problem was that the whole supposition rested on the slender
assumption that the figure 1836 did, in fact, denote the pro-
ton-electron mass ratio and was not merely a coincidental reference
to something completely different. They needed a second source of
information to check it against.
When Hunt talked to the mathematicians one afternoon, he was
surprised to learn that they were unaware that the chemists and
anatomists in other departments had computed estimates of surface
gravity. As soon as he mentioned the fact, everybody saw the
significance at once. If the Lunarians had adopted the practice
that was common on Earth-using the same units to express mass and
weight on their own planet-then the numbers in the table gave
Lunarian weights. Furthermore, there was available to them at least
one object whose weight they could estimate accurately:
Charlie himself. Thus, since they already had an estimate of
surface gravity, they could easily approximate how much Charlie
would have weighed in kilograms back home. Only one piece of
information was missing for a solution to the whole problem: a
factor to convert kilograms to Lunarian weight units. Then Hunt
speculated that there could well be among Charlie’s personal
documents an identity card, a medical card-something that recorded
his weight in his own units. If so, that one number would tell them
all they needed to know. The discussion ended abruptly, with the
head of the Mathematics section departing in great haste and a
state of considerable excitement to talk to the head of the
Linguistics section. Linguistics agreed to make a special note if
anything like that turned up. So far nothing had.
Another small group, tucked away in offices in the top of the
Navcomms HQ building, was working on what was perhaps the most
exciting discovery to come out of the books so far. Twenty pages,
right at the end of the second book, showed a series of maps. They
were all drawn to an apparently small scale, each one depicting
extensive areas of the world’s surface-but the world so depicted
bore no resemblance to Earth. Oceans, continents, rivers, lakes,
islands, and most other geographical features were easily
distinguishable, but in no way could they be reconciled with
Earth’s surface, even allowing for the passage of fifty thousand
years- which would have made little difference anyway, aside from
the size of the polar ice caps.
Each map carried a rectangular grid of reference lines, similar to
those of terrestrial latitude and longitude, with the lines spaced
forty-eight units (decimal) apart. These numbers were presumed
to denote units of Lunarian circular measure, since nobody could
think of any other sensible way to dimension coordinates on the
surface of a sphere. The fourth and sevent~i maps provided the key:
the zero line of longitude to which all the other lines were
referenced. The line to the east was tagged “528” and that to the
west “48,” showing that the full Lunarian circle was divided into
576 Lunarian degrees. The system was consistent with their
duo-decimal counting method and their convention of reading from
right to left. The next step was to calculate the percentage of the
planet’s surface that each map represented and to fit them together
to form the complete globe.
Already, however, the general scheme was clear. The ice caps were
far larger than those believed to have existed on Earth during the
Pleistocene Ice Age, stretching in some places to within twenty
(Earth) degrees of the equator. Most of the seas around the
equatorial belt were completely locked in by coastlines and ice. An
assortment of dots and symbols scattered across the land masses in
the ice-free belt and, more thinly, over the ice sheets themselves,
seemed to indicate towns and cities.
When Hunt received an invitation to come up and have a look at the
maps, the scientists working on them showed him the scales of
distance that were printed at the edges. If they could only find
some way of converting those numbers into miles, they would have
the diameter of the planet. But nobody had told them about the
tables the Mathematics section thought might be mass-unit
conversion factors. Maybe one of the other tables did the same