MISCELLANEA. 
819 
least important paper, “ On Liquid Transpiration in relation to Chemical Composition,’ 
was communicated to the Royal Society in 1861. Of the three greater papers, that 
'• On Liquid-Diffusion applied to Analysis ” was communicated also in 1861. For this 
paper more especially, as well as for his Bakerian lectures “ On the Diffusion of 
Liquids ” and “ On Osmotic Force,” Mr. Graham received, in 1862, the Copley Medal 
of the Royal Society; and, in the same year, was also awarded the Jecker Prize of the 
Institute of France. Following in quick succession, his paper “ On the Molecular Mo¬ 
bility of Gases ” was presented to the Royal Society in 1863, and that ‘ k On the Absorp¬ 
tion and Dialytic Separation of Gases by Colloid Septa,” in 1866. With regard to 
these three great papers, two of them were each supplemented by a communication to 
the Chemical Society; while the third was supplemented by four successive notes to 
the Royal Society, containing an account of further discoveries on the same subject, 
hardly less remarkable than those recorded in the original paper. The last of these 
supplementary notes was communicated on June 10th, 1869, but a few months before 
the death, on September 13th, of the indefatigable but physically broken-down man. 
In considering Mr. Graham as a chemical philosopher and lawgiver we find him cha¬ 
racterized by a pertinacity of purpose peculiarly his own. Wanting the more striking 
qualities b} 7, which his immediate predecessors, Davy, Dalton, and Faraday, were seve¬ 
rally distinguished, he displayed a positive zeal for tedious quantitative work, and a 
wonderful keen-sightedness in seizing the points which his innumerable determinations 
of various kinds, conducted almost incessantly for a period of forty years, successively 
unfolded. His work itself was essentially that of detail, original in conception, simple 
in execution, laborious by its quantity, and brilliant in the marvellous results to which 
it led. As regards its simplicity of execution, scarcely any investigator of recent times 
has been less a friend to the instrument-maker than Mr. Graham. While availing 
himself, with much advantage, of appliances devised by Bunsen, Poisseuille, Sprengel, 
and others, all the apparatus introduced by himself was of the simplest character, and 
for the most part of laboratory construction. 
Essentially inductive in his mode of thought, Mr. Graham developed his leading 
ideas, one after another, directly from experiment, scarcely, if at all, from the prevailing 
ideas of the time. As well observed by Dr. Angus Smith, “ he seemed to feel his way 
by his work.” His records of work are usually, in a manner almost characteristic, pre¬ 
ceded each by a statement of the interpretation or conclusion which he formed ; but the 
records themselves are expressed in the most unbiassed matter-of-fact language. Sin¬ 
gularly cautious in drawing his conclusions, he announces them from the first with 
boldness, making no attempt to convince, but leaving the reader to adopt them or not 
as he pleases. Accordingly, in giving an account of his various researches, Mr. Graham 
rarely, if ever, deals with argument; but he states succinctly the experiments lie has 
made, the conclusions he has himself drawn, and not unfrequently the almost daring 
speculations and generalizations on which he has ventured. Some of these speculations 
on the constitution of matter are reproduced in his own words further on. 
Mr. Graham was elected a Fellow of the Royal Society in 1837, Corresponding 
Member of the Institute of France in 1817, and Doctor of Civil Law of Oxford in 1855. 
MISCELLANEA. 
Action of Direct Sunlight upon Iodide of Potassium.— M. Loew.—A solu¬ 
tion of iodide of potassium is, even when kept in well-closed bottles, slowly decomposed 
by the action of daylight, and assumes a somewhat yellowish tinge, due to free iodine. 
The author filled a number of glass tubes for about from one-half to three-fourths of 
their capacity, with a solution of iodide of potassium, and, after having sealed these 
tubes, exposed them to direct sunlight. Another set of tubes were likewise filled with 
the same solution, but all air was expelled, and the tubes sealed during and after the so¬ 
lution had been boiling for a considerable time. These tubes were also exposed to the 
action of direct sunlight; after three and four months’ exposure, the tubes and contents 
were examined ; those wherein no air at all was left were found to be perfectly colour¬ 
less, no decomposition of the contents having taken place. As regards the other tubes, 
the’following results are noticed (1.) Under the influence of light, the oxygen of the 
