Perhaps we will also have to agree to disagree. However, I will try once more. I believe you are looking at it as though the calorie was only used to describe the energy content of food. Perhaps Lulu had more of a role in that than I give her credit for. However, the real, compelling reason to understand heat and to use water as a "standard fluid" to measure it is amazingly simple: steam and steam tables. Until the invention and perfection of the internal combustion engine, steam powered the Industrial Revolution. Understanding the heating of water, first to boiling then to steam was of vital importance to engineers of the 19th century. Cold water is cheap; steam is dear. Whether heat was some magic "caloric" or just thermal energy was not as important as practical results applicable to making steam. I will contend a great deal of effort was put into those results for very practical reasons and they had a reasonable experimental understanding. BTW, my 1962 Handbook of Chemistry & Physics has steam tables laid out with Imperial and metric side by side using Calories/kilogram and BTU per pound, for the liquid, heat of vaporization, and the vapor. The modern concept of course would be total enthopy in joules per kilogram. In the modern sense, we make much of the minor differences in the calorie at various temperatures (obviously knowing whether a gram-calorie or kilogram calorie is important), However, the total dispersion of the various recognized calories is about ±0.1%. Retail weighing accuracy in the range 0.1 to 0.5% is usually considered acceptable, so this is good enough for trade, if not satisfying to metrologists. I would liken the notion of caloric to the notion of electromagnetic waves travelling through ether (aether?). It was a faulty notion, but it did not stop progress from being made. However, the rate of progress improved when it fell by the wayside. My main point is that the calorie was NOT invented for food nutrition (or by Lulu) but primarily to better understand the properties and economics of steam, a matter of some importance in the 19th century (and today). I think it was a better developed concept that you acknowledge. It was eminently practical and germane even if the theoretical underpinnings were a bit flawed.
--- On Mon, 7/20/09, Pat Naughtin <[email protected]> wrote: From: Pat Naughtin <[email protected]> Subject: [USMA:45436] Re: Names of old measuring methods To: "U.S. Metric Association" <[email protected]> Date: Monday, July 20, 2009, 7:50 PM 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.
