John Perry (engineer)
Encyclopedia
John Perry was a pioneering engineer
and mathematician
from Ireland
. He was born on February 14, 1850 at Garvagh
, County Londonderry
, the second son of Samuel Perry and a Scottish-born wife.
Perry worked as Lord Kelvin
's assistant at the University of Glasgow
, and later became professor of mechanical engineering
at Finsbury Technical College. He was a colleague of William Edward Ayrton
and John Milne
at the Imperial College of Engineering
in Tokyo
, 1875–79, and was also a Fellow of the Royal Society. In 1900 he was elected president of the Institution of Electrical Engineers
. and from 1906-08 served as president of the Physical Society of London
.
inside the Earth, and thus disputing Kelvin's estimate that the Earth was only 20–400 million years old, but this had little impact. It was not until the discovery in 1903 that radioactive decay
releases heat and the development a few years later of radiometric dating
of rocks that it was accepted that the age of the earth was many times older, as Perry had argued. Perry's reasoning held that if the interior of the Earth was fluid, or partly fluid, it would transfer heat much more effectively than the conductivity which Kelvin assumed, and he stated that "much internal fluidity would practically mean infinite conductivity for our purpose."
Kelvin rejected this idea as there was no evidence of tidal deformation of the Earth's crust, and in response Perry made a reference to Kelvin's favourite demonstration of the slow deformation of shoemaker's wax to illustrate the supposed qualities of the presumed luminiferous aether
thought then to be necessary to transmit light through space. Perry wrote that "the real basis of your calculation is your assumption that the solid earth cannot alter its shape ... even in 1000 million years, under the action of forces constantly tending to alter its shape, and yet we see the gradual closing up of passages in a mine, and we know that wrinkling and faults and other changes of shape are always going on in the earth under the action of long-continued forces. I know that solid rock is not like cobbler’s wax, but 109 years is a long time, and the forces are great."
The failure of the scientific community
to accept a fluid interior to the Earth held back ideas in geology
until the concept was revived by proponents of continental drift
, and even in the 1960s geophysical
models were still being constructed on the basis that the Earth was solid.
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
and mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
from Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
. He was born on February 14, 1850 at Garvagh
Garvagh
Garvagh is a village in County Londonderry, Northern Ireland. It is on the banks of the Agivey River, south of Coleraine on the A29 route. In the 2001 Census it had a population of 1,288.-History:...
, County Londonderry
County Londonderry
The place name Derry is an anglicisation of the old Irish Daire meaning oak-grove or oak-wood. As with the city, its name is subject to the Derry/Londonderry name dispute, with the form Derry preferred by nationalists and Londonderry preferred by unionists...
, the second son of Samuel Perry and a Scottish-born wife.
Perry worked as Lord Kelvin
William Thomson, 1st Baron Kelvin
William Thomson, 1st Baron Kelvin OM, GCVO, PC, PRS, PRSE, was a mathematical physicist and engineer. At the University of Glasgow he did important work in the mathematical analysis of electricity and formulation of the first and second laws of thermodynamics, and did much to unify the emerging...
's assistant at the University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...
, and later became professor of mechanical engineering
Mechanical engineering
Mechanical engineering is a discipline of engineering that applies the principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the...
at Finsbury Technical College. He was a colleague of William Edward Ayrton
William Edward Ayrton
-See also:*Henry Dyer*John Milne*Anglo-Japanese relations...
and John Milne
John Milne
For other uses, see John Milne .John Milne was the British geologist and mining engineer who worked on a horizontal seismograph.-Biography:...
at the Imperial College of Engineering
Imperial College of Engineering
The Imperial College of Engineering was founded as a university at Tokyo in 1873, though its predecessor the existed from 1871. The name "Kobu Daigakko" dates from 1877. In modern-day parlance it would have been called an institute of technology....
in Tokyo
Tokyo
, ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...
, 1875–79, and was also a Fellow of the Royal Society. In 1900 he was elected president of the Institution of Electrical Engineers
Institution of Electrical Engineers
The Institution of Electrical Engineers was a British professional organisation of electronics, electrical, manufacturing, and Information Technology professionals, especially electrical engineers. The I.E.E...
. and from 1906-08 served as president of the Physical Society of London
Physical Society of London
The Physical Society of London, England, existed from 1874 to 1921. It was a scientific society and produced the Proceedings of the Physical Society of London...
.
Challenging Lord Kelvin
In 1895, Perry published a paper challenging Kelvin's assumption of low thermal conductivityThermal conductivity
In physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....
inside the Earth, and thus disputing Kelvin's estimate that the Earth was only 20–400 million years old, but this had little impact. It was not until the discovery in 1903 that radioactive decay
Radioactive decay
Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...
releases heat and the development a few years later of radiometric dating
Radiometric dating
Radiometric dating is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates...
of rocks that it was accepted that the age of the earth was many times older, as Perry had argued. Perry's reasoning held that if the interior of the Earth was fluid, or partly fluid, it would transfer heat much more effectively than the conductivity which Kelvin assumed, and he stated that "much internal fluidity would practically mean infinite conductivity for our purpose."
Kelvin rejected this idea as there was no evidence of tidal deformation of the Earth's crust, and in response Perry made a reference to Kelvin's favourite demonstration of the slow deformation of shoemaker's wax to illustrate the supposed qualities of the presumed luminiferous aether
Luminiferous aether
In the late 19th century, luminiferous aether or ether, meaning light-bearing aether, was the term used to describe a medium for the propagation of light....
thought then to be necessary to transmit light through space. Perry wrote that "the real basis of your calculation is your assumption that the solid earth cannot alter its shape ... even in 1000 million years, under the action of forces constantly tending to alter its shape, and yet we see the gradual closing up of passages in a mine, and we know that wrinkling and faults and other changes of shape are always going on in the earth under the action of long-continued forces. I know that solid rock is not like cobbler’s wax, but 109 years is a long time, and the forces are great."
The failure of the scientific community
Scientific community
The scientific community consists of the total body of scientists, its relationships and interactions. It is normally divided into "sub-communities" each working on a particular field within science. Objectivity is expected to be achieved by the scientific method...
to accept a fluid interior to the Earth held back ideas in geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
until the concept was revived by proponents of continental drift
Continental drift
Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912...
, and even in the 1960s geophysical
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
models were still being constructed on the basis that the Earth was solid.