Measuring instruments

Calibro These curved-arm bronze callipers are exactly the same as those still used today, and were utilised for the measurement of the thickness of objects, including protruding decorative elements. The exterior facing of the arms of this example features an engraved heart-shaped leaf motif showing traces of niello-ing. Bibliography: V. Sampaolo, Gli oggetti, in Pompei 1748-1980. I tempi della documentazione, Roma 1981, p. 205 Weight for plumbline Weights for plumblines were of generally conical shape, more or less flattened in the manner of a pear or acorn, and well-turned on the lathe. They were essential tools for builders and metalworkers for tautening the plumbline when tracing precision vertical lines or, used in conjunction with a level, horizontal planes. Bibliography: V. Sampaolo, Gli oggetti, in Pompei 1748-1980. I tempi della documentazione, Roma 1981, p. 204 Pair of compasses This extremely simple precision instrument has been in use since ancient times and with its hinged conical or laminar arms has left us many traces on the painted walls. It was used to prepare the patterns for the repeated plant volutes in the painting of the background to horizontal friezes, or for the linked circles which made up the Hellenistic rosettes", or for the medallions later painted with landscapes, busts, still-lifes etc. In a number of cases, once the painted top-coat had fallen away along with the subject-matter, all that was left was the circular engraving. Bibliography: V. Sampaolo, Gli oggetti, in Pompei 1748-1980. I tempi della documentazione, Roma 1981, p. 203 Folding ruler This modulus is equivalent to the Roman unit of linear measurement, the foot, which was about 29.45 cm. It is made of two hinged arms which can be held open thanks to the close fit with a side piece attached to hinges. On the face of the instrument, we can see clearly two engraved dots which mark out the submultiples of the foot: the inch of 2.45 cm each, and the digit of 1.84 each. Bibliography: V. Sampaolo, Gli oggetti, in Pompei 1748-1980. I tempi della documentazione, Roma 1981, p. 204 Set-square This set-square is made up of two right-angled arms, one of which has a supporting base, and was used to check the perpendicular nature of both vertical and horizontal surfaces and lines. The fact that the ends of the arms are shaped has led to the opinion that they were used for tracing profiles for the frames of painted decorations, while those in plaster generally used moulds and mortar-boards. Bibliography: V. Sampaolo, Gli oggetti, in Pompei 1748-1980. I tempi della documentazione, Roma 1981, p. 205

Fonte: MANN
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