Figure 3-45Early Spectroscope In the mid-1850s, Kirchhoff and Bunsen discovered that when a chemical substance is heated and vaporized, the resulting spectrum exhibits a series of bright spectral lines when passed through a slit, lenses, and a prism. This device is called a spectroscope. In addition, they found that each chemical element produces its own characteristic pattern of spectral lines. The lenses focus and magnify the spectrum.