of alloy makes the latter less easy to work up into jewellery). I allude to this here because we shall find in the course of our enquiry that most of the errors into which metrologists have fallen, are the consequence of their failing to recognize the great gulf which is fixed between the habits and ideas of a primitive community, slowly evolving principles which are now part and parcel of the common heritage of civilization, and an era like our own, when all progress is effected by the development and application of scientific principles long since discovered. Electrum was thus coined on the same standard as silver, one _talent_, one _mina_ and one _stater_ of electrum being consequently equal to ten _talents_, ten _minae_, or ten _staters_ of silver. The weight of the electrum stater in each district would depend therefore on the standard which happened to be in use there for silver bullion, or silver in the shape of bars or oblong bricks, the practice of the new invention of stamping or sealing metal for circulation being in the first place only applied to the more precious of the two metals, electrum representing in a small compass a weight of uncoined silver ten times as bulky and ten times as difficult of transport. The invention was soon extended to pure gold and silver, and there is good reason to believe that by the time of Croesus (568-554 B.C.) both these metals were used for purposes of coinage in Lydia. _The Greeks begin to coin money._ The clever Greeks of Asia Minor, who formed the portal through which so many of the arts of the East reached the Western lands, were not slow to adopt, and by reason of their superior artistic taste to improve, the great Lydian invention. To the Ionic cities such as Phocaea and Miletus we must probably ascribe the credit of substituting artistically engraved dies for the rude Lydian punch-marks, and at a somewhat later period of inscribing them with the name or rather the initial of the people or potentate by whom they were issued. The official stamps by which the earliest electrum staters were distinguished from mere ingots consisted at first only of the impress of rude unengraved punches, between which the lump or oval-shaped bullet of metal was placed to receive the blow of the hammer. Subsequently the art of the engraver was called in to adorn the lower of the two dies, which was always that of the face or _obverse_ of the coin, with the symbol of the local divinity under whose auspices the currency was issued. As our object is to deal with coins from the point of view of metrology, the short summary here given of the genesis of the art of coining will suffice for our purposes. _Weight standards._ “Silver was very rarely at this early period weighed by the same talent and mina as gold, but, according to a standard derived from the gold weight, somewhat as follows:—