The Computer Age has altered much of our daily life. If you want to hear a fascinating discussion at a moment’s notice, you can instantly click on any of the APS Great Talks Podcasts. If you want to read a news report from another part of the world, you can go to any international news website. If you want to know the tangent of 30 degrees (0.57735026919), you can use any available search engine. But what did people do before the Computer Age? How did 10th grade Trigonometry students take tests without the aid of TI-82s? Enter the ready reckoner.
Think about your average day. If you go to a coffee shop on your way to work, the POS (point of sale) system employed has replaced calculation tables. If this were 1804 and you were on your way to the market, you would have used The graziers' ready reckoner : or, a useful guide for buying & selling cattle; being a complete set of tables, distinctly pointing out the weight of black cattle, sheep, or swine, from three to one hundred and thirty stones, by measurement; together with directions, shewing the particular parts where the cattle are to be measured (636.2 R29r.5). These titles were very important to agricultural life in the early 19th century because they provided a concrete and final measurement for commerce.
Now that you have your coffee—and have traded your swine for some meade—you can start your car, set your GPS, and be on your way. In the 18th century, however, if you were traveling by sea, you would have used An explanation for keeping a ship's traverse at sea by the columbian ready reckoner (Pam. Vol. 76 No. 11). In order to get around without radar or GPS, a ship’s navigator would use these tables to reliably set the course for any journey.
The ready reckoner was also a classroom staple. In the mid-19th century, grammar school children, or their teachers, would have used Southern table book: a new selection of arithmetical tables (510 Pam. no.8). Since calculators of any sort did not exist in the 18th century, children and teachers would need to look up complicated arithmetic values in these tables. Of course, children still had to deal with the right of passage that is the Multiplication Table.
Some of our readers of a certain age can remember a time when they had to look up the square roots of numbers in volumes such as Barlow's tables of squares, cubes, square roots, cube roots and reciprocals of all integer numbers up to 10,000 (510.834 C73b). This particular volume arrived in our collection with the Herman Heine Goldstine Papers (Mss.Ms.Coll.19), proving that even the most erudite of scientists still needed a little help with the small stuff.
Who uses ready reckoners today? I do. As a rare materials cataloger, I encounter maps from all sorts of places that require a Scale Finder. This little gadget allows me to convert almost any scale to the preferred unified scale of measure required by map cataloging rules. Without it, my bibliographic records for maps would be severely lacking. Never underestimate the power of analog technology.