The invention of balance scale

People have always needed to compare weights of animals, grain, money etc. They invented a balance scale on which two pans were suspended, one from each end of a balance horizontal bar. They then put something of known weight on one pan and the unknown on the other pan.

The word balance comes from the Latin “bi lanx” that means double pan. The balance scale essentially consists in a couple of pans suspended from a yoke; the latter is suspended in the middle point between the points in which the dishes are suspended.

The fulcrum or the middle point is where the equilibrium occurs. A teeter-totter is an example of a balance scale. Metal scales dating to 5000 BC have been found in archeological digs.

Balance scales were in use by 4000 BC in both Egypt and China. The ancient Egyptians are thought to have developed the first known weighing instruments, which they probably used to measure gold. They were able to accurately measure to a small fraction of an ounce by 1500 BC.
The invention of balance scale

The invention of windmill

The power of the wind was well recognised in antiquity when people took advantage of its to propel ships. Sailing ships using wind power to drive their ships by 3000 BC. Some historians believed that the windmill had its origin in Tibet or China,where wind-driven prayer wheels that rotated on a vertical axis were common.

The earliest known wind powered grain mills and water pumps were used by the Persians in A.D. 500-900. Communities in Persia were mounting small sails of reed mats, woven palm fronds, and occasionally slats of wood onto vertical shafts extending through the roofs of buildings. The sails spun horizontally turning the vertical shaft to provide grinding power below.

In China in the 8th century AD, windmills were apparently employed for helping to haul canal boats past canal locks but were not used for grinding grain.

Around AD 1100, the ‘Mediterranean’ windmill began to appear in Italy. Massive, two story stone building were mounted with vertical sails and it was connected to a vertical shaft that drove the mill grinding stone below. Windmills were used in Holland in the 15th century for pumping water over the dikes.

The first windmill manufactured in the United States was designed by Daniel Halladay, who began inventing windmills in 1854 in his Connecticut machine shop.

By the early nineteenth century steam engines had begun to replace windmills as the preferred power source for grinding and for industrial uses.
The invention of windmill