A Most Improved type microscope with advanced features

An early achromatic (and non-achromatic) transitional microscope, c. 1830

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830. View of the sub-stage.

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830. Vew of the substage.

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830. Alternate eyepiece mounted.

    The upper portion of the tube having the double eye-lens and field lens can be removed and replaced with an adapter that can accommodate an alternate set of Huygens eyepieces. Two are provided (one lacking its bottom lens) having the outer lacquered portion with a bayonet fitting.

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830. Accessories.

Among the accessories are seven non-achromatic objectives, two achromatic objectives, an eyepiece with field lens that is mounted on the tube, and two alternate Huygens eyepieces that fit via an adapter that attaches to the tube. Other accessories are a free-standing bullseye condenser, three dark wells that mount on a dark well holder attached to the bottom of the stage, a focusing achromatic(?) condenser, which mounts with a bayonet fitting onto the bottom of the stage, a stage forceps, and hand forceps.

    A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830. Alternate pieces and achromatic objectives.

    Achromatic objectives and Huygens eyepieces

 

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830. Stored within its case.

A Most Improved type microscope with advanced features. An early achromatic (and non-achromatic) transitional microscope, c. 1830/ Wood storage case.

 

The microscope now known as the "Most Improved" model has its origin in the "Universal Compound Microscope" introduced by George Adams Jr. in the late 18th century and described in his 1787 publication, Essays on the Microscope. By the end of the century, the copyright to Adams' books and designs were purchased by the firm W. & S. Jones of London. They began, in 1798, the production of a microscope with a similar design, which they called the "Jones Most Improved Microscope". A folding tripod base from which rises a pillar terminating in a compass joint for inclination characterizes this design. Attached to the other end of the joint is a bar that holds the tube, stage, mirror, and sometimes a simple lens to serve as a condenser. The focusing mechanism consists of a rack embedded in the bar and pinion attached to the stage; this arrangement moves the stage in and out of focus. The mirror can also be positioned on the bar by sliding it up and down. The optics in this model usually consist of a double eye-lens and a field lens located within the body of the tube; the objectives are non-achromatic. This design became very popular and was produced by many other English opticians during the first part of the 19th century.

Overall, the microscope shown on this page, which is unsigned by its maker, conforms to a "Most Improved" design, albeit one with some advanced features among which are a mechanical stage, a screw fine adjustment that moves the stage in addition to the rack and pinion coarse adjustment, a focusing sub-stage with condenser (achromatic?), both achromatic and non-achromatic objectives, an alternate eyepiece arrangement, a double sided mirror, and a telescoping pillar.

During the period around 1830-1840 the English microscope was undergoing a rapid evolution from the non-achromatic instruments produced in the previous century to the achromatic microscopes that became more common within the second quarter of the 19th century. During this evolutionary period, some of the microscopes that were produced are often now referred to as "transitional"; that is, they represent a design that is midway between the older and newer forms. The microscope shown on this page is clearly one of these.

Certain features of this microscope are reminiscent to those produced later by Hugh Powell and Andrew Pritchard suggesting that possibly this microscope is an early product of one of these individuals. It is known that Powell, for a time, made instruments for the trade before beginning to sign his own microscopes around 1840.


On a brass placque inset into the cover of the case is worn engraving with the name of a previous owner, either Tho's Bund or Tho's Brind. In the London trade directories, there is a listing for a Thomas Brind (1793-1870) as follows: "Brind Thos. Coal & coke mercht, 24 Winchester wf, City rd. basin", possibly the original owner of this instrument?

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