Atomic theory, historical

Alan J. Rocke, Atoms and Equivalents The Early Development of the Chemical Atomic Theory, Historical Studies in the Physical Sciences 9, 1978, 225-263 idem. Chemical Atomism in the Nineteenth Century (Ohio State University Press, 1984). 

N. Bohr, letter to D. Coster, July 3, 1922, in Collected Papers of Niels Bohr, edited by J. Rud Nielsen, vol. 4, North-HoUand Publishing Company, Amsterdam, 1981, as quoted in H. Kragh, Niels Bohr s Second Atomic Theory, Historical Studies in the Physical Sciences, 10, 123-186,1979. 

H. Kragh, Niels Bohr s Second Atomic Theory , Historical Studies in the Physical Sciences, 10(1979), I23-S5. 

Historically, the observation that volumes of reacting gases always simplified to ratios of small, whole numbers is called Gay-Lussac s Law of Combining Volumes. In the preceding example, the volumes of NO to 02 to N02 fit the pattern of 2 1 2. This observation further strengthened Dalton s argument for an atomic theory of matter. 

While the Epicurean model appeals to us as being closer to the modern view of atoms and is sometimes pointed to as the origin of atomic theory, in historical terms, it had little effect on the development of natural philosophy. The reason for this was twofold. First, the Epicureans were known less for their physical theories than for their ideas about social and personal behavior, favoring the pursuit of pleasure. Our modern use of the term epicure for someone who enjoys good food and drink reflects this. The second reason that... 

He was one of the earliest supporters of the doctrine of bodies combining in definite proportions, or of what is commonly called the atomic theory. Previous to introducing a paper of his in which this doctrine is happily illustrate by new and curious facts, I shall give a short historical sketch equally candid and perspicuous of the origin of this doctrine, and of its progress, vdiich forms a part of the Discourse he delivered as President of the Royal Society on the awardment of the first Royal medal to Mr. Dalton "for the developement of Ae chemical theory of definite proportions." -He proceeds, - "What Mr Daltons merits are, I shall briefly endeavor to state to you, though it is impossible to do justice to them in the time necessarily allotted to this address.""... 

Historically important in the development of modern atomic theory was the recognition that although polyatomic molecules show more or less broad bands of absorption and emission in the visible and ultraviolet regions of the spectrum, the characteristic light absorption or emission by individual atoms occurs at fairly narrow lines of the spectrum, which correspond to sharply defined wavelengths. The line spectrum of each element is so uniquely characteristic of that element that atomic spectroscopy can be used for precise elementary analysis of many types of chemically complex materials. 

Goodman, D. C. "Wollaston and the Atomic Theory of Dalton." Historical Studies in the Physical Sciences 1 (1969) 37-59. 

We begin with a historical perspective of the search for the fundamental units of matter. The modem version of atomic theory was laid hy John Dalton in the nineteenth century, who postulated that elements are composed of extremely small particles, called atoms. AH atoms of a given element are identical, but they are different from atoms of all other elements. (2.1)... 

Systematic presentation of the historic development of atomic theory helps students understand chemical thought and appreciate central ideas of the science. 

Historically, one of the key examples of this is the evaluation hy Einstein of the significance of Brownian motion, which led to the substantiation of the ideas behind the atomic theory of matter. Atomic theory was under challenge at the time from well-established and prestigious names within the scientific community. The phenomenon of Brownian motion and its interpretation was one major factor in the acceptance of the theory. Yet this acceptance involved interpretation of the unseen atomic world - the motion of sub-microscopic atoms and molecules - in terms of the motion of the seen world - the motion of smoke or dust particles under the microscope. 

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