Enormous dimensions, complicated military calculations, and thousands of vacuum tubes—this was the early supercomputer.

A vacuum tube is just that: a glass tube surrounding a vacuum (an area from which all gases have been removed). What makes it interesting is that when electrical contacts are put on the ends ...

A light source consisting of a long glass tube containing mercury in a partial vacuum. Available in many lengths and several diameters, the tube is lined with a fluorescent phosphor. When the ...