|Name and Model Number||Fowler - - - Mackay |
Paper & Board Calculator
|Country of Origin||England|
|Date of Manufacture||unknown|
|Front Scales||Fixed Outer Scale (Oz per Sheet); Moveable Middle Scale (Sheets per CWT); Moveable Inner Scale (Lb per Ream 480”s)|
|Scale Length||Short scale ~ 10” (25 cm)|
|Type of Rule||Watch Type|
|Construction||Metal with paper scales , glass window, plastic back|
|Area of Use||Other|
|Comment||Single sided pocket watch calculator with two stems to rotate inner paper scales and celluloid cursor.
Outer paper scale fixed.
Made special for F. Mackay & Co. All three scales are logarithmic short scales calibrated for different measures.
Blankenhorn and De Cesaris Model 4MMP1.
|Donor||Collection of Dr. Paul J. Tarantolo Jr.|
(Click Picture for Details)
|In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen|
|(1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD.|
|• RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace.|
|• RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale.|
|• RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale.|