The following was extracted from The National Cyclopedia of American Biography, vol. XIII, 1906.

TOLLES. Robert B., lensmaker, was born in Winchester, Litchfield co., Conn., about 1825, son of Elisha and Harriet Tolles. His father was an inventor, but from lack of funds was unable to develop any of his ideas. The son was educated in the common district school and passed his boyhood at home and on his grandfather's farm near by, working to aid in supporting the family. In 1813 while in Canastota, N. Y., he accidentally visited the workshop of Charles A. Spencer, and soon afterwards he entered the service of the celebrated lensmaker as an apprentice. Under the instruction and guidance of this remarkable man young Tolles learned the special business in which he displayed such genius. In 1858 he started in business on his own account in Canastota, removing to Boston, Mass., nine years later, where he organized the Boston Optical Works. He was affiliated with this company the remainder of his life, for the first four years as superintendent and thereafter as sole proprietor. His one aim in his business was the improvement of the microscope, and his achievements in this line prove that he was well qualified for the task by his " great theoretical and practical knowledge of the science of optics, united with mechanical and inventive genius and marvelous skill of eye and hand." While still in the service of Mr. Spencer he devised a cover correction for objectives, and invented and patented a solid eye-piece. In 1858 he made his first immersion objectives, and objectives with two fronts one to be used as an immersion and the other dry, and in 1866 he obtained a patent for a stereoscopic binocular eye-piece. He invented many other devices and appliances for the microscope, as well as some telescopes remarkable for their short focal length in proportion to the diameter of object-glass and for their defining and penetrating power. The great step, however, which placed him, together with Charles A. and Herbert R. Spencer, at the head of his profession, was the construction in 1873 of an immersion one-tenth objective with an aperture greater than that corresponding to infinitely near 180 degrees in air. It was a three system lens which had an aperture of more than 110 degrees in balsam, or 1.25 N. A., and which is said to have produced " a revolution of opinion and practice among users and makers of microscopes all over the world." At the same time he also made his first lens of the duplex front formula one-fifth inch glycerine immersion of 110 degrees balsam angle. On Aug. 10, 1883, he was elected an honorary member of the American Society of Microscopists. Notwithstanding his valuable achievements, the last ten years of his life were years of suffering and hardship; he worked at his bench when he should have been in his bed, denying himself all the luxuries and many of the comforts of life. He greatly suffered from a disease of the lungs which was contracted at an early age and which caused his death. During his last illness, he had a microscope brought to his bedside and there on his deathbed examined and tested the lenses. Only a few minutes before his death he was occupied in correcting the degrees of aperture of an imaginary lens and when he reached 150 degrees, he stopped, turned his head and said faintly, "Goodbye. He was married in 1853 to Freelove S. Dickey, but was left a widower a few months later. He died in Boston, Mass. Nov. 17, 1883.

For a discussion of the life and work of Robert B. Tolles see: Three American Microscope Builders published by the American Optical Company 1945.

Other examples of the Tolles Student's microscope are located at the following institutions: