Heavier-than-air flying machines are impossible.

Do not imagine that mathematics is hard and crabbed, and repulsive to common sense. It is merely the etherealization of common sense.

Christianity without the cross is nothing. The cross was the fitting close of a life of rejection, scorn and defeat. But in no true sense have these things ceased or changed. Jesus is still He whom man despiseth, and the rejected of men. The world has never admired Jesus, for moral courage is yet needed in every one of its high places by him who would "confess" Christ. The "offense" of the cross, therefore, has led men in all ages to endeavor to be rid of it, and to deny that it is the power of God in the world.

Radio has no future." "X-rays are clearly a hoax". "The aeroplane is scientifically impossible.

Nothing can be more fatal to progress than a too confident reliance on mathematical symbols; for the student is only too apt to take the easier course, and consider the formula not the fact as the physical reality.

You know only insofar as you can measure.

Although mechanical energy is indestructible, there is a universal tendency to its dissipation, which produces throughout the system a gradual augmentation and diffusion of heat, cessation of motion and exhaustion of the potential energy of the material Universe