high_rolla writes "How many of you have actually used a slide rule? The slide rule was a simple yet powerful and important tool for engineers and scientists before the days of calculators (let alone PCs). In fact, several people I know still prefer to use them. In the interest of preserving this icon we have created a virtual slide rule for you to play with." Wikipedia lists seven other online simulations.
When bad men combine, the good must associate; else they will fall one by one,
an unpitied sacrifice in a contemptible struggle.
- Edmund Burke