Prout's hypothesisn.
/ˈpraʊts hʌɪˌpɒθᵻsɪs/, U.S. /ˈpraʊts (h)aɪˈpɑθəsəs/ Chemistry. Now historical.
The hypothesis that the atomic weights of chemical elements are integral multiples of the atomic weight of hydrogen.The hypothesis, which Prout and others interpreted to mean that atoms of heavier elements were built up of atoms of hydrogen (or that they might all be made from common building blocks), is not verified by measurement, although it is approximately correct in many cases.
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the world > matter > chemistry > atomic chemistry > [noun] > atoms > atomic weight or mass
atomic weight1819
Prout's hypothesis1860
atomic mass1884
1825 T. Thomson Attempt to Establish First Princ. Chem. I. vi. 160 The law of Dr. Prout, which will be found to hold in the atomic weights of all bodies, shows us that this number is a very little too high.
1833 Philos. Trans. (Royal Soc.) 123 544 Under such circumstances, Dr. Prout's hypothesis, as advocated by Dr. Thomson,—that all atomic weights are simple multiples of that of hydrogen,—can no longer be maintained.]
1860 W. A. Miller Elements Chem. (ed. 2) I. xix. 862 The verification or disproof of Prout's hypothesis acquires a high interest from its connexion with the nature of the elementary bodies themselves.
1940 G. H. J. Adlam & L. S. Price Higher School Certificate Inorg. Chem. (ed. 2) lvi. 586 Prout's hypothesis was revived from time to time and stimulated much accurate work in atomic weight determination.
1989 C. Howson & P. Urbach Sci. Reasoning: Bayesian Approach iv. 97 The atomic weights recorded at the time, though close to being integers when expressed as multiples of the atomic weight of hydrogen, did not match Prout's hypothesis exactly.
This is a new entry (OED Third Edition, September 2007; most recently modified version published online March 2022).
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n.1860