e now to explain the method of defense against the light-ray. In
theory I only vaguely understood it. In practice it was simple and, like
most defenses, only partially effective.

Bob Trevor, has already mentioned it--the suits of black cloth he saw in
the Mercutian camp in Wyoming. It was not, as he had afterward supposed, a
dye for fabrics. Instead, it was the thread of a worm--like our silk
worm--which in its natural state was black and was impervious to the ray.
By that I mean a substance whose molecules increased their vibration rate
only slightly from a brief contact with the ray.

It was only partly efficacious, for after an exposure of a minute or more
the intense heat of the ray was communicated. It then became partly
penetrable, and anything close behind it would be destroyed.

We had under manufacture at this time a number of protective devices by
which this substance might be used. Boats had, in the past, been equipped
with a sort of shield or hood in front, making them more or less
impervious to a direct horizontal beam of the light.

Tao's boats which now threatened us were so protected, I was informed by
the girls who reported them. Recognizing the probability of an attack by
us from the air, they also had a covering of the cloth, like a canopy
above them. But as may be readily understood, such protection could be
made only partly effective.

I had already manufactured, at Miela's suggestion, a number of shields for
our girls to carry while in flight. These consisted of the fabric in very
light, almost diaphanous, form, hung upon a flexible frame of very thin
strips of bamboo. It was some twelve feet broad across the top, narrowing
rapidly into a long fluttering tail like a kite.

There was nothing rigid about this shield. Its two or three bamboo ribs
were as flexible as a whip, with the veiling--it was hardly more than
that--fluttering below them almost entirely unsupported. In weight, the
whole approximated one-twelfth that of a girl, not at all a difficult
amount to carry.

Within two hours after the report came--it was near midday--we were ready
to start from the Great City to repel Tao's attack. Our forces consisted
of some six hundred girls, each armed with a light-ray cylinder and a
shield. This was the organization I have already mentioned, fifty squads
of ten, each with a leader; and fifty other girls, the most daring and
expert in the air, who were to act independently.

We had two platf