There was a secret elevator in his room, behind one of the full-length wall charts.
It's a quantum leap ahead of what the wall chart has been.
It uses a wall chart that has several rows of letters.
Between 1877 and 1892, he developed a series of zoological wall charts that have been used worldwide as teaching aids.
Today these wall charts are housed in several different museums.
"Here's what our operating layout will look like," he announced, pointing to a large wall chart.
One day he noticed the wall chart was gone.
You would make a great electronic wall chart of the Domain, eh?
Often they are multi-coloured stars stuck on a wall chart.
He memorized the numbers and crossed to a wall chart.
