The Awn Of Barley An Hydrometer

The awn of barley is furnished with stiff points, which, like the

teeth of a saw, are all turned towards the point of it; as this long

awn lies upon the ground, it extends itself in the moist air of night,

and pushes forward the barley-corn, which it adheres to in the day; it

shortens as it dries; and, as these points prevent it from receding,

it draws up its pointed end, and thus, creeping like a worm, will

travel man feet from the parent stem. That very ingenious mechanic

philosopher, Mr. Edgworth, once made on this principle a wooden

automaton: its back consisted of soft fir-wood, about an inch square,

and four feet long, made of pieces cut the cross-way in respect to the

fibres of the wood, and glued together; it had two feet before, and

two behind, which supported the back horizontally, but were placed

with their extremities, which were armed with sharp points of iron,

bending backwards. Hence, in moist weather, the back lengthened, and

the two foremost feet were pushed forwards; in dry weather the hinder

feet were drawn after, as the obliquity of the points of the feet

prevented it from receding.