It was forbidden to use optical instruments for the time being.
He decided that for such detailed work, they may have had optical instruments.
In it they gave no documentary evidence of optical instruments.
In the second main sections, the results obtained are applied to optical instruments.
This business was soon converted to the manufacture of optical instruments.
When she opened her eyes again, each of them confronted what appeared to be a tiny optical instrument no more than an inch away.
He was known in his time, and is remembered today, for the high quality of his optical instruments.
This level of magnification shows the eye as an optical instrument.
The 94-inch optical instrument would be the largest orbiting telescope.
Many new optical instruments with medical applications were invented during the 19th century.