Never put off till to-morrow what you can do to-day. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Never trouble another for what you can do yourself. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Never spend your money before you have it. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Never buy what you do not want, because it is cheap; it will be dear to you. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Pride costs us more than hunger, thirst, and cold. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

We never repent of having eaten too little. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

When angry, count ten, before you speak; if very angry, a hundred. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

I tremble for my country when I reflect that God is just; that his justice cannot sleep forever. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

In matters of style, swim with the current; in matters of principle, stand like a rock Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

The man who reads nothing at all is better educated than the man who reads nothing but newspapers. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

We hold these truths to be self-evident: that all men are created equal; that they are endowed by their Creator with certain unalienable rights; that among these are life, liberty, and the pursuit of happiness. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Whenever you do a thing, act as if all the world were watching. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Merchants have no country. The mere spot they stand on does not constitute so strong an attachment as that from which they draw their gains. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

He who knows best knows how little he knows. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Don't talk about what you have done or what you are going to do. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

It takes time to persuade men to do even what is for their own good. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

It is error alone which needs the support of government. Truth can stand by itself. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Advertisements contain the only truths to be relied on in a newspaper. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Ignorance of the law is no excuse in any country. If it were, the laws would lose their effect, because it can always be pretended. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Such ignorance is sometimes called "plausible deniability".

If ignorance is bliss, why aren't more people happy? Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Religious leaders will always avail themselves of public ignorance for their own purpose. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

I tremble for my country when I reflect that God is just; that his justice cannot sleep forever. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Experience demands that man is the only animal which devours his own kind, for I can apply no milder term to the general prey of the rich on the poor. Thomas Jefferson (American statesman, diplomat, scientist and 3rd President of the United States from 1801-1809) .

Mathematically, the catenary curve is the graph of the hyperbolic cosine function. Wikipedia.
Another name for a "catenary" is an "alysoid" from the Greek word for chain.

From the Latin word, the mathematical equation called a "catenary" is name as the shape a chain (or rope) takes when suspended between two points. Power lines take this shape, as do parts of spider webs. A catenary curve appears somewhat like a parabola, but is not exactly a parabola shape.

President Thomas Jefferson is credited with naming the "catenary" curve.

More: Waltzing out of chains