An erygmascope is a late 19th-century

electric Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

lighting Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. ...

apparatus designed for the examination of the

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

of earth traversed by boring apparatus. It consisted of a very powerful

incandescent lamp An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a filament until it glows. The filament is enclosed in a glass bulb that is eith ...

enclosed in a metallic cylinder. One of the two semi-cylindrical sides constitutes the reflector, and the other, which is of thick

glass Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...

, allows the passage of light, which illuminates the strata of earth traversed by the instrument. The base, which is inclined at an angle of 45°, is an elliptical

mirror A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera ...

, and the top, of straight section, is open in order to permit the observer standing at the mouth of the well, and provided with a powerful spyglass, to see in the

the image of the geological layers or of the structure of crystalline rocks. It somewhat resembles to a kind of inverted semi-

periscope A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with ...

aimed to look at earth downwards. The lamp is so mounted that its upwardly emitted rays are intercepted. The whole apparatus was suspended from a long cable, formed of two

conducting Conducting is the art of directing a musical performance, such as an orchestral or Choir, choral concert. It has been defined as "the art of directing the simultaneous performance of several players or singers by the use of gesture." The primary d ...

wires, which winds around a windlass with metallic journals which are electrically insulated. These journals communicate, through the intermedium of two friction springs, with the conductors on the one hand and, on the other, with the

poles Pole or poles may refer to: People *Poles (people), another term for Polish people, from the country of Poland * Pole (surname), including a list of people with the name * Pole (musician) (Stefan Betke, born 1967), German electronic music artist ...

of a portable battery. This permits of lowering and raising the apparatus at will, without derangement, and without its being necessary to interrupt the light and the observation. The erygmascope was described in an 1891 edition of the

Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it, with more than 150 Nobel Pri ...

Supplement; To what extent it was put to practical use is unknown.

Etymology

The

etymology Etymology ( ) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. ...

of the term remains enigmatic, but could originate from a Greek word ''ήρυγμα'' meaning "trench". However, a shaft should be translated in Greek as ''πηγάδι'' (pegadi), and a

water well A well is an excavation or structure created on the earth by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...

as ''φρέαρ'' (phrear). The origin of the suffix ''scope'' is classical for an

optical instrument An optical instrument is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common examples include periscopes, microscopes, telescopes, and camera ...

: from ''σκοπεῖν'' (skopein), meaning to look at.

In art and popular culture

Sonic and visual artistic collaboration between Tracy Hill, artist, Ralph Hoyte, poet and writer, and Phill Phelps, musician, working in partnership with Lancashire Wildlife Trust and City of Trees. It symbolizes the curiosity of the three artists for looking beyond the surface whilst working on their opus ''Stratum''.Hill, T., Hoyte, R., & Phelps, P. (2020). Erygmascope.
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References

External links

* Boreholes Historical geology Optical devices Optical instruments Scientific equipment Stratigraphy Well logging {{stratigraphy-stub

Etymology

In art and popular culture

See also

References

External links