y seemed not so much intent as meditative, and not so
much watchful as interested. When the sergeant and his guest moved past
them, the unrhythmic waverings of the small yellow lights seemed to
change hopefully, as if the machines anticipated being put to use.
Which, of course, was absurd. Mahon machines do not anticipate anything.
They probably do not remember anything, though patterns of operation are
certainly retained in very great variety. The fact is that a Mahon unit
is simply a device to let a machine stand idle without losing the nature
of an operating machine.

The basic principle goes back to antiquity. Ships, in ancient days, had
manners and customs individual to each vessel. Some were sweet craft,
easily handled and staunch and responsive. Others were stubborn and
begrudging of all helpfulness. Sometimes they were even man-killers.
These facts had no rational explanation, but they were facts. In
similarly olden times, particular weapons acquired personalities to the
point of having personal names--Excalibur, for example.

Every fighting man knew of weapons which seemed to possess personal
skill and ferocity. Later, workmen found that certain tools had a knack
of fitting smoothly in the hand--seeming even to divine the grain of the
wood they worked on. The individual characteristics of violins were
notorious, so that a violin which sang joyously under the bow was
literally priceless.

And all these things, as a matter of observation and not of
superstition, kept their qualities only when in constant use. Let a ship
be hauled out of water and remain there for a time, and she would be
clumsy on return to her native element. Let a sword or tool stay unused,
and it seemed to dull. In particular, the finest of violins lost its
splendor of tone if left unplayed, and any violin left in a repair-shop
for a month had to be played upon constantly for many days before its
living tone came back.

* * * * *

The sword and the tool perhaps, but the ship and the violin certainly,
acted as if they acquired habits of operation by being used, and lost
them by disuse. When more complex machines were invented, such facts
were less noticeable. True, no two automobiles ever handled exactly the
same, and that was recognized. But the fact that no complex machine
worked well until it had run for a time was never commented on, except
in the observation that it needed to be warmed up. Anybody would