of Dies and Medals for Coinage. 121 



letters by its lateral spread, at the same time that the coin re- 

 ceives the blow of the screw-press. 



Coins are generally completed by one blow of the coining- 

 press. These presses are worked in the Royal Mint by ma- 

 chinery, so contrived that they shall strike, upon an average, 

 sixty blows in a minute ; the blank piece, previously properly 

 prepared and annealed, being placed between tlie dies by part 

 of the same mechanism. Of these presses, and of the other 

 machinery and operations used and carried on in the Mint, 

 an excellent account, with illustrative engravings, has been 

 given by Mr. Mushet, in the supplement to the Encyclopaedia 

 Britannica. 



The number of pieces which may be struck by a single die 

 of good steel, properly hardened and duly tempered, not un- 

 frequently amounts at the Mint to between three and four 

 hundred thousand, but the average consumption of dies is of 

 course much greater, owing to the different qualities of steel, 

 and to the casualties to which the dies are liable : — thus, the 

 upper and lower die are often violently struck together, owing to 

 a fault in the layer-on, or that part of the machinery which 

 ought to put the blank into its place, but which now and then 

 fails so to do. This accident very commonly arises from the 

 boy who superintends the press neglecting to feed the hopper of 

 the layer-on with blank pieces. If a die is too hard, it is apt 

 to break or split, and especially subject to fissures, which run 

 from letter to letter upon the edge. If too soft, it swells, and 

 the collar will not rise and fall upon it, or it sinks in the centre, 

 and the work becomes distorted and faulty. He, therefore, 

 who supplies the dies for an extensive coinage has many 

 casualties and difficulties to encounter. There are eight presses 

 at the Mint, frequently at work for ten hours each day, and I 

 consider that the destruction of eight pair of dies per day (one 

 pair for each press), is a fair average result, though we much 

 more frequently fall short of than exceed this proportion. It 

 must be remembered, that each press produces 3600 pieces 

 per hour, but, making allowance for occasional stoppages, we 

 may reckon the daily produce of each press at 30,000 pieces ; 

 the eight presses therefore will furnish a diurnal average of 

 240,000 pieces. 



