An Account of the Standard Measures Preserved in the Capitol at Rome. By Martin Folkes, Esq; V. P. R. S.

II. An Account of the Standard Measures preserved in the Capitol at Rome. By Martin Folkes, Esq; V. P. R. S. In the Wall of the Capitol is a fair Stone of white Marble, of the Length of 8 Foot 5 Inches English, and of the Breadth of 1 Foot 9 Inches and a half; upon which are inscrib'd the Standards of several Measures with these respective Inscriptions: Piede Ro: Pal. IIII. Onc. XII. Deti XVI. Piede Greco. Canna di Architet. Palmi X. Staiolo Pal. V. Quar. III. Canna di Merca. Palmi otto d' altra misura. Braccio di Merc. Pal. III. d' altra misura Braccio di Tessito di Tela. Curante Lu. Poeto. The Lines that represent these Measures, are cut in the Marble, pretty deep; but as they have, consequently, a considerable Thickness, it is somewhat difficult to be very exact in taking off their Dimensions. I, however, attempted to do it as nearly as I could, by setting the Point of my Compasses 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, by reason the whole Canna is inscribed on the Stone: This I therefore took off, as I presume others have generally done, and then divided it into 10 equal Parts. Afterwards my chief Attention was given to the Roman Foot, as of greater Consequence than the other Measures. They all, however, follow as they occurr'd to me, in such Parts as the London Foot contains a thousand of. The Roman Foot 966 +. This is divided upon the Stone, first into 4 Palms, and then on the upper Part into 12 Unciae, and on the lower into 16 Deti, according to the Inscription. The Greek Foot 10c6 +. This is also divided like the Roman. The Canna of the Architects 73 25. It is divided into 10 Palms, each of which is therefore 73 2½ of the English Foot. The Staiolo being 5 Palms and ¾ is 42 12—. The Canna de Mercanti divided into 8 Palms of another Measure, 6 Foot 6 Inches 5½. The Braccio de Mercanti, divided into 4 Palms of another Measure, 2 Foot 9 Inches 11¼. The Braccio di Tessitor di Tela, divided into 3 Parts, 2 Foot 1 Inch 1¼. The Palm of the Architects is assign'd by Mr. Greaves 732 of the English Foot; and the same is given by Monsieur Picart to the Paris Foot, as 494\(\frac{1}{4}\) to 720; which reduced, becomes 732 + of the English Foot, as before, and as it came out from my own Tryal. The Roman Foot is given by Picart from this very Stone 653\(\frac{1}{10}\) 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 upon this Stone, is assign'd to the Palm of the Architects, as 2040 to 1545; which reduc'd upon the former Measure of the Palm, is 966\(\frac{1}{2}\) 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 Monsieur Picart's Time than it is now, I would make no Difference in the Proportion he has assign'd; but suppose 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 assign'd the Measure of the Roman Foot from Cossutius's Monument, to be 967 of the English, and had preferred that Measure to the others he had taken from the Tomb of Statilius, and the Congius of Vespasian. And I think one can make no doubt, from what has been said, but Cossutius's Foot was the Foot intended to be inscribed upon this Marble; though that Monument is itself now lost: at least when I was at Rome I could get no Intelligence of it, though I made a diligent Enquiry amongst all the People likely to be acquainted with it. Fabretti, in his Work concerning Aqueducts, where he gives the above-mentioned Proportion of the the Palm to the Foot, finds fault with Lucas Pætus, as having made a wrong Calculation of this Proportion in his Book, *De Mensuris & Ponderibus*. True it is, that the Proportion there given by Pætus, does not agree with the Foot upon the Marble, but yet it is no false Calculation, as Fabretti thought; and had he examined Pætus's Book with Care, he would have been sensible this is not the Foot he there contends for, but the Cossutian Foot which Lucas Pætus in his Book disputes against. The Truth therefore is, that he either alter'd his Mind after the writing of that Book, before the Marble was set up; or, more probably, that tho' he had the Care of having these Measures inscribed on the Marble, he was directed by a superior Authority what Measures he was to have engraved; and that accordingly he had, as near as he was able, the Cossutian Foot described for the ancient Roman Foot on the Stone: And that this was the Case, and no Mistake about the Number, as Fabretti supposes, appears not only from the Tenure of his Book, where he condemns Cossutius's Foot, which there appears, but also from his Scheme at the latter End, where he has given what he calls *Scema pedis legitimi*, agreeing with his own Numbers, viz. 12 Inches, whereof 9 make the Palm of the Architects, and also the *Mensura Colotiani & Statiliani pedis*, agreeing with that now inscribed on the Marble. The Colotian is the same Monument as the Cossutian, so called from the Person in whose Possession it had formerly been; and he had before said, p. 5. that according to the Testimony of Philander, the Statilian tilian agreed with it; though Mr. Greaves, who measured both these Feet with great Care, found some difference between them, stating the Cossutian, as above, 967, and the Statilian 972. But by Pætus's quoting Philander, it is plain he had not himself measured the latter; and therefore the Foot, called by him the Colotian and Statilian, is indeed purely the Colotian or Cossutian Foot; and the same has occurred to me also very nearly from my Measure of the Height of the Trajan Pillar, which I find, from the Ground to the Top of the Cimatiurn of the Capitol, to be 115 feet 10 Inches §; and this Height divided by 120, gives very nearly 966 for the Quotient. For the Greek Foot there seems to be no further Mystery, than that it was intended to be made to the Roman in the Proportion collected from Pliny, which is, that 625 Roman Feet made 600 Greek; by which Account the Greek Foot should contain 1007 of such Parts as the Roman contains 967; and the actual Quantity I took off was 1006. III. Observationes nonnullæ notatu non indignæ; Anno 1734. Ab Johanne Frid. Weidler, R. S. S. &c. Vitembergæ factæ. 1. Die xxiii. Januar. A. 1734. iterum apparuit splendida admodum Aurora Borealis, vespere hor. vii. m. 6. Sub septentrionem vilus arcus ater, cum