Dutch anonymous instruments

Title page of Dierick Ruyter's book, published in 1631, on the use of the Pleynschael.

Dutch wooden pleinschaal

In the Netherlands the 2-sided plain scale, as shown above, was preferred to the more common Gunter navigational scale. This unsigned example (314x33mm) is almost identical to the one in the Boerhaave Museum in Leiden. Probably dating from early to mid 19th century.

____________________

[1] Otto E. van Poelje; Journal of the Oughtred Society: The Sliding Gunter-Versions for Navigation at Sea.

[2] Also see Holm's sliding Gunter.

[3] W. F. J. Morzer‐Bruyns; A history of the use and supply of the Pleynschael by instrument makers to the VOC. International Journal of Nautical Archaeology: 1982, Vol. 11, No. 4, p.293-296.

[4] Museum Boerhave have two nautical rules in their collection; one unsigned and the other one made by Hulst van Keulen.

Early brass protractor with floral motifs.

Small semi-circular brass protractor graduated in 1/2 degrees with hand-engraved numbering. Possibly Dutch but could just as well be German. Probably dating from around 1700 or even a bit earlier. Base measures 102mm, height 67mm.

Simon Stevin's booklet De Thiende ('the art of tenths'), first published in Dutch in 1585.

Dutch brass scale rule 159x25.5mm.

There are 3 transversal scales on the front face;

1. Rhijnl: geom: duijm (Rhineland geometric inch)

1. Rhijnl: werk duijm (Rhineland work inch)

1. Frans: Kon: duijm (French Royal inch)

The reverse face has scales of equal parts related to the French Royal inch. B: 1/12th scale, C: 1/16th scale, D: 1/24th scale, E: 1/32nd scale.

The Rhineland geometric inch is not a tenth part of a foot as one might think, but the equivalent of 1/100th of a Rhineland roede (3.767 meters). The idea of dividing measures into decimal fractions came from Flemish mathematician Simon Stevin in his work De Thiende (the art of tenths) first published in Dutch in 1585. The first Dutch surveying textbook by Jan Pieterszoon Dou and Johan Sems 'Practijck des Lantmetens' published in 1600, helped popularise the use of decimal fractions in the Netherlands surveying community.

____________________

[1] Lührs, W.: Ein Beitrag zur Geschichte der Transversalteilungen und des Nonius, Z.f.V. 1910. pp.177-191. [Internet Archive]

[2] Otto van Poelje; Diagonal Scales - A Critical Assessment, MIR 36, June 2004.

[3] Feldhaus; Geschichte des Technischen Zeichnens 1960, p. 49.

[4] Goldstein, B. R.; Levi ben Gerson: On Instrumental Errors and the Transversal Scale, Journal for the History of Astronomy, Vol. 8, 1977, pp.102-112.

[5] Fockema Andreae, S.J.; De Rijnlandsche roede : geschiedenis eener oud-Nederlandsche landmaat, Tijdschrift Koninklijk Nederlandsch Aardrijkskundig Genootschap, 1932, pp. 635-657.

Cosmographicus liber Petri Apiani mathematici studiose collectus, 1524 [Smithsonian Libraries]

3 Dutch brass protractors

The illustration in the left hand margin from Apian’s Cosmographia illustrates the units of measure, based on human body parts, common in the 16th century.

Above are three unsigned protractors, all dating from around 1750 to 1800 with transversal scales on the base. These transversal scales, or diagonal scales, have no apparent real world unit of measure. The current hypothesis suggests that they were used to solve geometrical problems (often a triangle), i.e. a figure would be constructed on paper and the unknown parameter, either a distance or an angle, was simply measured from the drawing.

Ball-head compasses. Around 1820, after discussions with the director of the military school in Delft, Bayens was the first to fabricate the 'Delftsche passer', or Delft compass.

Dutch drawing set #1

Unsigned, early 19th c.

Dutch drawing set #2

Unsigned, early 19th c. A small brass plaque with the name 'Brocx' possibly indicates the original owner.