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11/14/2002
Measurements
I was sitting here at my desk trying to decide on a subject for this
column when I noticed the plastic ruler on my desk. The ruler
contains the logo of the Chemical Heritage Foundation and its
objective - "making the known the achievements of chemical and
molecular sciences." Measurement is a key ingredient in the
achievements in virtually all of science, certainly in experimental
science. And when it comes to measurement what could be more
basic than the measurement of the dimensions of the space in
which we live? To accomplish this fundamental task, we may
use my 6-inch piece of plastic. Lasers, radar or even a global
positioning system might be required for more precise or long
distance measurements. To measure distances to faraway stars,
we measure the red shifts in the light coming from those stars.
Instead of dwelling on such exotic measurements, let''s just take a
closer look at my ruler. It has two scales, the top one in inches,
the lower scale in centimeters. As an American scientist, I''m
quite comfortable with both the metric and the English system of
units but only in certain contexts. I would be most distressed if
the red markers implanted on the fairways of Spooky Brook golf
course indicated 91 meters instead of 100 yards. (A pox on you
cynical readers who say that it wouldn''t matter whether I chose
my pitching wedge or my 9-iron, I wouldn''t get on the green in
either case!) I never have felt totally comfortable driving in
Europe at 100-120 kilometers an hour, yet have no qualms about
driving the equivalent 60-70 miles an hour on our freeways here
in the U.S. It''s clear that most Americans share my discomfort
with the metric system in our everyday lives. Otherwise, why
are we still using the English system when President Gerald Ford
signed the Metric Conversion Act of 1975?
Way back in 1790, Thomas Jefferson, then Secretary of State,
recommended that we employ a decimal system, which was
adopted for our currency. You might think that we would also
have wanted to break away from the English measures of
distance as well. In France, about to undergo its own revolution,
an effort began in 1792 to define a new unit of measurement
called the meter, which gave rise to the metric system. In 1821,
John Quincy Adams pleaded the case for adoption of the metric
system in a report to Congress but nothing changed. The
November/December issue of American Heritage suggests the
reason for our stubbornness in an article by Andro Linklater
titled "The Measurement That Built America". Oddly, Jefferson
himself may be the cause of our reluctance to adopt the metric
system thanks to a suggestion he made in 1784.
The fruit of Jefferson''s suggestion is something you have seen
many times if you have flown over the U.S. from coast to coast.
Linklater calls it "one of the most astonishing human constructs
on earth." This construct is based, not on the number 10 as in the
decimal system, but on the number 4, a surprise to me. I am
accustomed to the use of the number 2 in the binary coding for
computers but 4 didn''t ring any bells for me. Of course, I hadn''t
realized that the length of a surveyor''s chain was typically 22
yards. If you still don''t get it, as I didn''t, let''s go back to England
in the sixth century or so and the "rod". A rod is 16 and a half
feet and 4 rods make 22 yards. Back in those days, it was
considered that a good day''s work for a farmer was tending to 4
square rods of land. If that farmer worked 40 days on plots of
that size, the amount of land he cultivated was an acre. A square
mile encompasses 640 acres.
So what does all this have to do with Jefferson? His 1784
suggestion sounds pretty simple and at first blush not all that
revolutionary. His proposal to initiate a public-land survey led to
the Northwest Ordinance calling for "disposing of lands in the
western territory." The idea was to lay out a grid of lines east-
west and north-south, the lines to be 6 miles apart. The resulting
"townships" of 36 square miles (6 miles x 6 miles) were then to
be split up into 36 one square mile sections and these sections
were to be auctioned off. This grid of parcels of land was a
money machine for the Federal government, the proceeds of the
auctions providing money to pay off the Revolutionary War debt.
The money also would finance the building of roads, universities
and the infrastructure needed for the new nation.
Getting right to work in September 1785, one Thomas Hutchins
got out his 22-yard long surveyors chain on the west bank of the
Ohio River and went to work. The square mile sections, with 640
acres, could be split up into quarters, eighths and sixteenths and,
if you do the math, you''ll see that the magic number of 40 acres
turns out to be the basic unit. Once in a while, even today, you
might hear someone talk about tending the "back forty", typically
in a joking manner. But the standard survey was no joke. The
teams of surveyors, and their support crews with their axes and
other instruments to clear the way, spread out west from the Ohio
folding and unfolding their chains all across the country. The
square grid patterns of roads and farms and city blocks that you
see from your plane window are the result.
