Spectroscope, about 1920
Spectroscopic Apparatus, Steel engraving, 1869
Chart showing the spectra of different types of blood samples, 1894
Henry Enfield Roscoe, Ph.D., On Spectrum Analysis, New York, 1869
Beckman DU Spectrophotometer, about 1950
Diagram of the Model DU Spectrophotometer, showing Mounting Block, Cell Compartment, Phototube Housing and Lamp Housing detached from the Monochromator
Beckman DU Spectrophotometer, about 1950
Beckman DU spectrophotometer, about 1950
The DU spectrophotometer measures the amount of ultraviolet light absorbed by a substance. Developed by Arnold Beckman at National Technical Laboratories to measure the amount of vitamin A in food, it came to be widely used to identify and measure a variety of substances. The DU spectrophotometer was one of several revolutionary devices invented by Beckman: the first "black boxes" in the chemical laboratory. It revolutionized laboratory work by replacing labor-intensive and bulky (and openly visible) chemical procedures with a simple, boxed electronic instrument in which only input and output could be seen.
DeWitt Stetten, Jr., Museum of Medical Research, National Institutes of Health
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Spectral detection

In the 1850s, Robert Bunsen and Gustav Kirchhoff devised the first working spectroscopes. Two decades later, Georg Dragendorff and other scientists began using spectroscopy for medical research and criminal investigations.

The fields of toxicology and serology—the study of blood and other body fluids—were the first to benefit. A small specimen of blood, subjected to a flame from a Bunsen burner, gave off light that could be subjected to spectroscopic analysis. This analysis could reveal the presence of carbon monoxide and other poisons.

Black Box Effect

In the 1940s the Beckman spectrophotometer revolutionized the laboratory. Encased in a metal container, the device occupied less counter space than conventional bench apparatus, and hid the procedures inside a box. A technician placed a specimen on a slide, inserted it into the instrument, and recorded the readings.

Historians of science theorize that "black box" devices are basic to modern laboratory practice. A device and its output replace the hand, eye, and judgment of the scientist. The standardized inner workings and seemingly objective output of the black box can more easily evade or withstand legal scrutiny.