From his neck down a man is worth a couple of dollars a day, from his neck up he is worth anything that his brain can produce.

People who will not turn a shovel full of dirt on the project (Muscle Shoals Dam) nor contribute a pound of material, will collect more money from the United States than will the People who supply all the material and do all the work. This is the terrible thing about interest.

I never once failed at making a light bulb. I just found out 99 ways not to make one.

Maturity is often more absurd than youth and very frequently is most unjust to youth.

It is very different to make a practical system and to introduce it. A few experiments in the laboratory would prove the practicability of system long before it could be brought into general use. You can take a pipe and put a little coal in it, close it up, heat it and light the gas that comes out of the stem, but that is not introducing gas lighting. I'll bet that if it were discovered to-morrow in New York that gas could be made out of coal it would be at least five years before the system would be in general use.

Every wrong attempt discarded is another step forward

I have better use for my brain than to poison it with alcohol. To put alcohol in the human brain is like putting sand in the bearings of an engine.