Casper Daily Tribune

Value of Sense of Smell Proved in Discovery of the Substance Selenium

Have you an ambition to found a new science? Why not measure a smell? Can you tell whether one smell is just twice as strong as another? Can you measure the difference between one kind of smell and another?

It is obvious that we have very many different kinds of smells, from the odor of violets down to asafetida, but until you can measure their likenesses and differences you can have no science of odor, writes Alexander Graham Bell in Youth's Companion.

In the first place we have to define an odor. Is it an emanation of material particles into the air or is it a form of vibration, like sound? If you can decide that question, you will have the starting point for an entirely new investigation. If odor is an emanation, it could be reflected from a mirror. Light and sound and heat can be reflected. I have even warmed my hands at the reflection of a fire in a mirror of polished metal.

That a cultivation of the sense of smell may be very valuable was proved in the discovery of the substance selenium. In experimenting with the waste products obtained in manufacturing sulphuric acid, a distinguished chemist noticed the characteristic smell of tellurium—an odor that has no counterpart on earth or in heaven.

But the smell was the only indication of the presence of the substance; all the chemical reactions declared that there was no tellurium present in the powder. The chemist therefore concluded that, if no tellurium was present, there must be a new substance there, as yet undiscovered, which resembled tellurium.

When he had extracted from the mass all the materials that he knew were present, he found a residue, which proved to be, as he had suspected, a new elementary substance.

This new substance, which was named selenium, resembled black sealing wax in appearance. In its vitreous form it was a nonconductor of electricity, but when heated almost to the fusing point and allowed to cool very slowly it completely changed its appearance. It acquired a dull, metallic look, like lead: and in that, its crystalline condition, it was a conductor of electricity, but of extremely high resistance. A little pencil of crystalline selenium, not much more than an inch long, offered as much resistance to the passage of the electrical current as 96,000,000 miles of wire, enough to reach from here to the sun. Yet it was a conductor.