Dear John,
Thanks for these notes.
One of the problems with the history of the word, calorie, is that
during its existence it has had several changes of identity. In the
late 18th Century (around the time of Pierre and Marie Lavoisier)
caloric was though to be a physical substance somewhat like oxygen and
nitrogen. It wasn't until Clément began to measure the amount of
caloric in 1824, and Joule and others, showed the 'mechanical
equivalent of heat' in 1843, that the concept of caloric quietly
changed to the idea of a non-physical concept called energy and the
measurement of caloric quietly changed to being measured using the
calorie as if it was a clearly defined unit. It wasn't because of the
temperature issue and because of the slightly changing amount of water
in a kilogram.
I won't go through the notes you provided point by point, except to
say that they can be misleading depending on whether the initial
scientific writer had in mind the earlier concept of a substance
called caloric or of an abstract concept of energy, and specifically
heat energy in these examples. It is probably impossible to pinpoint
the exact date that caloric changed to heat energy.
It seems to me that some of the Wikipedia writers have retrofitted the
modern concepts of energy and its interchangeability from one energy
form to another on to earlier writers who had no idea of this concept.
As an example, I suspect that Clément was measuring the substance of
caloric using the calorie but he could not have any idea of the
mechanical equivalent of energy or of the concept of the 'Law of
conservation of energy' as this didn't arise in the minds of Joule and
Lord Kelvin until probably the 1860s.
Leaving all that aside, the calorie has not had a fixed and definite
definition supported by a fully international authority anywhere or at
any time of its existence. I can see no point in supporting its
existence as if it were a credible unit simply because one woman was a
successful publicist for this word in 1919.
However, let me not denigrate Lulu Hunt Peters' achievements too
lightly. There are many on this list who would quite happily emulate
her success – albeit using metric system units. Let me elaborate on
this, again:
In 1919, a single woman, Dr Lulu Hunt Peters introduced a new
measuring unit to the public of the USA. She did not have government
support, she did not have scientific support, she did not represent
any organisation of higher learning, she did not have any legal
precedence, but she did change the world of measuring food energy in
the USA, and subsequently in much of the rest of the world. I am
reminded of Margaret Mead's line:
"Never doubt that a small group of thoughtful committed citizens can
change the world. Indeed, it is the only thing that ever has." —
Margaret Mead
However in this case, it was not a small group who succeeded in
changing the thinking of the USA but eventually most of the world, but
it was a single woman who applied a misguided word, calorie, to a
whole nation and eventually to almost all of the world.
In my opinion the word was wrong, but the woman was effective.
Dr Lulu Hunt Peters is worthy of respect and of study because many
promoters of the metric system want to emulate what she has done and
to introduce measuring words to whole populations. I say, look to her
methods, and copy them!
Cheers,
Pat Naughtin
Author of the forthcoming book, Metrication Leaders Guide.
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that they
now save thousands each year when buying, processing, or selling for
their businesses. Pat provides services and resources for many
different trades, crafts, and professions for commercial, industrial
and government metrication leaders in Asia, Europe, and in the USA.
Pat's clients include the Australian Government, Google, NASA, NIST,
and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com
for more metrication information, contact Pat at [email protected]
or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter
to subscribe.
On 2009/07/19, at 9:03 PM, John M. Steele wrote:
Pat,
The calorie is FAR older than Lulu. She may or may not have been
the first to apply it to nutrition.
http://en.wikipedia.org/wiki/Calorie
Some snippets from this source:
"The calorie is a pre-SI metric unit of energy. The unit was first
defined by Professor Nicolas Clément in 1824 as a unit of heat. This
definition entered French and English dictionaries between 1841 and
1867.[1] In most fields its use is archaic, having been replaced by
the SI unit of energy, the joule. However, in many countries it
remains in common use as a unit of food energy. In the context of
nutrition, and especially food labelling, the terms calorie (or
Calorie) and kilocalorie are interchangeable. In either case the
unit is approximately equal to 4.2 kJ. . . . .
The original definition by Clément was based on the kilogram. Other
definitions based on the gram have since been made. We thus have the
two major variants: the kilogram calorie and the gram calorie. One
thousand gram calories equal one kilogram calorie.
In the context of food energy the term calorie generally refers to
the kilogram calorie. However, the term kilocalorie (kcal),
referring to one thousand gram calories, is also in widespread use
especially by professional nutritionists (when speaking in terms of
calories rather than joules). To avoid confusion, the prefix kilo-
is not used with the kilogram calorie.
Kilogram calorie
The kilogram calorie, large calorie, food calorie, Calorie (capital
C) or just calorie (lowercase c) is the amount of energy required to
raise the temperature of one kilogram of water by one degree Celsius."
It has always been defined as the energy to heat 1 g or 1 kg of
water by 1 °C. Unfortunately the starting and ending temperature
were not made part of the definition, and the heat capacity of water
is not constant. Certainly, in high school physics, I learned the
calorie for thermal energy, and an experiment called "the mechanical
equivalent of heat" related it to the joule. Lulu's calorie is
merely the nutritional or kilocalorie cast into familiar Imperial
terms; it has never been measured as she describes it.
It was not until 1948 that the CPGM deprecated the calorie (the
various calories?) in favor of the joule for thermal energy.
Nutritionists were slower to follow. This seems to be the official
in view of WHO:
http://www.fao.org/docrep/meeting/009/ae906e/ae906e17.htm
While discussions began in 1966 (or earlier?), the recommendation
appears to have been adopted (as gradual conversion) in 1969.
