Maker and Role
There are 2 main parts. The first is a rectangular piece of metal (95 mm x 260 mm) with one rounded end. Rectangle has cm. measured on one side and inches on the other. It also has a table with Rate of Descent in Feet/minute against glide-path angle. The reverse side has a number of curved lines labelled from 70-350. This rectangle slides through the second part of the instrument and it bulges at the sides to leave room for a circle. There is a smaller metal disc attached on top as well as a rectangular piece of plastic (transparent with a line through the centre). These top 2 parts rotate. Both circles have multiple number scales on them. The reverse of this smaller piece has a clear plastic circle enclosed in metal. The plastic has red lines radiating out from the centre and labelled in degrees. Contained in brown, leather case. Rectangular, although one end is slightly wider than the other. The front near the bottom has the Mercator calculator logo (on stylised image of the instrument with an "M" and an "L" beside it). There is a seam one third of the way up. Above that seam is a rectangular plastic window. There is a snap in the top right corner. When open, the corner folds back to reveal a compartment with 4 elastic loops. There is a further compartment the full size of the case, opening at the top.
-3 Paper booklet called "Instructions for 'Mercator' Computer". Also on the cover "Type B4 & B4-HS". The Mercator logo and "Mercator Computer / Langestraat 55, Kamer 9 / Alkmaar (Holland)".
Processed Material/Metal/Alloy/Steel/Stainless Steel
Signature/Marks and Type
Mercator Computor / B.4 / Mercator / Computor / Alkmaar - Holland / Copyright by Mercator Printed
MC / Mercator / Alkmaar - Holland Embossed
Mercator. Computer Mercator, Case, Booklet, 2004.416. The Museum of Transport and Technology (MOTAT).