much valuable information) that “with the Egyptians the didrachm is the monad. But the monad is the source of production of all numeration.” As two drachms were 135 grs., it is evident that it is the kat of 140 grs., and not the uten of 1400 grs. which the Egyptians themselves regarded as the basis of their system[297]. Mr Flinders Petrie from the weights of 158 specimens found in the ruins of Naucratis, which range from 136.8 grains to 153 grains, concludes that there were two distinct kat units, one weighing 142 grs., the other 152 grs. But until some literary evidence is forthcoming for the existence of this second and heavier kat[298], we must suspend our judgment. It is perfectly possible that such existed, being used for some purpose different from that of the kat of 140 grains. For instance it might have been used specially for copper owing to a desire to make certain adjustments between silver and copper, but this is of course mere conjecture. It is worth while here to see the method by which those who believe in a scientific system of Egyptian origin obtain their unit. Signor Bortolotti (_Del primitivo cubito Egizio_) thinks that the uten of 1400 grains is exactly the ⅟₁₀₀₀ part of the weight of a cubic cubit of Nile water, the cubit in question being not the ordinary royal cubit of 20·66 inches, but a measure which he calls the primitive Egyptian cubit of 19·71 inches in length. Signor Bortolotti also suggests that the standard uten of Mr Petrie’s heavy system was 1486 grains, being the ⅟₁₅₀₀ part of the weight of a cubic _royal_ cubit (20·66 inches) in Nile water. But as I have just pointed out the evidence is in favour of the kat being the original unit rather than the uten. Besides if the Egyptians obtained their system for the first time by the scientific process, we ought naturally to find some of those larger units such as the talent and mina, which are found in Egypt at a later epoch. But as we have seen in the case of Greeks, Hebrews, Chinese and Hindus, everywhere weight systems begin with a weight for gold, and this is naturally a small unit.