In spite of the scientific progress of the world during the present century there are still many secrets of the ancients that defy solution.

Thousands of years ago the Egyptians used to embalm the bodies of their rulers in a way that, so far as known, cannot be equalled today. Modern science is endeavoring to recapture this lost knowledge.

Lanolin, the fat made from the wool of sheep, was manufactured and used by the Greeks two thousand years ago. Here again the secret was completely lost and quite forgotten until rediscovered late in the nineteenth century.

In 1908 an inventor named Simpson, of Blackburn, England, patented a liquid that has peculiar properties. When painted with it, a damp wall becomes dry, while iron-work covered with it cannot rust. This liquid was pronounced by leading engineers to be another old Roman secret lost for some seventeen hundred years.

Sheffield, England, turns out what is claimed to be the finest steel in the world. Yet even Sheffield, with all her science has never matched the steel of the sword blades made by the Saracens a thousand years ago, and the Saracens never had such machinery as modern steel makers possess.

The Romans made cement at least as good as any today, yet this secret was lost for more than a thousand years and was rediscovered only about a century ago. It was the Romans, too, who made that wonderful pottery called "terra sigillata." This was rediscovered by the Batavian potter, Fischer, in quite recent times.

As all artists know, there are pictures three hundred years old which need only cleaning to show as clean and light as on the day they were finished.