I have heard that the development of money in Lydia in the first millennium BC was a major development in history. How so? What major benefit would any society have if it used gold and silver coins in everyday transactions, compared to small gold and silver bars? I‘m thinking about the ancient societies where money was developed, not about modern times.
Historically- steam locomotives didn't have them. Diesel electric switchers {those confined to terminal operations } didn't have them .Road units {those operated on the main line} did . Some roads had them only on the engineers side of the forward end of the locomotive .Early street cars and interurban cars didn't have themThe earliest appearance that I've found are on the passenger locomotives made by GM in the 1930's .Perhaps the fact that GM's main business was automobiles caused them to be added to their locomotives as well .FRA rules today would mandate that all locomotives have them
Look at your wiper switch. There is a position on most between off and on marked 'int' or 'var' or delay which stands for intermittent operation. On some it has several positions which control the timing between intervals and on some there is only one position and an adjustable feature for varying the time between operations.
Yes they do.All the forward and rear facing windows have them.They are air powered.
Bullion bars were a bit big and heavy to carry around in your toga pocket.
Coins were more or less standardized, minted by some authority. Both buyer and seller knew the value of a certain coin. Bars and ingots are an unknown. Weight, purity, etc. Anyone could forge bars of gold/copper mix with lowered value.
