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Jim Green wrote:_______________________________________________
A little tutoring if you will:
Who invented the idea of caloric?
What was the motivation?
TX
Jim
Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen
The caloric model seems to have been invented by William Cleghorn, who
died at an early age. There is a popular, but informative, account of
this at http://www.uh.edu/engines/epi1956.htm
<http://www.uh.edu/engines/epi1956.htm>
as noted below. Joseph Black seems to have taken over the idea with some
reservation. However, neither Cleghorn or Black used the name "caloric,"
which seems to have been introduced by Antoine Lavoisier. As Hugh
Haskell pointed out, Count Rumford (Benjamin Thompson) called the
caloric model into question, because, if I remember correctly, the
generation of heat
during the cannon boring process depended on the amount of work done.
The idea of an limitless amount of heat contradicted the idea of a
finite amount of fluid. However, as Brian indicated, the caloric idea
persisted into the nineteenth century. I recall that Cleghorn was
influenced by other fluid models popular at the time -- including
Benjamin Franklin's single fluid model of
electricity.
The idea of caloric came up in April on PHYSHARE, when someone asked
about the history of specific heats and the motivation for their
introduction. Joseph Black is credited with the concepts of specific
heat capacity and "latent" heats of vaporization and fusion. I couldn't
find out much about practical applications of specific heat that
motivated Joseph Black
to introduce them. However, Joseph Black helped James Watt in the
development of the steam engine with his concept of heat of
vaporization. He apparently discussed specific and "latent" heats in
terms of what amounted to the caloric model. As indicated below, he only
referred to Cleghorn's model of heat as the most probable explanation,
not completely endorsing it.
The most scholarly reference on these matters seems to be _The Discovery
of Specific and Latent Heats_ by McKie and Heathcote referred to below.
I recall seeing a paper by Thomas Kuhn in which he referred to the
brilliant discussion in this book. The philosophical reference,
<http://philsci-archive.pitt.edu/archive/00001098/00/Stanford.doc> noted
below lists this book and several others about the caloric concept -- at
the end of the article.
I am about to go out of town again, so I won't be able to participate
much more in this discussion. The two postings that I placed on PHYSHARE
in April are copied below, the more recent (and more relevant), first:
Hugh Logan wrote:
Searching the web, I found that the concepts of specific heat and
"latent heat"
seem to have been introduced by Joseph Black (1728-1799). There is some
brief
biographical material at <http://www.answers.com/Joseph%20Black>. A book
According to
Taylor (p. 265), Black was the first to make a clear distinction between
heat and temperature. He was apparently the author of the caloric
theory, although others coined the word "caloric."
According to Lloyd W. Taylor's book, _Physics, the Pioneer Science_, pp.
266-267, "Some time during the latter part of his [Black's] life the
name _caloric_ was coined to denominate the 'matter of heat,' and
Black's views on the nature of heat have accordingly come to be known as
the 'caloric' theory. Black himself never used the term, however." This
seems to be a somewhat simplified account of the history.
It appears that the real originator of the caloric theory was William
Cleghorn (1751-1783?). There is a very accessible biographical sketch of
Cleghorn and his relation to Joseph Black's work at
http://www.uh.edu/engines/epi1956.htm, although I couldn't get the audio
file to play. On this web page (and others) it is mentioned that Antoine
Lavoisier was the person that actually coined the word "caloric,"
consistent with what Taylor wrote. However, some have questioned whether
or not Joseph Black completely accepted the caloric theory that he
learned of from Cleghorn. He considered it the most probable theory that
he knew of, but did not completely endorse it. Black was a staunch
Scottish empiricist and Newtonian inductivist not inclined to
theorizing.
<http://philsci-archive.pitt.edu/archive/00001098/00/Stanford.doc> (p.
14 of PDF file). This philosophical
paper referred to the book by McKie and Heathcote that Taylor used as a
source. It is apparently very scarce and expensive, but it might be
available in large university libraries.
Hugh Logan
Retired physics teacher
Searching the web, I found that the concepts of specific heat and
"latent heat"
seem to have been introduced by Joseph Black (1728-1799). There is some
brief
biographical material at <http://www.answers.com/Joseph%20Black>. A book
that might
be helpful is _Physics, The Pioneer Science, Vol.1 Mechanics, Heat, and
Sound_ by
Lloyd W. Taylor. It was originally published by Houghton Mifflin Company
in 1941, and
there is a Dover printing from 1959. Unfortunately, both are out of
print, but
copies are available at abebooks.com. This book is an elementary
treatment of physics
in a historical context with many historical references. According to
Taylor (p. 265), Black was the first to make a clear distinction between
heat and temperature. He was apparently the author of the caloric
theory, although others coined the word "caloric." Black called it
"matter of heat" or "quantity of heat."
Similarly, although he introduced the concept of specific heat, he used
the expression "capacity for heat."
(I recall using "heat capacity" for a given sample, with "specific heat
capacity" being the heat capacity per unit mass.) Apparently, there were
serious misconceptions about the distinction between heat and
temperature well into the eighteenth century, even in the best books on
chemistry. Taylor cites _Elementa Chemiae_ by Hermann Boerhaave, 1732
(English translation 1741). At that time, an equal-heat-content theory
prevailed. According to Boerhave, if a number of bodies were in thermal
equilibrium, equal volumes contained the same amount of heat, no matter
what the bodies were composed of. Others thought that the heat
distributed according to the weight rather than the volume. Black spoke
out against these views.
Black apparently interpreted the results performed much earlier by
Fahrenheit in which water and mercury
and water at different temperatures were mixed. The difference in the
specific heats of water and mercury was clearly explained by Joseph
Black. Taylor quotes Black's explanation. In discussing Black's work,
Taylor draws heavily from _A Source Book in Physics_ by W. F. Magie, New
York: McGraw-Hill, 1935. I remember this book, but I haven't seen it for
years. Taylor also refers to _The Discovery of Specific and Latent
Heats_ by D. McKie and N. H. de V. Heathcote, London: Edward Arnold &
Co., 1935, which has a description of Black's method of determining
specific heats (added by an editor of Black's _Lectures_.)
The exact date for Joseph Black's introduction of "capacity of heat" is
not known exactly, because the data was obtained from student notes
after Black's death. It was some time in the middle of the eighteenth
century. Although thermometers were developed in the seventeenth
century, misconceptions about the nature of heat apparently delayed the
introduction of specific heat. I gather that the calorie was not
introduced until the concept of "quantity of heat" was established.
Apparently, Black used the Fahrenheit temperature scale and English
units for other measurements (Taylor, p. 280). I do not know who
introduced the "calorie" as a unit, but it undoubtedly was not coined
until Black's "matter of heat" was called "caloric" by others --
probably in the latter part of the eighteenth century. Black did use
water for a comparison.
As for the importance of specific heats in a more advanced context, one
might look into the law of Dulong and Petit. Although simple, it is
related to ideas in atomic physics.
Hugh Logan
Retired physics teacher
Hugh Logan