Analysis of Solar Furnace

Solar Furnace
(Left to their own devices young boys can be cruel rascals; strings attached to cats tails is an example.  The solar furnace kept us amused for hours.)

Those thick domed headlight lenses
Make excellent solar condensers
For an optical crucible.

The trick is to make the depth
Of the earth hole equal to the focal length
Of the lens.

The sides are smoothed with water
And the edge close fitting
So nothing can escape.

On the equator the sun is overhead every day,
And peering down we could see the prey
Magnified in the pit.

The center floor became very hot
And woodlice or siafu ants delighted us
When their toes hit the fire .

Ultimately everything went pop
And you could feel this through the earth
As the chamber filled with smoke.

Spiders could hang themselves
Out of danger for a long time
But tumbling they sizzled.