TEST 21
READING
IELTS 5 Practice Tests, Academic Set 5
Page 132
READING PASSAGE 2
You should spend about 20 minutes on
Questions 14 - 26
, which are based on Reading Passage 2
below.
Sir Humphry Davy
Sir Humphry Davy was an English chemist. Born in Penzance in 1778, Davy attended a
local Grammar
School before returning to his home town as an apothecary’s apprentice. In 1798, he moved to Bristol
to work at Thomas Beddoes’s Pneumatic Institution where he discovered the physiological effects of
nitrous oxide while exploring the applications of various other gases.
After performing his experiments on nitrous oxide, he was later in 1798 named chemical
superintendent to the Institute of Science, a foundation in London that investigated the medical
benefits of various gases. He published his results in 1800, which earned him the
opportunity to start
lecturing at the new Royal Institution of Great Britain in the same year. His lectures were surprisingly
successful, even beyond narrow scientific circles, and enabled him to meet and befriend some of the
most important figures of the day.
Davy moved to London in 1801 to work at the Royal Institution as Assistant Lecturer. He proved to be
an extremely gifted lecturer and was promoted to Professor of Chemistry the following year. Davy was
famous for his lectures, which were so popular that a one-way system was put in place in Albemarle
Street to cope with the traffic, but he was also interested in pursuing chemical research in the Royal
Institution laboratories. Much of Davy’s important work in the first decade of the
nineteenth century
focused on the relationship between chemistry and electricity. Having concluded that electrolytic cells
generated electrical energy through a chemical process, he speculated that electrolysis might be used
to decompose substances into their elements. Although he overestimated the ability of electrolysis, he
did successfully isolate sodium and potassium, and was the first to discover boron, hydrogen telluride,
and hydrogen phosphide. He was later instrumental in identifying other elements such as chlorine and
iodine, which had been discovered, but were thought to be compounds.
In 1812, Davy was knighted and married a wealthy widow, Jane Apreece,
who gave him a son, Jack, in
the same year. He then retired from lecturing, although not from research. His last important act at the
Royal Institution, of which he remained honorary professor, was to interview the young Michael
Faraday, later to become one of England’s great scientists, who became laboratory assistant there in
1813 and accompanied Davy on a European tour. Davy’s fame was such that he was granted special
permission to travel to the continent to meet with other famous scientists. However, the political
situation was fragile and the trip had to be cut short in 1815 on Napoleon’s escape from Elba. With the
aid of a small portable laboratory and of various institutions in France and Italy, he conducted further
investigations on various compounds of iodine and chlorine. He also analysed many specimens of
classical pigments and proved that diamond is a form of carbon.
In 1819, by order of the Society for Preventing Accidents in Mines, Davy studied the conditions under
which mixtures of firedamp and air explode. This led to the invention of the
helmet lamp and to
subsequent researches on flame, for which he received the Rumford medals from the Royal Society.
IELTS 5 Practice Tests, Academic Set 5
TEST 21
READING
Page 133
After this, Davy examined various magnetic phenomena caused by electricity and electrochemical
methods and explored whether they, in combination with iron and zinc plates, could prevent saltwater
corrosion to the copper sheathing on ships. Though the protective principles were made clear,
considerable fouling still occurred, and the method’s failure greatly vexed him.
Davy’s health was by then failing rapidly. In 1827, he departed for Europe and, in the summer, was
forced to resign the presidency of the Royal Society. Having to forgo business and field sports, Davy
wrote a book on fishing (something he’d always enjoyed) in the same year that contained engravings
from his own drawings. After a last, short visit to England,
he returned to Italy, settling in Rome in
February 1829. Though partly paralysed from a stroke, he spent his last months writing a series of
dialogues, which were later released posthumously. While touring in 1829, Davy suffered a further
severe stroke and died in Geneva in 1829. Davy had wished to be buried where he died, but had also
wanted the burial deferred in case he was only comatose. However, the laws of Geneva did not allow
any delay and it was performed a few days later.
One of Davy’s creations that we are in contact nearly every day is the
light bulb, which he invented in
1801. He was experimenting with electricity around 1800 when he invented an electric battery. When
he later connected wires to his battery and a piece of carbon, the carbon glowed, producing light,
which is now called an electric arc. It was neither sufficiently bright nor long lasting enough to be of
practical use, but it did demonstrate the principle. By 1806, he was able to demonstrate a much more
powerful form of electric lighting to the Royal Society in London. This was soon developed into the
basic light bulb that we know today, which is a glass envelope containing a
combination of inert gases
at low pressure. The current enters through a contact at the bottom end, just below the screw cap.
Connecting wires come up through a glass fuse enclosure. From this, a filament comes up, surrounded
by support wires and the electric arc is derived from this.
