obtaining comfortable homes adorned with the refinements of civilisation. _Well boring_ is an ancient art--known to the Egyptians and the Chinese. Wells were coeval with Abraham when his servant had the celebrated interview with Rebecca. “Jacob’s well at Sychar--the ancient Shechim--has been visited by travellers in all ages and has been minutely described. It is nine feet in diameter and one hundred and five feet deep, made entirely through rock. When visited by Maundrel it contained fifteen feet of water.”--_Knight._ Some kind of a drill must have been used to have cut so great a depth through rock. The Chinese method of boring wells from time immemorial has been by the use of a sharp chisel-like piece of hard iron on the end of a heavy iron and wood frame weighing four or five hundred pounds, lifted by a lever and turned by a rattan cord operated by hand, and by which wells from fifteen hundred to eighteen hundred feet in depth and five or six inches in diameter have been bored. This method has lately been improved by attaching the chisel part, which is made very heavy, to a rope of peculiar manufacture, which gives the chisel a turn as it strikes, combined with an air pump to suck up from the hole the accumulating dirt and water. Artesian wells appear to have first been known in Europe in the province of Artois, France, in the thirteenth century. Hence their name. The previous state of the art in Egypt, China and elsewhere was not then known.