Upon the mouths of these two pieces of hollow wood they tie a piece of a Deers Skin, on each pot a piece, with a small hole as big as a man's finger in each skin.

In the middle of each skin a little beside the holes are two strings tied fast to as many sticks stuck in the ground, like a Spring, bending like a bow.

This pulls the skin upwards.

The man that blows stand with his feet, one on each pot, covering each hole with the soles of his feet.

And as he treads on one pot, and presseth the skin down, he takes his foot off the other, which presently by the help of the Spring riseth; and the doing so alternately conveys a great quantity of wind thro the Pipes into the Furnace.