A method to create steel balls by inserting the sphere in a hollow cylinder and rotating the ball with two cylinders covered with leather on the top.

Device Turning Steel Sphere Balls

A method to create steel balls by inserting the sphere in a hollow cylinder and rotating the ball with…

"Galvanism is the branch of electric science to which an experiment by Galvani gave birth. His wife, who was making soup from frogs, put them in proximity to a charged electrical machine. On touching them with a scalpel their legs became greatly convulsed. He came to the erroneous conclusion that animal electricity existed in the nerves and muscles of frogs, etc. His contemporary Volta inferred that the metals took the active part in producing the contraction, and the electricity was due to their contact. In 1800 he first described and constructed what has since been called the Voltaic pile."—(Charles Leonard-Stuart, 1911)

Galvanic Battery

"Galvanism is the branch of electric science to which an experiment by Galvani gave birth. His wife,…

"Sand Blast is one of the most wonderful uses of sand, by means of which glass, stone, metals, or any other hard substance may be cut or engraved. If a stream of sharp sand be let fall from a high box (as high as the ceiling of a room) through a tube on to a plate of glass held under it, the sand will cut away little grains of the glass till at length the whole surface will be cut or scratched and it will look like ground glass. If, instead of cutting the glass all over, it is wanted to engrave a pattern or figure on it, the workman has only to cover the parts of the glass which he does not want cut with a stencil plate made of leather, rubber, paper, wax, etc., for the sand will not cut any soft substance. Metals and stones may also be cut by means of the sand blast, which will not only scratch the surface, but will cut it away to any depth."—(Charles Leonard-Stuart, 1911)

Sand Blast Apparatus

"Sand Blast is one of the most wonderful uses of sand, by means of which glass, stone, metals, or any…

Troy weight is a system of units of mass customarily used for precious metals, black powder, and gemstones.

Troy Weight

Troy weight is a system of units of mass customarily used for precious metals, black powder, and gemstones.