CHAPTER 9 MIXTURES
9.4 LIQUID ANDSOLIDMIXTURES OFNONELECTROLYTES 250
BIOGRAPHICAL SKETCH
William Henry (1774–1836)William Henry was a British chemist, trained
as a physician, who is best known for his for-
mulation of what is now called Henry’s law.
Henry was born in Manchester, England.
His father was an apothecary and industrial
chemist who established a profitable business
manufacturing such products as magnesium
carbonate (used as an antacid) and carbonated
water. At the age of ten, Henry was severely
injured by a falling beam and was plagued by
pain and ill health for the rest of his life.
Henry began medical studies at the Univer-
sity of Edinburgh in 1795. He interrupted these
studies to do chemical research, to assist his
father in general medical practice, and to help
run the family chemical business. He finally
received his diploma of Doctor in Medicine in- In 1809, in recognition of his research
papers, he was elected a Fellow of the Royal
Society.
In 1801 the first edition of his influential
chemistry textbook appeared, originally called
An Epitome of Chemistryand in later editions
Elements of Experimental Chemistry. The
book went through eleven editions over a pe-
riod of 28 years.
Henry investigated the relation between the
pressure of a gas and the volume of the gas,
measured at that pressure, that was absorbed
into a given volume of water. He used a simple
apparatus in which the water and gas were con-
fined over mercury in a graduated glass vessel,
and the contents agitated to allow a portion of
the gas to dissolve in the water. His findings
were presented to the Royal Society of London
in 1802 and published the following year:a
The results of a series of at least fifty experi-
ments, on carbonic acid, sulphuretted hydrogen
gas, nitrous oxide, oxygenous and azotic gases,b
with the above apparatus, establish the follow-
ing general law:that, under equal circumstances
of temperature, water takes up, in all cases, the
same volume of condensed gas as of gas un-
der ordinary pressure. But, as the spaces oc-
cupied by every gas are inversely as the com-
pressing force, it follows,that water takes up, of
gas condensed by one, two, or more additional
atmospheres, a quantity which, ordinarily com-
pressed, would be equal to twice, thrice, &c. the
volume absorbed under the common pressure of
the atmosphere.
Henry later confirmed a suggestion made by
his close friend John Dalton, that the amount
of a constituent of a gaseous mixture that is ab-
sorbed is proportional to itspartialpressure.c
Henry carried out other important work,
chiefly on gases, including the elemental com-
positions of hydrogen chloride, ammonia, and
methane.
Because of his poor health and unsuccess-
ful surgery on his hands, Henry was unable to
continue working in the lab after 1824. Twelve
years later, suffering from pain and depression,
he committed suicide.
In a biography published the year after
Henry’s death, his son William Charles Henry
wrote:d
In the general intercourse of society, Dr. Henry
was distinguished by a polished courtesy, by an
intuitive propriety, and by a considerate fore-
thought and respect for the feelings and opinions
of others... His comprehensive range of thought
and knowledge, his proneness to general spec-
ulation in contradistinction to detail, his ready
command of the refinements of language and the
liveliness of his feelings and imagination ren-
dered him a most instructive and engaging com-
panion.
aRef. [ 75 ]. bThese gases are respectively CO 2 , H 2 S, N 2 O, O 2 , and N 2. cRef. [ 76 ]. dQuoted in Ref.
[ 156 ].