He that shall fill a yielding soft body well with air or water, will quickly find its resistance. And he that thinks that nothing but bodies that are hard can keep his hands from approaching one another, may be pleased to make a trial, with the air inclosed in a football.
Gorputz dilatagarri eta bigun bat airez edo urez betetzen duenak, laster egiaztatuko du haren gogortasuna. Eta uste duenak gauza gogorrak bakarrik direla bere esku bata bestera hurbiltzea galarazten dutenak, egin dezatela aproba baloi baten barruko airearekin.