In some localities, householders are provided with "wheelie bins" for
garden waste.
These bins have a hinged lid.
If a bin is filled with fresh cut grass, and the lid is left propped open
with a stick, on a sunny day* the bin heats up and much moisture
evaporates, causing the contents to
shrink and allowing more
material
to be loaded.
But if it rains**, the rain wets the cuttings and accumulates in the
bin.
Not good.
BorgCo engineers have developd an automatic bin-closer to prevent
this problem. The device consists of a wooden lath, at the end of
which
is a mechanism resembling a mousetrap. This is prevented from
operating by a soluble aspirin tablet, above which is a small funnel.
When it rains, water is collected by the funnel and dripped onto the
aspirin, which dissolves. The spring is released and the arm flips the
lath clear of the bin, allowing the lid to fall shut under the influence
of
gravity***
*Readers in the UK may not be familiar with this.
**Readers in the UK will definitely be familiar with this.
***Gravity not included.