8IS NOTICE OF THE LIFE OF THE LATE PROFESSOR GRAHAM. 
of Chemistry,’ and based on the above paper, will long be regarded as a model of lucid 
scientific exposition. 
In 1841 the now flourishing Chemical Society of London was founded; and thougtx 
Mr. Graham had been, at that time, but four years in London, such was the estimation 
in which he was held by his brother chemists, that he was unanimously chosen as the 
first President of the Society. The year 1844 is noticeable in another way. Wollaston 
and Davy had been dead for some years. Faraday’s attention had been diverted from 
chemistry to those-other branches of experimental inquiry in which his highest dis¬ 
tinctions were achieved ; and, by the death of Dalton in this year, Mr. Graham was 
left as the acknowledged first of English chemists, as the not unworthy successor to the 
position of Black, Priestley, Cavendish, Wollaston, Davy, and Dalton. 
From the period of his appointment at University College, in 1837, Mr. Graham’s 
time was fully occupied in teaching, in writing, in advising on chemical manufactures, 
in investigating fiscal and other questions for the Government, and in the publication 
of various scientific memoirs, several of them possessing a high degree of interest; but 
it was not till 1846 that he produced a research of any considerable magnitude. In 
that year he presented to the Royal Society the first part of a paper “ On the Motion 
of Gases,” the second part of which he supplied in 1849. For this research Mr. 
Graham was awarded a second Royal Medal of the Society in 1850. The preliminary 
portion of the first part of the paper related to an experimental demonstration of the 
law of the effusion of gases, deduced from Toricelli’s theorem on the efflux of liquids,— 
a demonstration that was achieved by Mr. Graham with much ingenuity, and without 
his encountering any formidable difficulty. But the greater portion of the first part, 
and whole of the second part, of this most laborious paper, were devoted to an investi¬ 
gation of the velocities of transpiration of different gases through capillary tubes ; with 
a view to discover some general law by which their observed transpiration rates might 
be associated with one another. Again and again, with characteristic pertinacity, Mr. 
Graham returned to the investigation ; but although much valuable information of an 
entirely novel character was acquired,—information having an important bearing on his 
subsequent work, — the problem itself remained, and yet remains unsolved. Why, for 
example, under an equal pressure, oxygen gas should pass through a capillary tube at a 
slower rate than any other gas, is a matter that still awaits interpretation. 
Near the end of the same year, 1849, Mr. Graham communicated, also to the Royal 
Society, a second less laborious, but in the novelty and interest of its results more suc¬ 
cessful paper ‘'On the Diffusion of Liquids.” It was made the Bakerian lecture for 
1850; and was supplemented by further observations communicated to the Society in 
1850 and 1851. In his investigation of this subject, Mr. Graham applied to liquids the 
exact method of inquiry which he had applied to gases just twenty years before, in that 
earliest of his papers on the subject of gas-diffusion published in the ‘Quarterly Journal 
of Scienceand he succeeded in placing the subject of liquid-diffusion on about the 
same footing as that to which he had raised the subject of gas-diffusion prior to the 
discovery of his numerical law. 
In 1854 Mr. Graham communicated another paper to the Royal Society “ On Osmotic 
Force,” a subject intimately connected with that of his last previous communication. 
This paper was also made the Bakerian lecture for the year; but, altogether, the con¬ 
clusions arrived at were hardly in proportion to the very great labour expended on the 
inquiry. In the next year, 1855, just five-and-twenty years after his appointment at 
the Audersonian University, Mr. Graham was made Master of the Mint; and, as a con¬ 
sequence, resigned his Professorship at University College. During the next five years 
he published no original work. 
Thus, at the beginning of the year 1861, Mr. Graham, then fifty-six years of age, 
had produced, in addition to many less important communications, five principal me¬ 
moirs, three of them in the highest degree successful; the other two less successful in 
proportion to the expenditure of time and labour on them, but, nevertheless, of great 
originality and value. The most brilliant period, however, of his scientific career was 
to come. In the year 1861, and between then and his death in 1869, Mr. Graham 
communicated four elaborate papers to the Royal Society ; three of them far exceeding 
in novelty, interest, and philosophic power, anything that he had before produced ; and 
the other of them, relating to a certain physical effect of that hydration of compounds, 
from the consideration of which his attention could never wholly be withdrawn. This 
