What is in the red?

The term, "in the red" describes when something is not functioning properly. For example, if you're running a business successfully; then your would be considered to be "in the black". Because your accountant would be using a black pen in the ledger. On the other hand, he would use a red ink pen to record a deficit. Thus the term, "in the red".

The gauges on a boiler have a section showing red to indicate that when the needle enters this area, the boiler is reaching the upper limits in its ability to contain the pressure. Early boilers would simply explode when this occurred. Now, of course, boilers are designed to blow their safeties when too much pressure builds up.

This innovative design has saved many lives over the years.