VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. 75 



cult to be very exact in taking off their dimensions. Mr. Folkes however did 

 it as nearly as he could, by setting the point of his compasses in the middle of 

 the cross lines, that are drawn to determine the beginnings and ends of the 

 measures. The palm of the architects is easier to give than the others, be- 

 cause the whole canna is inscribed on the stone : this he therefore took off, 

 and then divided it into 10 equal parts. Afterwards his chief attention was 

 given to the Roman foot, as of greater consequence than the other measures. 

 They all however follow, a^Hhey occurred to him, in such parts as the London 

 foot contains 1000. 



The Roman foot 966 +. This is divided on the stone, first into 4 palms, and 

 then on the upper part into 12 unciae, and on the lower into 16 deti, accord- 

 ing to the inscription. 

 The Greek foot 1006 -|-. This is also divided like the Roman. 

 The canna of the architects 7325. It is divided into 10 palms, each of which, 



is therefore 732-i^ of the English foot. 

 The staiolo, being 5 palms and \, is 4212 —. 

 The canna de mercanti, divided into 8 palms of another measure, 6 feet 6 



inches 4-1-. 

 The braccio de mercanti, divided into 4 palms of another measure, 2 feet 9 



inches -14. 

 The braccio di tessitor di tela, divided into 3 parts, 2 feet 1 inch^x- 



The palm of the architects is assigned by Mr. Greaves 732 of the English 

 foot ; and the same is given by M. Picart to the Paris foot, as 4944- to 720 ; ' 

 which reduced, becomes 732 -|- of the English foot, as before, and as it came 

 out from this trial. 



The Roman foot is given by Picart, from this very stone, 653 ,V of such 

 parts, as the Paris foot contains 720 ; that is, by reduction, 967 + of the 

 English ; and the same by Fabretti, who also measured it on this stone, is 

 assigned to the palm of the architects, as 2040 to 1545 ; which reduced on the 

 former measure of the palm, is 966-^ of the English foot. These measures 

 come out as near as the nature of the standard can possibly allow ; and as it was 

 somewhat fresher in Picart's time, than it is now, Mr. F. would make no dif- 

 ference in the proportion he has assigned ; but supposes the Roman foot on 

 this marble was intended to be such a one, as should contain 967 parts of the 

 English very nearly, 



Mr. Greaves had long before assigned the measure of the Roman foot from 

 Cossutius's monument, to be 967 of the English, and had preferred that mea- 

 sure to the others he had taken from the tomb of Statilius, and the Congius of 



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