Glass

In Toledo I saw a machine plopping volleys of 24-ounce steel balls on glass for store doors-from 18 inches, from 22 inches, from 24 inches, and higher-with never a fracture of the silken surface.

Out at the zoo they coaxed an elephant up on a piece of plate glass supported by blocks under its four corners to have his picture taken. Pachyderm and plate glass came through intact.

Not only impact, but heat and cold fracture ordinary glass. Now they make glass which they lay on a piece of ice and pour molten lead on its top side without cracking it.

Formerly everybody saw "through a glass, darkly," as the Bible puts it, because the best of glass was only approximately transparent.

One New York department store put up "invisible glass" to guard its better costume jewelry. So many shoppers reached out to examine the pieces and bruised their knuckles that the store had to hang a sign, "This is glass."

"What is glass?" I kept on asking.

"A misnomer," said one famed physicist. "You wouldn't order a ton of metal. Don't speak of 'glass,' but of 'glasses.' There are more kinds of glasses than there are of all the metals and alloys combined."

One glass is lighter than aluminum; another is heavier than iron.

At the Corning Glass Works they regularly melt some 300 different glass compositions. Research men there are studying about 30,000 glass prescriptions. In huge stock piles are 110 ingredients to mix with sand in quantities ranging from tons to grams.

A new glass which transmits ultraviolet rays must be so nearly pure that one wrong grain of sand in a ton might make the product defective.

Such glass transmits two types of rays: one generates ozone from the air, the other kills germs. Hospitals use it to "blanket" contagious wards; packing plants buy it to tenderize meats.

With it banks and art galleries can detect fraudulent checks and old masters because ultraviolet rays show up different inks and paints.

Another glass which absorbs infrared rays, and therefore screens heat, is useful in operating rooms, for dentists' instruments, and in windows of trains that run through hot countries.

To control just one quality, color, the Blenko Glass Company in West Virginia has formulas for more than 300 different shades of stained glass for church windows. The mixers compound new hues as artists order them (Color Plates IV and V).

"What is glass?" I asked again.

"Truth is," replied a chemist, "the constitution of glass is about as much of a mystery as the make-up of electricity, We know what we can do with both of them, which is plenty, When we find out what glass really is we should go to town!"

Glass is "going to town" right now, as never before, to meet demands for replacement of metals that have gone to war.

From glass now are made centrifugal pumps…”