This may be a cryptogram, or an ideographic cypher.

Just a moment, now; don't speak to me." He sat down at the desk and figured laboriously for nearly twenty minutes, working out the inscription in cypher, while Kit stared at him delightedly.

After all, it was rather gratifying, she thought, to have somebody in the family who could take a little remark made thousands of years ago in old Egypt and make sense out of it to-day.

She waited patiently until he had finished.

His hands were trembling as he reached for the urn.
"The circle," he repeated, "the circle.