“Come forth into the light of things, let nature be your teacher.”
-William Wordsworth

Dip into any body of water and hidden treasures will emerge. Intricate and beautiful creatures, naked to the human eye but made visible by the wonders of advancing microscope technology, fascinated the Victorians who worshiped at the altar of the natural world. In an age which adored blending science and art, minute masterpieces were crafted with these specimens upon glass slides throughout England, France, Germany, and the United States. 

Most of these slides were produced from 1830-1930 using an immense variety of flora and fauna, including butterfly scales, plant parts, minerals, algae, protozoa, even slices of mummies. This wide range fed into the 19th century rage of collecting, which was prompted by the huge influx of readily available consumer goods. This meant that affordable, good quality microscopes could be found in almost every parlour. Microscopy became a popular pastime for individuals of all social classes. 

By examining who was creating these works of art and the social context they were used in, helps to illuminate the values of European society during the 19th century. This pastime demonstrates the transition from Romanticism's veneration of the beauty of nature to the Victorian's obsession with consumption and meticulous technique - tiny jewels arranged perfectly under glass. 

Joseph and Theodore Jones,  "Slide with Radiolarians", London, ca. 1863. 

The world in the 1800's was a quickly changing place, as scientific and social advances were rampant. Developments like electricity and photography, as well as social reform movements for education and health focused upon the widely touted belief that all human endevour must strive to work toward the "embetterment" of society. 

Scientific voyages to collect specimens from around the globe stimulated great advances in the understanding of the natural world, and the hunger for beautiful samples spread to the homes of microscopists who saw no conflict between technical study and aesthetic pleasure. These pursuits ennobled them in the eyes of their peers. 

The Wakefield Microscopical Society, England, March 19, 1862

In the Victorian era, the growth of the middle class, in combination with a desire to understand and categorize the natural world, fueled the spread of "parlour" microscopist clubs. Members could afford to have their own economical, effective apparatus at home, they collected and traded mounted slides voraciously and enjoyed showing off their prized specimens. England, being an island nation with expanding railways, encouraged amateur slide mounters to collect samples along the long coastlines, which combined perfectly with the country's new-fangled interest in healthy outdoor activities.

Eduard Thum, "Salon Rosette", Diatoms and Sponge Spicules arranged slide. Germany, ca. 1880.
Spicules provide structural support within most sea sponges and deter predators. 
Eduard Thum was a renowned slide preparer and is still widely collected today.

Sought by artists and scientists for the artistic shapes of their mineral skeletons, some of the most popular arranged slides were made with Diatoms, unicellular algae with glass shells of silica, which measured about 100 to 200 micrometers wide. Intricate, mysterious, mathematical and beautiful, they caused philosophers to ponder the evidence of God's hand in creation. Dating back to the Jurassic period, there are an estimated 1 million species but only about 100,000 are known today. Found in oceans, freshwater and soil, diatoms were easy to obtain in tidal pools and ditches and lent themselves to the popular educational bourgeoisie leisure activity.

Ernst Haeckel, "Plate 84 - Diatomeae", Kunstformen der Natur (Art Forms in Nature). Engraving, Germany, 1904.

Ernst Haeckel was a German biologist and artist who was inspired by the symmetry, order and organization of various organisms. He created over 1000 engravings of these observations, the best of which were published in a popular two-volume book, Kunstformen der Natur (Art Forms in Nature). A number of the most striking of his images involved Diatoms and Radiolarians, single-celled protozoans each producing unique architectural, lace-like glass skeletons, many discovered by Haeckel. These images fed the amateur microscopists' passion and desire to obtain samples of these near-invisible treasures. The humble diatom had triumphed in the world of microscopy.

Johann Deidrich Möller, "Arranged Diatoms" arranged slide, Germany, 1889 

All professional mounters prepared and sold numerous slides of material sourced from around the world. Using micro-manipulation, several elements like diatoms and radiolarians could be arranged on a permanent slide - originally in a random "strew" style, but eventually becoming more refined with individual specimens mounted singly or loosely arranged into small groups or lines. This culminated with a small number of virtuosos whose products ranged from slides of primarily scientific interest, such as grids of named species, to miniature masterpieces, often with hundreds of elements arranged into complex mandala-like patterns that could fit onto the head of a nail.

W. Watsons & Sons, "Diatoms, Butterfly Scales and Spicules", England ca. 1880's-1890's

The process to create a slide involved hours of painstaking labor. First, the specimen was thoroughly cleaned. Then, under a high-powered microscope, individual organisms were isolated and sorted, based on size and shape, sometimes using boar bristles or cat’s whiskers to manipulate them. The selected samples were placed inside a specially designed airtight box and were carefully positioned into the actual arrangement upon a 1x3 inch glass slide. This allowed the work to be created in an enclosed environment safe from passing breezes, sneezes or dust. Finally, the arrangement was permanently sealed with Canada balsam and a thin cover glass applied on top. 

A specially designed microscope (maker unknown), used for the preparation of exhibition mounts.
The airtight cabinet allowed remote manipulation and arrangement of the microscopic objects. ca. 1870.

Early paper slide covers as used by John Thomas Norman, London, ca. 1840.
The John T. Norman microscopy business was possibly the most prolific of the era and operated for 90 years.

As the demand for new and varied specimens increased, commercial mounters began to set up shop to take advantage of the intense interest in all things microscopic. The competition was so fierce that they began using colourful, branded paper to label their slides to appeal to collectors as well as to stand out in the market. Most preparers also sold equipment and accessories in their shops but by 1870, at least one mounter, W. A. Firth made most of his profits from his slides.

Microscope Slide Cabinet, ca. 1880, sold by Charles Collins, London.

Home microscopy became so popular, that specialized accessories designed to be placed in pride of place began to appear on the market. Slide cabinets (from small tabletop versions to huge floor-to-ceiling pieces), engraved ebony or ivory microscopes and other elaborate tools were sold to eager hobbyists keen to show off their collections.

W. Watson & Sons "Eggs of Butterflies, Etc." arranged slide, London, ca. 1885

Concerned that people might lose interest in single species slides arranged in rows, mounters got creative and designed new types of “salon” slides. Diatoms, spicules, butterfly scales and other minute objects were arranged in highly desirable geometric shapes. This appealed greatly to the customers eager to impress their fellow microscopists. The added benefit of this was that the price for such creations was much higher – in one instance, 15 shillings compared to ninepence for a simple mount.

Harold Dalton, for W. Watson & Sons, "Flowers, Grasses, Ferns, Insects, and Birds", London, ca. 1880s. Exhibition or Picture Mounts made using butterfly and insect wing scales, etc.

Exhibition slides were an enhanced variation of the arranged mount. Incredibly elaborate and detailed images were produced by positioning hundreds or even thousands of individual objects within the design. The best examples were produced by Harold Dalton under the W. Watson & Sons of London label. Birds, flowers and insects were reproduced in miniature with painstaking precision manipulating elements with microns of movement. This was the pinnacle of the slide mounters craft.

Although arranged microscope slides were readily available throughout Europe and North America during the Victorian era, today, this has become an almost lost art. A handful of practitioners keep the tradition alive, but for most, the existence of these tiny jewels is unknown and a wonderous discovery. Klaus Kemp is one of these modern day slide preparers. His story is told simply and beautifully by Matthew Killip's short film, The Diatomist.