Encyclopædia Britannica Third Edition

It was developed during the encyclopedia's earliest period as a two-man operation initiated by Colin Macfarquhar and Andrew Bell, in Edinburgh, Scotland.

The 3rd edition began the tradition (continued to the present) of dedicating the Britannica to the reigning British monarch, then King George III; describing him as "the Father of Your People, and enlightened Patron of Arts, Sciences and Literature", Gleig wished ...that, by the Wisdom of Your Councils, and the Vigour of Your Fleets and Armies, Your MAJESTY may be enabled soon to restore Peace to Europe; that You may again have leisure to extend Your Royal Care to the Improvement of Arts, and the Advancement of Knowledge; that You May Reign long over a Free, Happy and a Loyal People...Like the second edition, the volumes were written over a long period, from volume 1 in 1788 to volume 18 in 1797.

The final page of each volume of the Encyclopædia Britannica contains "Directions" to the binder for the correct placement of the 500+ copperplates and maps.

Several noted authorities contributed to this edition, such as Dr. Thomas Thomson (brother of James) who introduced the first usage of chemical symbols in the 1801 supplement (see below), and John Robison, Secretary of the Royal Society of Edinburgh, who wrote on natural philosophy.

The 3rd edition is also famous for its bold article on "Motion", which regarded Isaac Newton's theory of gravitation as erroneous.

Instead, authors James Tytler and Gleig wrote that gravity is caused by the classical element of fire.

They seem to have been influenced by William Jones's Essay on the First Principles of Natural Philosophy (1762), which in turn was based on John Hutchinson's MA thesis, Moses' Principia, which was written in 1724 but rejected by the University of Oxford.

In it, Gleig states, "Aerology, Aerostation, Chemistry, Electricity, Gunnery, Hydrostatics, Mechanics, with most of the separate articles in the various branches of natural history, we have reason to believe were compiled by Mr. James Tytler, chemist; a man who, though his conduct has been marked by almost perpetual imprudence, possesses no common share of science and genius."

The list of authors goes on, "Mary Queen of Scots, Instinct, Love, Metaphysics, Miracle, Moral Philosophy, Oath, Passion, Plastic Nature, Polytheism, Prayer, Slavery, and Supper of the Lord were contributed by Gleig, editor of the last 6 volumes."

Maxwell Morrison; Mysteries, Mythology and Philology by David Doig; Navigation, Parallax, Pendulum, Projection, Ship Building, and Naval Tactics by Andrew Mackay; and John Robison is credited with Physics, Pneumatics, Precession, Projectiles, Pumps, Resistance of fluids, Roof, Rope making, Rotation, Seamanship, Signals, Sound, Specific Gravity, Statics, Steam, Steam Engine, Strength of materials, Telescope, Tide, and Water Works.

Tytler's earlier treatise on balloon flight, written in 1784, appeared in the 200-page appendix to the second edition, in Volume 10 under "Air".

Dobson, an Edinburgh native and master printer who learned his craft in that city while the first two editions were being produced there, relocated to America in 1783.

Much new information about oxygen, combustion, and disproof of the phlogiston theory had been discovered since Tytler's day, and are explained in the supplements.

John Robison of Edinburgh wrote new articles: Arch, Astronomy, Carpentry, Center, Dynamics, Electricity, Impulsion, Involution and Evolution of Curves, Machinery, Magnetism, Mechanics, Percussion, Piano-Forte, Position, Temperament, Thunder, Trumpet, and Watchwork.

Encyclopædia Britannica , Third edition, 1797. Photo includes 18-volume third edition of 1797 plus two-volume supplement dated 1803.
Illustration of William Herschel's Grand Telescope of 1789.
Thomas Thomson was recruited by Britannica in 1796 to amend the Chemistry article, which had been written, probably by Tytler, using archaic ideas and terminology. Before beginning to re-write the entire article for the supplement, he authored this chart, to be used as an appendix to the article in the 3rd edition, showing the new nomenclature that Lavoisier, et al. had introduced in 1787. [ 6 ]
Table of chemical symbols used in the third edition, is exactly reproduced from the Second edition of 1784.
The only color plate to appear in the third edition, is hand-colored. The blue represents the horizon, the green in the center is the city of Chester, England, and the red is the river Dee.