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On the Absorption of Gases by Water and other Liquids Dalton "brought about as profound a change in the nature of physical science as any one man has ever done." –Dictionary of National BiographySCARCE FIRST EDITION IN ORIGINAL BOARDS OF THE FIRST APPEARANCE OF DALTON'S ATOMIC THEORY OF MATTER, including the FIRST TABLE OF ATOMIC WEIGHTS and DALTON'S LAW OF PARTIAL PRESSURES. "It remains uncertain how Dalton arrived at the idea which was to change the philosophy of chemistry: he may have been led to it by reflection on such problems as the difference between the composition of a mixture of oxygen and nitrogen and a compound of oxygen and nitrogen; he must also have been familiar with the results of other investigators' work on the quantitative composition of many other compounds; and it is possible that he was led to it by seeking purely mechanical explanations of the behaviour of gases. The results he produced went beyond all this. The destruction of so much of his remaining papers in an air raid of 1940 may well make it impossible ever to arrive at an entirely satisfactory explanation of his mental processes. Be that as it may, he decided to make a remarkable addition to his paper of 21 October 1803 when it was in proof [published in 1805]: 'An enquiry into the relative weights of the ultimate particles in bodies is a subject , as far as I know, entirely new; I have lately been prosecuting this enquiry with remarkable success. The principle cannot be entered upon in this paper; but I shall just subjoin the results, as far as they appear to be ascertained by my experiments'" (Dictionary of National Biography). "Using simple assumptions and arguments, Dalton arrived at the first-ever list of relative atomic weights... No one took much notice at first, but gradually it dawned on the scientific community that Dalton's data opened the door to the experimental determination of the composition of molecules, in term of atoms. The first step in determining the nature of any molecule is to find out which types of atoms it contains and how many there are of each type. Without relative atomic weights this was impossible. Lavoisier had not believed in atoms; Dalton did. After Dalton, it was accepted by almost all scientists that atoms existed, that they had fixed weights, and that they were indivisible" (Brian L. Silver, The Ascent of Science). Law of partial pressures: Although first hinted at in a paper published in Nicholson's Journal in 1801, Dalton's law of partial pressures was first developed and explained in "On the Absorption of Gases." Dalton "held that each gas in a mixture of two gases behaves as if the other were not there: that the pressure of a gas mixture is made up of the sum of the partial pressures of the components. His view was challenged and controverted but it could not be ignored" (DNB). Dalton's law, as it is now known, is one of the staples of modern chemistry. This volume of the Memoirs contains three other papers by Dalton, “Experimental Enquiry into the Proportion of the several Gases or Elastic Fluids constituting the Atmosphere” (pp. 244-58), “On the Tendency of Elastic Fluids to Diffusion through each other” (pp. 259-73) and “Remarks on Mr. Gough’s two Essays on the Doctrine of Mixed Gases – In a Letter from the Author to Dr. Holme” (pp. 405-25), the latter referring to two papers by Gough also contained in this volume. The first of these papers by Dalton, which was read in November 1802, contains an anticipation of his law of multiple proportions in the statement “… the elements of oxygen may combine with a certain portion of nitrous gas or with twice that portion, but with no intermediate quantity” (p. 250).
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