Great Geologists | 67
science and mathematics. His father died unexpectedly in
1847 and so at the age of 21 he inherited the family fortune.
Sorby used the monies he had been left to create a scientific
laboratory at the home he shared with his mother. He was
devoted to his mother for the rest of her life, and she either
accompanied him on his travels or he never left her for more
than four days at a time. In return, she encouraged him in his
research.
During the early part of his career, the primary outlets for his
endeavours were the meetings and reports of the Sheffield
Literary and Philosophical Society. His first paper published
in the reports of this society was on agricultural chemistry in
several years previously), the technique had largely been used
to study the structure of bones and fossils and never used
systematically to study rocks and minerals. Thus Sorby founded
microscopic petrography by using thin-sections of rock ground
to a thousandth of an inch to study their composition and origin.
By 1849 Sorby was able to present the earliest results of
his petrographic research to his local Sheffield society and
in 1851 published his first paper on the subject, discussing
some sedimentary rocks from the Yorkshire coast, where he
distinguished quartz, chalcedony and calcite apart by use of
polarized light on a rotating stage. His early efforts were not
always well received by the scientific community at large. He
Thin-section of an Oligocene limestone from north-western Turkey
1846, but a year later geology had become his main scientific
focus. In 1847 he published on fluvial geomorphology in
the Sheffield region. In 1848 he chanced to have a meeting
during a train journey that was to alter profoundly the course
of his research. The person he met was William Williamson,
a physician and jeweller (and subsequently an expert in
stratigraphic paleontology, paleobotany and foraminifera), who
made thin-sections of petrified wood, teeth and bones. Sorby
soon learned the preparation technique at Williamson’s home
and immediately started preparation of thin-sections of ordinary
rocks. Although the microscopic study of thin-sections was
not new (William Nicol had introduced a polarizing microscope
later said “In those early days people laughed at me. They
quoted Saussure who said it was not a proper thing to examine
mountains with a microscope, and ridiculed my actions in every
way. Most luckily I took no notice of them”. These attitudes
were to change when Sorby tackled the problematic origin of
slaty cleavage in metamorphosed sediments that can cut across
primary sedimentary fabric. From the microscopic study of
slates, he was able to determine that the cleavage originates
from the reorientation of mica under anisotropic pressure as
the original sediment undergoes deep burial. This research
(published in 1853 and 1856) brought him to the attention of the
scientific establishment, and he was duly created a Fellow of the
Royal Society when only 31 years old.