Microtome in box, c. 1770. A microtome is used for cutting thin slices of specimen for microscopic investigation. Alexander Cumming, a clockmaker to George III, invented and made this device. The specimen was put in the hole and was pressed upwards by a screw. The blade slices the specimen at the top which is then pushed up the required amount by the screw. Although the settings are for 1/500, 1/750 and 1/1000 of an inch, the instrument could not actually achieve this degree of accuracy.