Andrew Pritchard (b. 1804 - d. 1882) was one of the earliest established commercial providers of microscope slides in London, being in business from the mid 1820s until the late 1850s. He was primarily known and highly respected as a skilled instrument maker, microscopist, and optician, as well as a prolific author. His popular and influential books on optics and microscopy, published beginning in 1827, are considered by many to have played a pivotal role in the further development and commercialization of the microscope. At the same time, they encouraged the popular interest in and investigation of the natural world. His books also contained some of the first lists and descriptions of interesting microscopic objects for study, with methods for their preparation. A savvy businessman, the books also inform readers of the fact that various mounting supplies and materials, as well as professionally prepared examples of many microscopic objects, were available from his retail shops along with his microscopes and other instruments.

Pritchard's name has become associated with several different types of early commercial slides, including those using red sealing wax in their construction and various examples of early "test" slides.  Recent research (published over the last dozen years or so) suggests that, while probably making preparations for his own use and study, Pritchard was likely not the actual maker of the many microscopical preparations that bear his name. It does seem rather unlikely that a successful gentleman of Pritchard's stature and social standing would have spent long days toiling at the workbench to produce commercial quantities of slides for sale. A much more probable scenario would be that he contracted with some of the early London slide makers to provide the inventory he advertised and sold through his shops. Similarity of handwriting and construction style to known early examples prepared by W.H. Darker, C.M. Topping and J.W. Bond suggests that they may have been the slide makers initially supplying Pritchard during the 1830s, while further developing their own name recognition and business interests. This would also explain the wide variation in handwriting that can be seen on slides bearing Pritchard's name: they would have likely been labeled and signed with Pritchard's name by the different makers who were actually mounting the preparations for resale through Pritchard's shop. As regards the "red sealing wax" method of slide construction, an interesting excerpt from Prof. John Quekett's 1848  "Practical Treatise on the Use of the Microscope" concerning slide preparation and "Mr. Darker's Method" clearly attributes the original development and use of the technique to W.H. Darker, although Pritchard did describe the method in his anonymously authored book "Microscopical Objects, Animal, Vegetable, & Mineral " in 1847.

The slides shown below are mostly circa 1830s to 1840s, and while not all are signed, their construction details using methods that Pritchard helped popularize, including the use of red sealing wax as an edge seal and finish, would argue for their inclusion as additional examples of microscopic preparations that might have been sold through his shop.

Two early slides labeled and signed simply "Pritchard", c. 1830s.  Both examples are difficult to prepare dry mounted thin sections of teeth. The example on the left is a section of "Elephant's Grinder", and on the right, of "Walrus Tooth".  A careful comparison of the engraved handwriting to that on known examples prepared by W.H. Darker c. 1840, strongly suggests the possibility that these preparations were actually made and labeled by Darker. 

Above, four engraved slides,  all c. 1830s and labeled with Pritchard's name. The Pritchard papered slide "Larva Gnat" is standard 1" x 3" size for comparison. The leftmost slide (also shown enlarged below left) labeled "Antigua" is a thick, uncovered section of fossil palm. The 2nd and 3rd slides from left (shown enlarged above) are constructed using a thick glass base slide, while the specimen is covered with a thinner glass and sealed with red sealing wax. The 4th slide is a typical red wax sealed mount using two glass slips of equal size and thickness.

Above, four slides by C.M. Topping. The two blue and one green papered examples are early to mid 1840s, with labels showing a remarkable similarity in handwriting to the Pritchard engraved slide on the left. It is not currently known how or when Topping acquired his expert mounting skills, but based on the evidence, it seems likely that he was providing slides for retail sale by Andrew Pritchard during the 1830s.

Below, the four engraved label Pritchard slides showing variation in construction technique and glass thickness. A standard thickness papered slide is shown for comparison.

Above, a rare engraved label slide, "Arbol del Coral" ~ "Pritchard  18 Pickett". This was the earliest Pritchard shop address, from 1827 to 1839.  The engraved handwriting again looks very much like Darker's, with the slide prepared using an unusual variation of the red sealing wax construction seen on other similar slides. This is a typical dry mount of three wood sections.

Featured above, a selection of Pritchard papered mounts. Although undated, the address of 263 Strand shown on several, dates them to between 1836-1839, when Pritchard had a shop at that location. The examples bearing the 162 Fleet Street address would be dated between 1839 and 1859, with the smaller size of the two yellow papered ones suggesting the earlier dating. The small green and cream papered slide is likely an import from France for resale. The "Larva Gnat" specimen (left) is the recommended "standard" size suggested by the MSL in 1839, at 1" x 3", and shown for size comparisons.

Shown to the left (front view), and below (back view), 4 unsigned examples with printed labels that are early mounts possibly sold by Pritchard (c. 1830s). They are compared with a signed example (also shown above) for size and construction details. Careful examination of the cover papers shows a very close match, with construction nearly identical in technique. The four unsigned examples all have mica covers, while the signed "Scales House Moth" has an irregular thin glass cover.

Above, an interesting combination brass live-box with micrometer from Pritchard's 162 Fleet Street Shop, dating it to after 1839. Shown with standard 1" x 3" slide for size comparison. 

Below, two different sizes of engraved label mounts using Red Sealing Wax edge construction, with the larger at 1" x 3", and the smaller examples at 5/8" x 2".  Comparing these with images of slides labeled with engraved handwriting shown on the W.H. Darker page would suggest the strong possibility that these were also actually made by Darker.  

Above, a series of early "test" slides, all being approximately 5/8" x 2" glass with mica covers held in place with front cover papers, c. 1830s. Such early slides, made using various natural objects, were described and promoted by Pritchard and Goring as a useful test of microscope lens quality. A later version of a standard size 1" x 3" test slide from Smith, Beck & Beck is shown for size comparison.
Above, below and to the left, additional examples of various preparations constructed using two equal sized glass slides, joined together with beveled edges filled using red sealing wax. While some of these slides do have Pritchard's name printed on one side of the enclosed paper label (left), many more instead have the specimen's common name on one side with the Latin name on the reverse (see the pair of slides below). Quekett, in his 1848 book describes this technique as "Mr. Darker's Method" (see introductory comments for the link)

Shown above, two red wax mounts displaying the front and back side of each slide: "Mahogany" and a "Fern" species. Each set of images has been displayed side by side for comparison. Note the printed labeling, with the common name visible on one side of the slide, and the Latin (scientific) name on the other. It is thought by some that these slide labels would possibly have been cut from pages provided from Pritchard's book, "The Microscopic Cabinet", published in 1832.