Sometime during 1850, a London banker named W. Peters invented a device capable of microscopic writing or engraving on glass and metal. It was originally conceived of as a way to secretly mark engraving plates so as to quickly identify counterfeit  currency, but generated little interest.  Instead it was put to use writing in miniature on glass slides, by Peters and a few friends. There are a relatively few slides that were produced during that early period using the Peters Machine. Most were made by R. J. Farrants, a well known London surgeon and microscopist, and later president of the Royal Microscopical Society. These slides usually carry short phrases and maxims, although sets of ruled lines are also known to have been made.

These unusual engraved slides became more popular during the International Exhibition of 1862 when W. Webb first introduced and demonstrated his new engraving machine, and continued to produce and sell his slides commercially until at least the mid 1880s. These slides are usually of short religious texts such as the Lord's Prayer, or well known phrases, and occasionally, geometric figures. A number of individuals also made and offered slides with ruled lines engraved at so many lines per inch or millimeter, to be used as stage micrometers. Very finely ruled slides were produced by a few individuals (F.A. Nobert probably being the best known) and were used to test the resolving power of objective lens systems. Also quite rare, are examples of intricate geometric scroll patterns engraved on glass slides by W. Teasdale, using a pendulum vibrating in a compound manner, an instrument of his own design and construction.  Images below are from the slides shown.

 R. J. Farrants with the "Peters Machine"

Above, the earliest known engraved slide made with the "Peters Machine", by W. Peters himself, and dated Feb. 1851. Very few slides by Peters are known.  Below, a fine example of the more well known slides created by R.J. Farrants, also using the "Peters Machine", this one, "Why has not man a microscopic eye?" is dated Mar. 10, 1854.

 Detail of R.J. Farrants slide "The Lords Prayer", as seen top left. This is an unusual Farrants slide as it is unpapered, with descriptive details engraved directly on the slide surface.

Above, a selection of engraved slides by R.J. Farrants using the "Peters Machine", showing some of the cover paper designs he used. Below, a slide series of progressively finer ruled lines.

Diamond engraved slides by W. Webb, c. 1860s -70s. The "Lord's Prayer" slide (far left) is illustrated below with another engraving from the 1862 International Exhibition.  As well as direct sales, Webb also supplied a number of retail agents, such as E. Wheeler
W. Webb's  Announcement & Catalogue from International Exhibition, 1862


Above left, Washington Teasdale with his harmonic pendulum engraving machine, c. 1880. He used this device, which he designed and built, to create these intricate and beautiful curvilinear patterned engravings on standard 1" x 3" glass slides (above & below). Each design was a unique creation, as can be seen in the 5 patterns pictured. Imaged using Darkfield techniques.

A detail showing close-up of engraved lines made by the Teasdale Machine.

A selection of slides provided by various makers (English, Australian, & American) containing engraved ruled lines. Many of these are used for stage Micrometers, and ruled in various fractions of the Inch and the Millimeter. They allow measurement of specimens by comparison to the ruled lines of a known dimension. Another type of engraved slide used much finer gradations for testing and comparison of objective resolution.