Bead Calculator

Bead calculator

Source: Ashmolean Museum, Accession No. 1685 A no. 453

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Dimensions (closed): Height 97 mm; Width 65 mm; Thickness 20 mm

Desciption. Consists of two shallow boxes, apparently of pine. Originally the boxes were joined at their longer sides by simple metal hinges, now broken, and were fastened when closed by a hook-and-pin catch. Each of the boxes has six stiff wires running horizontally across it at regular intervals, with the ends set through the wooden frames on either side. The wires of the left-hand box are strung with metal beads, ten to each wire, except the lowest, which has four. The right-hand box is similar, except that the top four rows contain ten beads each, with a row of four and another of two beneath. A label bearing the number 72 is pasted on the outer vertical frames of each box, and another, with the inscription Numerical table of the Chinese, is pasted across the back of each box. In the lower right-hand corner of the right-hand box there is a hole through the transverse frame, possibly for carrying or suspension; the hole is worn smooth and funnel-shaped, which suggests long use. When the instrument is closed there appears to be a W or M scratched across the middle of the two outer frames.

Commentary. This instrument is undoubtedly a Russian schety or counting-frame, which may have been brought to England by the elder Tradescant after his trip to Archangel with Sir Dudley Digges in 1618. The schety probably first came into use in the mid-sixteenth century. Its origin is obscure, but it may have been indigenous to Muscovy. If a date of 1618 is accepted for the Tradescant schety then it is the oldest extant specimen. The Tradescant schety also pre-dates descriptions of the object in either Russian sources or the accounts of foreign travelers, and is therefore of considerable historical interest. Particularly noteworthy is the fact that it has ten-bead rows. Many of the descriptions of the schety in Russian manuscripts indicate nine-bead rows, and the historian of the schety, Spassky, suggests that the change to ten-bead rows reflects the transition from the old Greek-style alphabetical numerals to modern numerals. The 1656 description of the instrument as "Indian" may have arisen because the younger Tradescant and his collaborators were unaware of its true provenance, and simply gave it a suitably vague and exotic origin. The term "Indian" was used to describe artefacts of widely differing origin in the catalogue. Later cataloguers were clearly not satisfied with the Indian ascription and chose rather Japanese (1685) or Chinese (1836), presumably because they were aware of analogous instruments from those cultures.

Museum Id. No:

1656 p. 54: Beads strung upon stiffe wyres, and set in four-square frames wherewith the Indians cast account
1685 A no. 453: Abacus Japonicus, in quo rationes colliguntur per globulos stanneos perforatos filo ferreo consertos, stylo item ferreo hinc inde mobiles.

Credits: Abridged from W. F. Ryan, 'Bead calculator', in Arthur MacGregor (ed.),Tradescant's Rarities: Essays on the Foundation of the Ashmolean Museum (Oxford, 1983), no. 193, p. 253.