Francis L. Hawks,
Natural History
“ It was a long time that men lived before they found out a mortar that would remain, and grow hard under water. When they want to build a wall that is to be under the water, they use a cement which is called pozzolana; it is made of lava out of a volcano, and is water-proof. Our caddis-worm has a cement too, which is better than pozzolana, and though it has been tried, it cannot be melted or dissolved in water. Here is a drawing of the stone nest of a caddis-worm. ”
