Charles Hutton, “An Account of the Calculations Made from the Survey and Measures Taken at Schehallien, in Order to Ascertain the Mean Density of the Earth”; Charles Hutton, “The Force of Fired Gun-Powder"; John Hunter, “Of the Heat, &c. of Animals and Vegetables”; John Playfair, “On the Arithmetic of Impossible Quantities"; and many others all in the Philosophical Transactions.

The following papers are all found in one volume (facsimile reprint) of the Philosophical Transactions, London (printed in New York by Krauss Reprint and Johnson Reprint corporations, 1963. Reprinted with permission of the Royal Society of London, the only authorized facsimile edition. Volume 68, 1778 1098pp, with numerous folding plates. Bound in a sturdy cloth. Ex-library with the usual markings: paper spine label at spine bottom, rubber stamps n text block faces, bookplate. The text is very clean and fresh. Uncommon to find these works as hardbound copies! **The density of the Earth—a Major Paper** Charles Hutton, “An Account of the Calculations Made from the Survey and Measures Taken at Schehallien, in Order to Ascertain the Mean Density of the Earth” pp 689-788 (which is a very long article for the PT). "Core Objective: To calculate the deflection of a plumb-line caused by the gravitational pull of the mountain Schiehallion, and use that measurement to weigh the Earth. Major Contribution: Hutton invented the system of contour lines to map the elevations of the mountain and calculate its total volume and mass. Final Result: Hutton calculated the mean density of the Earth to be roughly 4.5 g/cm³ (about 1.8 times the density of the mountain's quartzite), correctly deducing that the Earth's interior must contain a massive metallic core."--NIH site ("Charles Hutton and the ‘Dissensions’ of 1783–84: scientific networking and its failures.") Charles Hutton, “The Force of Fired Gun-Powder, and the Initial Velocities of Cannon Balls, Determined by Experiments; From Which is Also Deduced the Relation of the Initial Velocity to the Weight of the Shot and the Quantity of Powder” pp 50-85. An important paper on quantitative experimental ballistics. John Hunter, “Of the Heat, &c. of Animals and Vegetables” pp 7-49. Sir William Hamilton, “A Letter from Sir William Hamilton . Giving an Account of Certain Traces of Volcanos on the Banks of the Rhine” pp 1-6. **Imaginary Quantities** John Playfair, “On the Arithmetic of Impossible Quantities" pp318-343. **Vision and muscular coordination** Erasmus Darwin, “A New Case in Squinting" pp 86-96. And many others in this thousand-page volume.…