Full Details

Name and Model Number Brass Sector
Country of Origin UK
Date of Manufacture ~ 1683
Front Scales Unusual sectoral scales, possibly relating to the science of fortification
Back Scales Normal sectoral scales
Scale Length 6” on each leg
Type of Rule Other
Construction Brass
Area of Use Generic
Comment Apart from the name of Charles ll Rex and the date 1667, there are three other names and dates
shown on the front of this delightful brass sector which also has a third hidden arm to enable
a full triangle to be set up. These are: Tessini with a date of 1630, Prearo Sardi dated 1683
and Count Pagan dated 1650. Two of these three are known to have written books on fortification.
Count Pagan’s book “Les Fortifications de Monsieur le Compte de Pagan” was published in Brussels
in 1668, while Francisco Tensini published his “La Fortificatione Guardia Diffesa …” in Venice in 1624.
Nothing has yet been found relating to Sardi, however this would appear to be the sector which
carried the scales to enable the calculations on fortification science described in these books to be
realised, as well as the more normal sectoral calculations of these times. A really delightful and
extremely rare calculator carrying some extraordinarily early dates.
Rarity RRRR
Donor Collection of an English gentleman
Match Number 89

RR = Rare -- 1 of 25 collectors has one; it may take a year to find an example in the marketplace.   
RRR = Very rare -- only very few known to collectors; may take several years before one comes up for sale.   
RRRR = Extremely rare -- a museum piece; unlikely that an example will ever come up for sale.