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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.

Use the drop menus below to search & select from the more than 1300 Period Tables in the database: 

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Year:  1813 PT id = 1043

Wollaston's Slide Rule of Chemical Equivalents

Philosophical Transactions: A Synoptic Scale of Chemical Equivalents by William Hyde Wollaston, M.D. Sec. R.S. – or from here – has a diagram for a slide rule of chemical equivalents:

Wollaston writes:

"In order to shew more clearly the use of this scale, the Plate [diagram of the chemical slide rule] exhibits two different situations of the slider, in one of which oxygen is 10 [oxygen is defined as having an atomic weight/mass of 10.00], and other bodies are in their due proportion to it, so that carbonic acid being 27,54, and lime 35,46, carbonate of lime is placed at 63.

"In the second figure, the slider is represented drawn upwards till 100 corresponds to muriate of soda [sodium chloride, NaCl]; and accordingly the scale then shews how much of each substance contained in the table is equivalent to 100 of common salt. It shews, with regard to the different views of the analysis of this salt, that it contains 46,6 dry muriatic acid [hydrogen chloride], and 53,4 of soda, or 39,8 sodium, and 13,6 oxygen; or if viewed as chlorid of sodium, that it contains 60,2 chlorine, and 39,8 sodium."

Read more in an entry concerning chemical slide rules.

Thanks to Nawa for the tip!

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What is the Periodic Table Showing? Periodicity

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