The centrolinead was invented by
Peter Nicholson, a British
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
and
architect
An architect is a person who plans, designs and oversees the construction of buildings. To practice architecture means to provide services in connection with the design of buildings and the space within the site surrounding the buildings that h ...
, in 1814.
It was used to construct
2-point perspective drawings
Drawing is a form of Visual arts, visual art in which an artist uses instruments to mark paper or other two-dimensional surface. Drawing instruments include graphite pencils, pen and ink, various kinds of paints, inked brushes, colored pencils, ...
where one or both
vanishing points existed outside the drawing board.
Draftsmen
A drafter (also draughtsman / draughtswoman in British and Commonwealth English, draftsman / draftswoman or drafting technician in American and Canadian English) is an engineering technician who makes detailed technical drawings or plans for ...
could use the instrument in pairs; one for each vanishing point on each side of the
station point.
Centrolineads were produced in various sizes. Typically a
brass
Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different mechanical, electrical, and chemical properties. It is a substitutional alloy: atoms of the two constituents may replace each other with ...
fitting clamped the
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...
en arms together. Fittings were produced in both right and left-handed configuration, and certain adjustable designs could be used on either side.
Usage
Two short arms are set to form 90 degree angles against a third, longer drawing edge.
Pins
A pin is a device used for fastening objects or material together.
Pin or PIN may also refer to:
Computers and technology
* Personal identification number (PIN), to access a secured system
** PIN pad, a PIN entry device
* PIN, a former Dutch de ...
are placed near the edges of the drawing surface and serve as pivots for the arms. Pin placement is equidistant and symmetric across the
horizontal line. A third centrolinead could be used to construct
3-point perspective.
The diagram shown above does not represent the centrolinead designed by Nicholson.
Further reading
* Centrolineads and their use are discussed in
W.F. Stanley's book on mathematical instruments.
*{{cite book, last1=Davy, first1=Sir Humphry, last2=Survey, first2=U. S. Coast and Geodetic, title=The collected works of Sir Humphry Davy ...: Discourses delivered before the Royal society. Elements of agricultural chemistry, pt. I, year=1898, publisher=Smith, Elder and Company, url=https://books.google.com/books?id=jYlNAAAAYAAJ&dq=Centrolinead&pg=PA727, pages=725–728, language=en
References
External links
Yahoo! Groups
Technical drawing tools