These unheralded heroes of the survey carried the chains through
foul weather, swamps and forests, up and down hills and
mountains, etc. Each unit of land was registered at a federal land
office and sold. Abraham Lincoln took a big step forward with
the Homestead Act that offered 160 acre plots (4 of those 40-acre
parcels) free to anyone who would build a cabin and work the
land for five years. This was a very good deal for all but the
Native Americans who suffered the consequences of the
government''s generosity to the farmer/cabin builders.
The American Heritage article makes the point that this
measurement of our land and its disposition played a huge role
aside from determining the geometrical shapes of our nation.
When a person took possession of that 40 acres by registering the
plot, he or she forged a tie to the federal government not only as
the grantor of the land but also as the protector of the right of the
new landowner to the land. The fact that anyone could own a
parcel of land was in distinct contrast to the situation elsewhere,
where the wealthy elite had first dibs on any available land. The
survey prompted true democracy and the right of the "common"
man to property ownership.
This system based on the number 4 is such an inbred part of our
society that it''s no wonder we have resisted the conversion to the
metric system. Yet, what is the basis of the English system? It''s
certainly an arbitrary unit, the foot, which apparently was based
initially on just that - the foot! Actually, the foot came from the
Romans when they occupied England and they in turn got it from
the Egyptians. It''s certainly obvious that feet aren''t all that
uniform in length and that a better standard was needed. Soon
after the U.S. standard survey began, political and measurement
revolutions were brewing in France.
The French decided that a new measure was needed that would
be based on the dimensions of the earth itself, making this
"metric" system appropriate for the whole world to adopt. The
metric system would be based upon the meter, which was to be
exactly one ten-millionth of the distance from the North Pole to
the Equator. A book, "The Measure of All Things" by Ken
Alder, describes the trials and tribulations of two French
astronomers, Jean-Baptiste-Joseph Delambre and Pierre-
Fran ois-Andr M chain who set out to perform this lofty
measurement. I have not read the book but a review of the book
by Timothy Ferris in the October 13 New York Times details
some of the trials and tribulations of these intrepid measurers.
Their mission was to make a series of surveys that straddled a
line of longitude extending from Dunkirk to Barcelona in Spain.
By making a series of triangular plots they somehow were going
to come up with the exact distance of this section of the
circumference of the earth. Perhaps you''re wondering, as did
many skeptics, why not just make a couple marks on a bar of
metal, call it a meter, and be done with it? But the effort was
funded, with Louis XVI signing their papers. This proved to be a
problem. Poor Louis soon lost his throne, not to mention his
head, and those papers almost led to Delambre''s execution by a
menacing mob. I found it amusing, or amazing, that Delambre
saved his own head by giving a lecture on popular science in the
town square! Other problems followed but Delambre soldiered
on.
Going in the opposite direction, M chain suffered a near fatal
accident when a friend demonstrating a pump in a pumping
station allowed the pump handle to fly back and nearly kill
Mechain. The poor guy ended up essentially going mad over this
and other indignities not to mention the fact that his
measurement of the latitude of Barcelona was in error, thanks to
errors in certain astronomical tables. Delambre finally published
a treatise on the foundations of the metric system that exposed
another error that made the whole mission somewhat of a Don
Quixote affair. The earth isn''t really perfectly spherical. The
skeptics were right - just make two marks on a bar of platinum
and be done with it. Which is what happened in 1799.
Nevertheless, Napoleon Bonaparte was prescient in his laudatory
comments on the work of Delambre and M chain. He said,
"Conquests will come and go, but this work will endure." Sure
enough, the metric system is now officially employed by every
nation in the world except the U.S., Myanmar and Liberia.
Jefferson no doubt would have been shocked to find that his
survey started something that would lead to us being a Third
World country as far as our weights and measures are concerned.
Apropos of Veteran''s Day, I once again salute my personal
heroes, William Guyer and Lorraine Fetrow. Bill, the kid across
the street, was killed in World War II when, as I recall, his plane
went down in Myanmar, known then as Burma. Lorraine,
"Shinny" to us, his high school classmates, parachuted into
France on D-Day. As a result of his wounds, he spent the rest of
his courageous and inspirational life as a paraplegic. How to
measure the gratitude we in America owe our veterans?
Allen F. Bortrum
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