7 The 100 Most Influential Inventors of All Time 7by Pappus of Alexandria (fl. 300 CE), as is also the
Baroulcus (“Methods of Lifting Heavy Weights”). Mechanica,
which is closely based on the work of Archimedes, pres-
ents a wide range of engineering principles, including a
theory of motion, a theory of the balance, methods of
lifting and transporting heavy objects with mechanical
devices, and how to calculate the centre of gravity for
various simple shapes. Both Belopoeica and Mechanica
contain Heron’s solution of the problem of two mean
proportionals—two quantities, x and y, that satisfy the
ratios a:x = x:y = y:b, in which a and b are known—which
can be used to solve the problem of constructing a cube
with double the volume of a given cube.
Only fragments of other treatises by Heron remain.
One on water clocks is referred to by Pappus and the phi-
losopher Proclus (410–485 CE). Another, a commentary on
Euclid’s Elements, is often quoted in a surviving Arabic work
by Abu’l-‘Abbās al-Fadl ibn Hātim al-Nayrīzī (c. 865– 922).
Johannes Gutenberg
(b. 14th century, Mainz [now in Ger.]—d. probably Feb. 3, 1468, Mainz)
J
ohann Gensfleisch zur Laden zum Gutenberg was a
German craftsman and inventor who originated a method
of printing from movable type that was used without
important change until the 20th century. The unique
elements of his invention consisted of a mold, with punch-
stamped matrices (metal prisms used to mold the face of
the type) with which type could be cast precisely and in
large quantities; a type-metal alloy; a new press, derived
from those used in wine making, papermaking, and book-
binding; and an oil-based printing ink. None of these
features existed in Chinese or Korean printing, or in
the existing European technique of stamping letters on
various surfaces, or in woodblock printing.