This physicist studied the Fraunhofer lines and used them to  devise the law named for him, which states that any incandescent  solid, liquid, or gas under high pressure gives a continuous  spectrum, 
This physicist studied the Fraunhofer lines and used them to  devise the law named for him, which states that any incandescent  solid, liquid, or gas under high pressure gives a continuous  spectrum, and that specific elements emit a specific series of  lines. He is also known for his work with electricity.
This physicist studied the Fraunhofer lines and used them to  devise the law named for him, which states that any incandescent  solid, liquid, or gas under high pressure gives a continuous  spectrum, and that specific elements emit a specific series of  lines.
Gustav Kirchoff