Before passing from the Greek and Roman standards I may add that even higher denominations than the _siliqua_ were expressed by the seeds of plants. The Romans made the lupin (_lupinus_) = 2 _siliquae_ and under its Greek name of _thermos_ (θερμός), it was assigned a like value (_Metrol. Script._ I. 81). In the _Carmen de Ponderibus_ (_Metrol. Script._ II. 16), 6 grains of pulse (_grana lentis_) are made equal to 6 _siliquae_, and a like number of grains of spelt are given a similar value. We next advance towards the East and take up the Semitic systems. We have already had occasion to touch upon that of the Arabs when dealing with the modern Persians. “There can be little doubt,” says Queipo (I. 360), “that the Arab system of weight was based on the grain of wheat.” The _habba_ was their smallest unit. Four _habbas_ are equal to 1 _karat_, the latter of course representing the _keration_ or _siliqua_, and the former the 4 _sitaria_ or _wheat-grains_, which we saw were its equivalent. This is the most ordinary value given to the karat in Makrizi and the other Arabic writers on Metrology, but occasionally we find the karat made equal to only 3 grains, which of course are barley-corns. We saw above that in the Persian system the _nashod_ was formerly divided into 4 _habbi_ of ·048 gram (which is plainly the weight of the wheat-grain), whilst now it is divided into 3 grains each of ·063 which represents the barley-corn, or in other words the Troy grain of ·064 gram. Of course the objection might be raised that as the Arabs had borrowed their higher denominations such as the _dirhem_ (δραχμή) and _dinar_ (_denarius_, δηνάριον), from the Greeks and Romans, and as their standard weight the _mithkal_ is nothing more than the _sextula_ or ⅙ of the Roman ounce, employed in the eastern Empire under the name of _exagion_ (ἐξάγιον, whence comes the _saggio_ of Marco Polo), so too their wheat-corns and barley-corns were not of their own devising, but likewise adventitious. After what we have seen above (p. 166) to be the practice of primitive people in the selling of gold, a traffic in which the Arabs had been engaged for many ages, it would seem hardly necessary to reply to such an argument, but as a more complete answer can be given in the course of the last portion of this enquiry, we shall deal with it in that place.