Accession No

6621

Brief Description

calculating ruler, brass, by Thomas Pockley, English, 1650 (c)

Origin

England; Cambridge [attributed]

Maker

Pockley, Thomas Edvardus

Class

calculating

Earliest Date

1650

Latest Date

1650

Inscription Date

(c)

Material

brass

Dimensions

250mm x 35mm

Special Collection

Provenance

Purchased from Tesseract, Box 151, Hastings-on-Hudson, New York 10706, USA, on or before 08/03/2016. Catalogue 102, Spring 2016, lot no. 31.

Inscription

“Tho. Pockley fe. Ao 1650”
“Edvardus“
“W.T. 1761”

Description Notes

Calculating ruler, brass, by Thomas Pockley, English, c. 1650.

Hand-engraved brass calculating ruler. Engraved on one side by Tho. Pockley only, with his inscription at the top. Very finely divided numbered scale of equal parts with transversal interpolations. It is divided in English inches and half-inches, plus the transversal grids, giving divisions to 0.01” on the inch scale, and to 0.005” on the half-inch scale.

On the other side are two very fine grids (perhaps also Thomas Pockley?). One is of equal parts dividing quarter inches to hundredths, or 0.0025”, the other a seemingly nonlinear scale with interpolation. Another two tables are executed in a coarser hand. It seems likely that these are by Edvardus as the engraving style seems to match his handwriting. Tesseract notes both engravers’ work is likely from the same time period as the English numerical shapes being the same classically 17th century ones. There is a complete 9x9 grid giving a full multiplication table, and a surveying table of “P. R. Lin”. Tesseract states this table gives the number of square Lin(ks) as a function of P(erches) and R(oods).

Tesseract suggest the maker is Thomas Pockley, student at Cambridge Trinity College. The catalogue states:
“We find various traces of him, entered as a subizar (a sort of work-study position in relief of tuition payment) 1645/6, admitted scholar 1649, receiving £5 that for “haveing done something w’ch is usefull in the Library,” B.A. 1649/50, Fellow 1650, M.A. 1653, receiving three years’ leave to travel (and with traveller’s expenses!) in 1651. In 1654 the important physician and naturalist, Henry Power, writes to Pockley on the joy of having studied at Cambridge with all the wide-ranging discourses “Physicall mathematicall & Anatomicall.” And in 1658 we find John Ray planning a series of chemical experiments with Pockley. He is recorded as Tutor at Trinity in 1661, just eight years before Isaac Newton (who had also been a subsizar there) was first recorded as Tutor.”

In good/fair condition. Complete. Some wear to brass.

References

Events