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Coin and Currency in [No. 9, new series. 



and silver, leaving ses to the Senate. This body retained the 

 remnant of their mint powers until the time of Gallienus, when 

 the complete control of the entire currency of the Empire was 

 monopolised by the Emperor. There were at this time subordinate 

 mints in Spain, Gaul and other parts of the Empire, but the coin 

 struck was Roman. In the western countries the issue of other 

 coins than the Roman was given up in the first century of the 

 Christian Era ; in the East the Roman coin did not become the 

 sole currency until the time of Gallienus. 



The earliest coins were cast. We have many specimens of 

 Roman pieces of money with marks at the edge where they were 

 separated from the remainder of the cast. In one case in the 

 British Museum there are several Roman ases still joined together. 

 The next step was to cast the piece first and strike it afterwards. 

 While this was the usual process, coins of the same denomination 

 and value migfht vary a good deal in breadth and thickness ; and 

 in many extant specimens of the more ancient coins we find this 

 to be the case. In the present day the dies for striking coin are 

 made of steel, tempered by heating to a certain degree and 

 plunging into water cold in an inversely proportional degree. 

 Thus, a dull red heat and water at 34° (Fahrenheit) — cherry red 

 heat and water at 50° — orange red and water at 80° all effect 

 about the same amount of tempering, though a greater degree of 

 real hardness is produced by the use of cold than of warm water. 

 A red heat and water at 45° of Fahrenheit form the most desirable 

 combination of means for hardening coining-dies. 



From what I have said above, it is evident that the most import- 

 ant duty of a Mint is the examination into the fineness of gold 

 and silver about to be converted into current coin. The process 

 is technically called " assaying." 



In the English Mint, the assay of both silver and gold is per- 

 formed by cupellation : in the French Mint the latter only. The 

 quantity of metal upon which the testing experiment is performed 

 is very small, but is called the " assay pound." In the case of 

 gold it is divided into 24 carats,* and each carat into 4 carat 



* ^ carat gr. = 7| grs. Troy. The weight of diamonds is estimated 

 in carats, carat grains, eighths, sixteenths and thirty-seconds. About 

 150 carats make a Troy ounce, or 480 grains. (Brande.) 



