Wednesday, December 15, 2010

Taking Measure

One thing that has been on my mind for a little while now is how can we best handle the subject of weights and measurements.  For example, it's possible to translate from a dead language to one that's in use, as was discussed earlier.  Measurements, however, need to have a literal, physical aspect to them that can't be conveyed in the written word.  For example, I can say that a foot is equal to an average man's foot in length.  Okay, great, what average man?  Obviously, it could be a little more closely approximated by taking a set of thirty men (for you stats buffs) and measuring their feet, but it would still only be approximate.

This leaves a few possibilities for handling the issue.  The first is to simply suggest that everyone have pound and kilogram measures and a foot/centimeter ruler stuck in their Repository someplace and forget about it (clearly, it would be important to store good quality weights and measures).  I haven't checked, but I think that it's reasonable that there are probably surplus weights available now that digital scales have become the norm. 

The second possibility is to determine a set of objects which are reasonably consistent in their weights and dimensions and use these as suggested "standards" which to go by.  For example, a quarter is around an inch in diameter.  Obviously, the big problem with this approach is the question of availability of the alternative standard for measurement.

Last is the notion that new standards of measurement may simply develop over time as civilization bottoms out and people begin to rebuild.  While this is the simplest solution, it would make translation of technical documents more difficult, if not impossible.  Whether or not this really matters is still up in the air, though I think it's likely that some form of industry will exist down the road, even if it's not nearly as ubiquitous as it is now. 

One other point I wanted to cover was the issue of metric vs. US customary measurements.  People feel strongly about both, and, having dealt extensively with both, I think both have their merits.  Metric is very good for scientific and technical measurements, but not nearly as representative of the real world as US customary is in dealing with real world measures.  For example, the end segment of the thumb is around an inch.  A man's foot is around a foot.  At the same time, trying to do math with inches, pounds or ounces is a pain in the neck, so for technical applications, metric has the lead with its decimal-based math.

Finally, the last consideration is that of the need to translate measurements when two different systems are in use.  Preferably, a trusted party would be available to calibrate scales and perform measurements if parties from different regions were attempting to engage in trade with each other, something that may become an issue as localized communites once again reach out to trade with each other.


  1. See the book "Uriel's Machine" for how to calculate a standard measure of length -- the "neolithic yard" -- across all cultures and times. Basically, a neolithic yard is the length of pendulum needed such that the pendulum swings 366 times during the transit of a star. Other such ancient Earth-based measurement units exist in a coherent whole that modern culture has not only forgotten but has actively tried to obliterate.

  2. Water is the key to connecting distance and mass (or weight, if you prefer). A US Pint weighs one pound. If you have a pint jar, you can calibrate a scale. There are 16 ounces in a pound, so you can derive a standard ounce by dividing a pound in half four times. Dividing by half requires just a balance; dividing a kilogram by ten is not so easy. In SI units (the scientific metric system), a cubic centimeter of water weighs one gram, so a carefully-constructed water-tight box can approximate an arbitrary weight.
    Of course, a box of water doesn't have the precision of a cylinder of exotic alloys, but I think we're worried more about weighing carrots than karats here.

  3. Thanks to both of you for the suggestions. This has been one of the problems which I've seen as being an important "keystone" problem for the Society. Boorstin proposed that the establishment of a reliable system of time made the Renaissance and Enlightenment possible, but I think also a consistent system of measurements of weight and volume is also necessary to rebuilding in a future age.

  4. 10 cm is the approximate breadth of a man's hand. 1 cm is the approximate breadth of a finger. 1 kg is the weight (or to be picky) the mass of one liter (10 cm cubed) of water. One degree celsius is 1/100 of the temperature difference between the boiling and freezing points of plain water (not brine of a specific degree of saltiness, which is what Gabriel Fahrenheit's scale was based on).

    All the metric measurements also have easy approximate human analogues and are also based on a numeral system that is based on the number of fingers a typical human has.