; NESTS OF THE WATER-SPIDER.
"The water-spider builds a house of silk in the shape of a bell, and anchors it to the roots of the grasses that grow several feet under the water. Having finished his dwelling, he proceeds to stock it with air. For this purpose he comes to the surface, takes a bubble of air under his abdomen and carries it to the house, where he releases it, and allows it to rise into the cavity where he wants it. He repeats the operation till he has filled it with air, and then he has a satisfactory home for his family.
; DIVERS IN THEIR ARMOR.
"Now the diving-bell is on this principle, with the advantage of not being stationary, and also with the greater advantage that the air can be renewed when it becomes foul. But the modern armor dispenses with the bell; the head of the diver is covered with an air-tight helmet with a plate of glass in front, so that the man can see what is about him, and the air is kept fresh by means of an air-pump and a flexible tube of india-rubber. There are several forms of this apparatus, some of them having a metallic knapsack, where the air is received before it goes to the helmet, while others dispense with the knapsack, and carry the air directly to the head of the man who is to breathe it. Sometimes, where the depth is slight, and he is not to remain long below, the diver does not use the helmet at all, but simply holds a tube in his mouth, through which a stream of air is driven to him."
Frank asked how the man wearing this armor managed to sink in the water, and retain his perpendicular position. According to his experience, there was a tendency of the feet to fly upwards as soon as the body was in the water, especially where it was salt instead of fresh.