Friday June 1st. 1787.
At 11, we had another lecture upon the optical instruments; the solar microscope,1 the telescope, the cylindric mirror,2 and the magic lantern came under consideration; we should have seen likewise the camera obscura, but the Clouds overshadowed the Sun so much, that the effect could not take place. I carried down my part to the president, for approbation: was not quite so indolent the whole day, as I have been two days past.
1. The solar microscope was mounted on a window shutter and used in a darkened room; a mirror reflecting sunlight through the instrument projected the image of the specimen on the wall (David P. Wheatland and I. Bernard Cohen, A Catalogue of Some Early Scientific Instruments at Harvard University Placed on Exhibition in the Edward Mallinckrodt Chemical Laboratory, February 12, 1949, Cambridge, 1949, p. 31).
2. Probably an anamorphoscope, or semicircular mirror. When purposefully distorted drawings were viewed through the mirror, they appeared regular and properly proportioned. The instrument was used for demonstration rather than practical purposes (David P. Wheatland, The Apparatus of Science at Harvard, 1765–1800, Cambridge, 1968, p. 124–125).