Science: Matching Machine

In France, wine-tasters sip wines, let their tongues tell them whether the fluid is bound for a plebian carafe or a gentleman’s cellar. Were it not for whiskey-tasters England’s famed blenders would be unable to produce a uniformly good product year in, year out. On equally skilled men depends the fact that all vermilion dyes are uniform, that azure satins are azure. But foibles of the color-matcher’s eyes, which tire quickly, make them expensive to their employers.

A new machine, on the market next week, will doubtless throw scores of color matchers out of work. It will perform their function with more exactness, will cost less and, biggest advantage of all, it will not depend on daylight for its accuracy. The heart of the machine, invented by New York University’s able young physicist Dr. Harold Horton Sheldon, is a photoelectric cell.

Light reflected from two samples of the same cloth placed in the machine, passes into the cell, gives an electrical impulse which is indicated by a galvanometre. The indicator hand is then set at zero, the unknown sample is introduced. If the hand again points to zero the match is perfect. If it varies to the right the second sample is too dark, to the left, too light. A variation of three calibrated scale divisions is considered a passable commercial match.