COMPARATIVE METROLOGY. 381 



more than 400 feet is in reality over 1000. Taking the relations 

 of the rubbio into account, and also the subdivisions of the pezza, 

 there can be no reasonable doubt that the latter does really re- 

 present the jugerum ; but in such a matter an error of Niebuhr's 

 is worth pointing out. A little farther on he says that no one 

 can blame him for not having sooner known that the pezza was 

 not any piece of land, but one of a particular size. No one will 

 blame him probably, and yet it is only what must have been 

 known to a great number of persons. In 1760 Cristiani pub- 

 lished a work which I only know by a table quoted in Diderot's 

 Encyclopedic (Art. Arpent), in which in the space of a few lines 

 the values of the pezza and the jugerum are both given (T am 

 at least sure as to that of the former), much more accurately 

 than by Niebuhr. The same table, or the materials from which 

 it was compiled, have probably found their way into many other 

 works of reference. Niebuhr tells Savigny that rubbio is also 

 a measure of wheat of about 640 Roman pounds weight, so called 

 because it was the usual amount of seed for the corresponding 

 measure of land. But he has not noticed the curious circum- 

 stance that the rubbio of oats and that of wheat differ, and that 

 the measure (for it is a measure and not a weight) is less in the 

 case of oats, although probably in Italy as here a much larger 

 quantity of seed is used for it than for wheat. Niebuhr has also 

 remarked that in his opinion the stajolo, which is the smallest 

 square measure, is derived from sextarius, so as to signify such 

 measure of land as would require a sextarius of seed, admitting 

 however that the stajolo must have grown smaller since it ob- 

 tained its name. Greatly smaller it must have grown, for a 

 sextarius to the stajolo would be at the rate of about 50 bushels 

 to the English acre. It is almost incomprehensible that Niebuhr 

 should not have seen that stajolo can be nothing else than sta- 

 diolum, whether or no the latter word occurs in dictionaries. 

 It is moreover properly a linear measure. 



Although square measures have strictly no definite form, yet 

 one form which may be called the normal form is generally 

 indicated by their subdivisions if not by historical evidence. 

 In the case of the jugerum both concur in showing that it was 

 contemplated as a double square, and probably in early times 

 it never existed in any other form. That of the fundus of 

 7 jugera is not I apprehend so distinctly marked, though it can 