--- On Sat, 7/18/09, Pat Naughtin
<[email protected]> wrote:
From: Pat Naughtin <[email protected]>
Subject: [USMA:45428] Re: Names of old measuring methods
To: "U.S. Metric Association" <[email protected]>
Cc: "U.S. Metric Association" <[email protected]>
Date: Saturday, July 18, 2009, 10:55 PM
On 2009/07/18, at 10:22 AM, John M. Steele wrote:
I don't know who Lulu is, but in her defense, her calorie is closer
to a calorie than many calories are.
Dear John,
Here is a little background to Lulu Hunt-Peters in the context of
energy measurements. In this context it is interesting to note that
Dr Lulu Hunt-Peters has been highly successful at changing the world
of food measurement to her idiosyncratic and unscientific measuring
word at the same time as the entire world of metrology has clearly
failed to promote their point of view. Dr Hunt-Peters did not have
government support, she did not have the support of the scientific
community, nor did she did not have any legal precedence. Basically,
all she had was the ability to write for women's magazines, and with
that talent she changed the entire world of measuring the energy in
food.
Think about the competition between the internationally recognised
metric unit for food energy, kilojoule, and some of the other common
measuring words such as, calories, Calories, gram calories,
kilocalories, or kilogram calories. Dr Hunt-Peters succeeded while
the world of scientific metrology failed!
You can find an outline of Lulu Hunt Peters life at http://calorielab.com/news/2005/09/16/lulu-hunt-peters-and-the-birth-of-the-modern-diet-book/
and a copy of her main book from http://www.gutenberg.org/etext/15069
Here is a summary of the history of food energy.
There has been only one official metric unit for measuring food
energy since 1889 — kilojoules. For example, a slice of bread
contains about 250 kilojoules of food energy and a sweet biscuit has
about 500 kilojoules of food energy. The kilojoule had been accepted
as the sole unit for energy internationally since 1889.
However in 1918, 29 years after the establishment of the kilojoule
as an international standard unit for measuring the energy in food,
Dr Lulu Hunt Peters popularised an alternative word, 'calorie', to
describe food energy in the USA. However, she avoided defining the
concept of food energy by writing,
'… hereafter you are going to eat calories of food. Instead of
saying one slice of bread, or a piece of pie, you will say 100
calories of bread, 350 calories of pie.'
Food energy and measuring have been profoundly muddled ever since
the publication of the book, Diet and Health in 1918.
As a child, Lulu Hunt Peters was aware of her problem with body mass
when she wrote, '… that there is genuine mental suffering in being
an obese child.' She knew this from her own experience as a child
and, as an adult, she reached a body mass of 100 kilograms when the
body mass of an average woman was close to 65 kg.
Dr Hunt Peters defined a calorie as the amount of heat needed to
heat 4 pounds of water by 1 degree Fahrenheit. She based her
definition on the German research into dog digestion done by W. O.
Atwater who was investigating the best way to use dog droppings for
tanning leather.
Many attempts were made later to define the word, calorie, in metric
terms. For example, the size of a calorie depends on the temperature
at which it is defined; technically on a scale of 32 to 212 degrees
Fahrenheit there are 180 possible definitions for the word, calorie.
But this only led to more confusion as different groups then devise
different definitions for the different ways that a calorie might be
spelled; one example is that a Calorie (with an upper case C) is
1000 times larger than a calorie (with a lower case c). This is why
we have: calories, Calories, gram calories, kilocalories, kilogram
calories, and perhaps 20 or 30 other spelling varieties with
potentially different values. Like other old pre-metric measures
there are now far too many different calories (or Calories or
kilocalories) that have many different names and varying values.
The existence of these seemingly good choices (kilojoule accurate,
the others popular) means that the debate between them will continue
for many generations, with nutritionists and dieticians dithering
between them. To a measurement specialist there is only one choice,
the kilojoule, but I suspect that women's and diet magazines will
continue dithering. You can only avoid dithering by adopting a
definite measurement policy for yourself or the group that you
represent.
When you write: 'her calorie is closer to a calorie than many
calories are' you are accepting the definition of one group, in one
place, who have defined the word calorie according to their own
requirements. To the best of my knowledge, no international
authority has been able to define a 'universal calorie. For example,
BIPM (at http://www1.bipm.org/en/si/si_brochure/chapter4/
table10.html ) simply notes that a number of different calories have
been used in the past, they write:
i) Several "calories" have been in use: a calorie labelled "at 15
°C": 1 cal15 = 4.1855 J (value adopted by the CIPM in 1950; PV,
1950, 22, 79-80); a calorie labelled "IT" (International Table): 1
calIT = 4.1868 J (5th International Conference on the Properties of
Steam, London, 1956); a calorie labelled "thermochemical": 1 calth =
4.184 J.
Cheers,
Pat Naughtin
Author of the forthcoming book, Metrication Leaders Guide.
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that
they now save thousands each year when buying, processing, or
selling for their businesses. Pat provides services and resources
for many different trades, crafts, and professions for commercial,
industrial and government metrication leaders in Asia, Europe, and
in the USA. Pat's clients include the Australian Government, Google,
NASA, NIST, and the metric associations of Canada, the UK, and the
USA. See http://www.metricationmatters.com for more metrication
information, contact Pat at [email protected] or
to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter
to subscribe.
