The Natural Philosopher wrote:

Last might I walked over to a friend of mine, and later on he ran me
back in his car, when we discovered a rear tyre was nearly flat. I
pumped it up with me trusty Halfords inflator, but I could hear air
hissing out - we both did - and there was a draught coming out of the
tread at one point. However it was dark so I left his car there, ran him
home in mine, and this morning went out to see how flat the tyre was.

Well it wasn't. Flat. The hiss wasn't there, there was no sign of a
hole..in the location where the air had been coming out (edge of the
tread)...

Perhaps some of that rubber-solution-like material
intended to mend small punctures
had been inserted in the tyre at some point?

--
Timothy Murphy
gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin