There was a custom of _rhōpi_, turn of the scale, or long weight, which increased the legal commercial weight to a customary weight tending towards that of the Alexandrian talent series. In settling the reduction of the Attic money-weight at 100 new drachmæ = 73 old drachmæ, Solon probably fixed on the latter figure in order to make the new talent, = 57·74 lb., have approximately the simple ratio of 4 : 5 with the Greek-Asiatic talent— 4/5 × 72·13 lb. = 57·704 lb. Thus the Roman As being = 5049 grains, 1/100 of the Greek-Asiatic talent, 80 As, = 403,920 grains = 57·7 lb., came to coincide with the Attic monetary talent. 7. THE ARABIC TALENT To the talents and measures of capacity evolved from the feet of the three principal cubits of antiquity, must be added the talent and other measures evolved from the Black foot of Al-Mamūn’s cubit. They have had great influence on the weights and measures of Europe. Al-Mamūn’s cubit was = 21·28 inches, the foot = 14·186 inches. The foot cubed gave a measure of water, the weight of which was the Egyptian Cantar or Cental— 14·1868^3 = 2855 c.i. = 102·92 lb. water = 720,441 grs. This talent was divided in two ways: 1. As the Romans had divided the Alexandrian talent into 125 pounds of 12 ounces, so the new talent was divided into 125 parts each = 5763 grains. This was the Arabic lesser Rotl, its ounce = 480·25 grains. The rotl was also divided in the Greek way into 100 drachms or dirhems = 57·63 grains. 2. Another mode of division was into 100 greater Rotl, thus becoming a Cental of 100 lb. each = 7204·4 grains. This greater rotl was divided, commercially into 16 ounces (Ar. _ukyé_, Gr. _oggia_, L. _uncia_) of 450,275 grains, and uncially for coin-weight into 12 × 12 dirhems of 50·03 grains. Both these dirhems became, like the drachma coin-weights of Greece, the bases of other systems of weight, either at their original weight or at the lower weights to which coins might fall. The Lesser Rotl— 1. With its ounce of 480-1/4 grains would seem to have given rise to the Troy pounds, but it is much more probable that their variable ounces were 10 dirhems of about 48 grains. 2. From 8 of its drachms came the Venetian pound and the German apothecaries’ pound with an ounce of 8 × 57·63 = 461 grains. From the Greater Rotl came— 1. Eight of its ounces of 450-1/4 grains = the Marc of Cologne, its double being the German Imperial pound = 7218 grains; our royal Tower-pound of Plantagenet times being 12 ounces = 5400 grains. The 100 lb. centner of North Germany = 103·1 lb. was almost exactly the same weight as Al-Mamūn’s Cantar. 2. WEIGHTS OF EASTERN EUROPE (see Chap. XV) The Polish pound 16 × 8 dirhems of 48·9 grains „ Russian „ „ „ 49·37 „ „ Austrian „ „ „ 50·6 „