On Tue, 12 Jan 1999, Alice Campbell wrote:

> Peter wrote:
>
> > You can easily simulate the real thing in the lab using a piston to slide
> > inside the tube instead of getting wet with goo and hanging upside down in
> > smelly petrol tanks. You can also calibrate for temperature like this, as
> > the temperature of the air, and not of the liquid counts (but also
> > air pressure).
>
> or  build an electronic slide whistle for the whistiling-impaired?

Laugh, laugh, once upon a time mechanics checked on the level in
inaccessible tanks by blowing past the open ends of aeration tubes or
whacking them with a wooden stick (hammer handle)...

Peter