John Hall Gladstone was a British chemist. He was also Fullerian professor of chemistry at the Royal Institution.
Background
John Gladstone was born on March 7, 1827, in London, United Kingdom. His father, John Gladstone, a junior partner in the firm of Cook and Gladstone, wholesale drapers, married a cousin, Alison Hall, whose father also owned a drapery business. John Hall was the eldest of their three sons.
Education
John was educated at home under tutors and showed an early interest in natural science. At seventeen Gladstone wished to enter the Christian ministry but was dissuaded and entered University College, London. In 1848 he received a Ph.D. from the University of Giessen.
John returned to London in 1848 and in 1850 became a lecturer in chemistry at St. Thomas’ Hospital, where he stayed for two years. From 1874 to 1877 he was Fullerian professor of chemistry at the Royal Institution.
In a paper of 1853, Gladstone arranged all the known elements in the order of their “atomic weights,” thus anticipating John Newlands and others in pointing out certain peculiarities and drawing attention to some surprising relationships existing between the atomic weights of related elements, including some relationships observed earlier by Johann Döbereiner.
In 1855 he carried out the first quantitative investigation of equilibria in homogeneous systems, particularly using solutions of various ferric salts and thiocyanates, choosing these reactions because of the red color of the ferric thiocyanate thus formed. Since the reaction never went to completion in any one direction, the inadequacy of prevailing ideas on chemical affinity was demonstrated.
Gladstone’s important pioneering work on refractivity, in collaboration with T. P. Dale, began in 1858 with the measurement of the decrease in the refractive indexes of a number of liquids with an increase in temperature. Observations of this in connection with accompanying changes of density subsequently led them to the formulation of what they called the specific refractive energy, which they found to be approximately constant for a given liquid. Hans Landolt termed the product of this and the atomic weight of an element the refraction equivalent, and Gladstone subsequently measured it for a number of elements, finding it to be additive in compounds.
In a series of researches with Alfred Tribe, the copper-zinc couple was introduced and used in a number of organic preparations. His work on essential oils in his refractivity experiments led Gladstone to analyze them, and he discovered a number of terpenes.