Whirls and Fleas

Turbulence is interesting to anyone dealing with flow – any liquid flow, which includes airflow. Mathematician, physicist, pacifist and iceberg-detector LF Richardson wrote:

“Big whirls have little whirls, which feed on their velocity, and little whirls have lesser still, and so on to viscosity.”
LF Richardson (in 1922)
This was a play on Augustus de Morgan’s: 

“Great fleas have little fleas upon their backs to bite ’em,
And little fleas have lesser fleas, and so ad infinitum.
And the great fleas themselves, in turn, have greater fleas to go on;
While these again have greater still, and greater still, and so on”

Augustus De Morgan, A Budget of Paradoxes, 1915


Which in turn, is a rewording of Jonathan Swift’s: 

“So, naturalists observe, a flea
Has smaller fleas that on him prey;
And these have smaller still to bite ’em,
And so proceed ad infinitum.
Thus every poet in his kind
Is bit by him that comes behind”

Jonathan Swift, Poetry, A Rhapsody. 1733


I was reminded of this when I saw a dung beetle with mites on his head in Amanyoni:

and today when an Emperor moth dying on my lawn had some zebra-patterned wasp or fly inspecting him with what seemed to me macabre interest:


Leave a Comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s