A Vertical Achromatic Microscope, By Andrew Pritchard. England, Circa 1840-1845. Model: 423 Signed to the tube and shaped tripod base 'Andrew Pritchard, 162 Fleet Street, London', with concave mirror in gimbal mounted to the tripod base, with simple stage, rack and pinion focusing to rear of triangular bar, limb at top to accept compound body tube, contained in an associated mahogany case with two objectives, two achromatic objectives in signed containers, stage forceps, and a glass slide with head of wand louse. Measurement: H. 32 cm. catalogue Note: Andrew Pritchard made numerous, substantial impacts on microscopy during the second quarter of the nineteenth century. Soon after completing his apprenticeship, Pritchard received acclaim for his production of microscope lenses that were made of diamond, sapphire, and other jewels. The best of these jewel lenses produce little-to-no chromatic aberration. catapulted by that success, Pritchard built a broad retail and publishing business. As with other microscope manufacturers/retailers, Andrew Pritchard's earliest instruments were probably produced by his own hand. As the business increased, brasswork and optics would have been assigned to in-house craftsmen or outsourced to subcontractors. Born in London in December, 1804, he was almost entirely brought up by his grandfather, one of the chief cashiers in the Bank of England. On the foundation of the Mechanics' Institution in Southampton Buildings, by Dr. Birkbeck, Mr. Pritchard entered as a student. The microscope was then a very imperfect instrument, and Mr. Pritchard worked hard at the achromatisation of lenses, and was the first to propose to take advantage of the high refracting power of the diamond, ruby, and sapphire for the manufacture of single lenses, these giving good definition without the coloured borders incidental to ordinary flint glass. Between the years 1829 and 1837 he published several works on the microscope, in which he was aided by Dr. Goring, particularly the "Microscopic Illustrations," "Micrographia," and the "Microscopic Cabinet," for which several good plates were prepared. In the year 1836 Mr. Pritchard was elected a Member of the Royal Institution, being proposed by Faraday, and in the previous year joined the British Association at Dublin, taking part in the deliberations of this body until comparatively recent times. In 1873 the Royal Society of Edinburgh conferred upon him their fellowship, in recognition of his scientific attainments, as evidenced by his great work, the "History of Infusoria," a memorial of patient industry and biological research". Pritchard's entry in The Dictionary of National Biography: "Pritchard, Andrew (1804-1882), microscopist, eldest son of John Pritchard of Hackney, and his wife Ann, daughter of John Fleetwood, was born in London on 14 Dec. 1804. He was educated at St. Saviour's grammar school, Southwark, and was afterwards apprenticed to his cousin, Cornelius Varley, a patent agent and brother to John Varley, the artist. On the expiration of his apprenticeship he started in business as an optician, first at 18 Picket Street, then at 312 Strand, and afterwards at 162 Fleet Street. He retired from business about 1852, and died at Highbury on 24 Nov. 1882. He married, on 16 July 1829, Caroline Isabella Straker. Brought up with the "independents", Pritchard later in life associated with, though he never actually became a member of, the sect known as Sandemanians, and it was in connection with that body he first made the acquaintance of Faraday. He finally became a unitarian, and in 1840 joined the congregation at Newington Green, a connection which lasted throughout his life. He was greatly interested in all the institutions connected therewith, and was treasurer of the chapel from 1850 to 1872. Pritchard early turned his attention to microscopy, and in 1824, while still with Varley, he, at the instigation of Dr. C.R. Goring, endeavoured to fashion a single lens out of a diamond. Despite the discouragement of diamond-cutters, he ultimately succeeded in 1826. He also fashioned simple lenses of sapphire and of ruby. His practical work on the microscope, however, was less productive of lasting results than his literary labours on the application of the instrument to the investigation of microorganisms. His "History of the Infusoria" was long a standard work, and the impetus it gave to the study of biological science cannot be readily overEstimated". Literature: Microscopic Objects, Animal, Vegetable and Mineral: With Instructions for Preparing and Viewing Them. By Andrew Pritchard. Published by Whittaker and Co., Ave Maria Lane. London. 1847. Page 173-179. Estimate: 500-800