In his researches, Roscoe showed that the atomic weight of the metal as determined by Berzelius and the formulae given to the oxides were incorrect, and pointed out that the element falls into its natural place in group V of the periodic classification along with phosphorus and arsenic, and not in the chromium group where it had originally been placed.
Del Rio; subsequent elaborate researches by Sir Henry Roscoe showed many inaccuracies in the conclusions of earlier workers (for instance, the substance considered to be the pure element was in reality an oxide) and provided science with an admirable account of this element and its compounds.
On the 18th of January 1881 he was elected United States senator, but resigned, with his colleague, Roscoe Conkling, on the 16th of May following, chiefly because President Garfield, in spite of their protest, had appointed as collector of the port of New York, Judge William H.
See Henry, Life of Dalton, Cavendish Society (1854); Angus Smith, Memoir of John Dalton and History of the Atomic Theory (1856), which on pp. 253-263 gives a list of Dalton's publications; and Roscoe and Harden, A New View of the Origin of Dalton's Atomic Theory (1896); also Atom.
His cause was espoused by Senator Roscoe Conkling, for a time successfully; but on the 11th of July 1878, during a recess of the Senate, the collector was removed, and in January 1879, after another severe struggle, this action received the approval of the Senate.
But from a study of Dalton's own MS. laboratory notebooks, discovered in the rooms of the Manchester society, Roscoe and Harden (A New View of the Origin of Dalton's Atomic Theor y, 1896) conclude that so far from Dalton being led to the idea that chemical combination consists in the approximation of atoms of definite and characteristic weight by his search for an explanation of the law of combination in multiple proportions, the idea of atomic structure arose in his mind as a purely physical conception, forced upon him by study of the physical properties of the atmosphere and other gases.
Sharpe, the surveyor of the customs. While these measures were of limited scope and effect, they served greatly to facilitate the more extensive reform of the civil service which subsequently took place, though at the same time they alienated a powerful faction of the Republican party in New York under the leadership of Roscoe Conkling.