Periodic Table |
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| What is the Periodic Table Showing? | Periodicity |
The INTERNET Database of Periodic Tables
There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D. The database holds information on periodic tables, the discovery of the elements, the elucidation of atomic weights and the discovery of atomic structure (and much, much more).
| Year: 1992 | PT id = 1045, Type = formulation misc review |
Chemical Slide Rules
The first chemical slide rules are of interest here because they are, in effect, early periodic tables. But the are more than this, as they can be used for performing chemical calculations. Writing in Bull. Hist. Chem. 12 (1992) (and here), William D. Williams of Harding University writes:
"An article by George Bodner in the Winter 1990 issue of the Bulletin described a rare chemical slide rule designed by Lewis C. Beck and Joseph Henry - their little-known Improved Scale of Chemical Equivalents. [My] paper attempts to place this slide rule in context by describing its origins, as well as some of its predecessors and successors."
Some chemical slide rules mentioned in the text:

- Chemist's Adjustable Duplex Slide Rule made by Keuffel & Esser Co., n.d., ca. 1936-1940. Here are the full instructions for use.
Nagayasu Nawa writes and provides an explanation as how Wollaston's chemical equivalents slide rules should be used:
"It is very interesting slide rule for me. Because we actually used slide rule in 1960s. There were not the electronic calculator in the world. I think it would be used as a simple slide rule of The Law of Definite Proportions by J.L. Proust 1799."
- '10 water', for example, may be hydrating water in chemical compound
- 'Chlorine' may be HClO: HCl(35) + O(10) = HClO(45), etc.
Click image to enlarge:
Thanks to Nawa for the tip!
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| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
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