Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Close view of area in upper right view. Incandescent area in upper left is enlarging, becoming brighter, and acquiring a quivering jello-like texture that you almost want to touch. Mullite tube is inserted in vent in lower right.
Public Domain.
