IN THE Museum of Natural History at Soleure, in Switzerland, there is said to be a bird's nest made entirely of steel. There are a number of clockmaking shops at Soleure, and in the yards of these shops there are often found lying disused or broken springs of clocks. One day a clock-maker noticed in a tree in his yard a bird's nest of peculiar appearance. Examining it he found that a pair of wag-tails had built a nest entirely of clock springs. It was more than four inches across and perfectly comfortable for the birds. After the feathered architects had reared their brood, the nest was taken to the museum, where it is preserved as a striking illustration of the skill of birds in turning their surroundings to advantage in building their nests.