Stanhope (optical bijou)
Encyclopedia
Stanhopes or Stanho-scopes are optical devices that enable the viewing of microphotograph
s without using a microscope. They were invented by René Dagron
in 1857. Dagron bypassed the need for an expensive microscope to view the microscopic photographs by attaching the microphotograph at the end of a modified Stanhope lens
. He called the devices bijoux photomicroscopiques or photomicroscopic jewels. In 1862, Dagron displayed the devices at the Exhibition
in London
, where he got an "Honourable Mention" and presented them to Queen Victoria. In 1864 Dagron became famous when he produced a stanhope optical viewer which enabled the viewing of a microphotograph 1 square millimetre (0.0015500031000062 sq in), (equivalent in size to the head of a pin), that included the portraits of 450 people.
invented microphotographs using a collodion
process and a microscope converted to a camera. This resulted in a microphotograph about 3 square millimetre (0.0046500093000186 sq in) in area. The main disadvantage of Dancer's method was that the viewing of the microphotographs required a microscope which was at the time an expensive instrument. In 1857 Dagron solved the problem by inventing a method of mounting the microphotographs at the end of a small cylindrical lens. Dagron modified the Stanhope lens by sectioning the normally biconvex Stanhope lens and introducing a planar section so that the plane was located at the focal length
of the convex side of the cylindrical lens. This produced a plano-convex lens, where Dagron was able to mount the microscopic photograph on the flat side of the lens using Canada balsam
as adhesive. This arrangement enabled the picture to be focused.
The stanhope optical viewers were also mounted inside the bows of violin
s by French violin maker Jean-Baptiste Vuillaume, probably using Dagron's methods and equipment. The violin stanhopes featured the portraits of famous people such as Paganini, Tourte and Stradivari.
The sectioned lens could magnify the microphotograph three hundred times, so that the viewing of the microphotographs no longer required a bulky and expensive microscope. The modified Stanhope lens was small enough to be mounted in all manner of miniature artifacts such as rings, ivory miniatures, wooden toys etc. Dagron also designed a special microphotographic camera which could produce 450 exposures approximately 2 by 2 mm (0.078740157480315 by 0.078740157480315 ) on a 4.5 centimetre wet collodion plate.
Dagron's efforts met with great success. The viewers were first introduced to the general public at the 1859 International Fair in Paris.
The success of his viewers enabled Dagron to purpose-build a factory dedicated to their production. As of June 1859, Dagron's factory was manufacturing the stanhopes, mounted in jewellery and souvenirs. In August 1859 he exhibited them at the Paris Exhibition where they met with great success. In 1862 he had 150 employees and was manufacturing 12,000 units a day.
In 1860 Dagron obtained the patent for his viewers under the title Bijoux Photomicroscopiques. Dagron also developed mail order
marketing techniques for his viewers.
In 1862 Dagron published his book Cylindres photo-microscopiques, montés et non montés sur bijoux.
In the early twentieth century Eugène Reymond took control of Dagron's stanhope lens factory in Gex
, France
. He was succeeded in the management of the factory by his son Roger. In 1972 the factory, run by Roger Remond, produced the last stanhope lens made by the traditional methods. In 1998, after Roger's death, the workshop was closed and its equipment dismantled and sold. Stanhope lenses are still manufactured to this day, but they are not produced according to Dagron's methodology.
In modern times, the most common stanhopes are usually gold or silver crosses with Christian prayers in the microphotograph.
Microform
Microforms are any forms, either films or paper, containing microreproductions of documents for transmission, storage, reading, and printing. Microform images are commonly reduced to about one twenty-fifth of the original document size...
s without using a microscope. They were invented by René Dagron
René Dagron
René Prudent Patrice Dagron was a French photographer and inventor. He was born in Aillières-Beauvoir, Sarthe, France....
in 1857. Dagron bypassed the need for an expensive microscope to view the microscopic photographs by attaching the microphotograph at the end of a modified Stanhope lens
Stanhope lens
A Stanhope lens is a simple, one-piece microscope invented by Charles, the third Earl of Stanhope. It is a cylinder of glass with each end curved outwards, one being more convex than the other. The focal length of the apparatus is at or within the device so that objects to be studied are placed...
. He called the devices bijoux photomicroscopiques or photomicroscopic jewels. In 1862, Dagron displayed the devices at the Exhibition
1862 International Exhibition
The International of 1862, or Great London Exposition, was a world's fair. It was held from 1 May to 1 November 1862, beside the gardens of the Royal Horticultural Society, South Kensington, London, England, on a site that now houses museums including the Natural History Museum and the Science...
in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
, where he got an "Honourable Mention" and presented them to Queen Victoria. In 1864 Dagron became famous when he produced a stanhope optical viewer which enabled the viewing of a microphotograph 1 square millimetre (0.0015500031000062 sq in), (equivalent in size to the head of a pin), that included the portraits of 450 people.
History
In 1851 John Benjamin DancerJohn Benjamin Dancer
John Benjamin Dancer was a scientific instrument maker and inventor of microphotography. He also pioneered stereography. By 1835, he controlled his father's instrument making business. He was responsible for various inventions, but did not patent many of his ideas. In 1852, he invented the...
invented microphotographs using a collodion
Collodion
Collodion is a flammable, syrupy solution of pyroxylin in ether and alcohol. There are two basic types; flexible and non-flexible. The flexible type is often used as a surgical dressing or to hold dressings in place. When painted on the skin, collodion dries to form a flexible cellulose film...
process and a microscope converted to a camera. This resulted in a microphotograph about 3 square millimetre (0.0046500093000186 sq in) in area. The main disadvantage of Dancer's method was that the viewing of the microphotographs required a microscope which was at the time an expensive instrument. In 1857 Dagron solved the problem by inventing a method of mounting the microphotographs at the end of a small cylindrical lens. Dagron modified the Stanhope lens by sectioning the normally biconvex Stanhope lens and introducing a planar section so that the plane was located at the focal length
Focal length
The focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated rays are brought to a focus...
of the convex side of the cylindrical lens. This produced a plano-convex lens, where Dagron was able to mount the microscopic photograph on the flat side of the lens using Canada balsam
Canada balsam
Canada balsam, also called Canada turpentine or balsam of fir, is a turpentine which is made from the resin of the balsam fir tree of boreal North America...
as adhesive. This arrangement enabled the picture to be focused.
| "If you look at the middle of the pearl eye in each nut you will see a little lens, through which you can see Paganini, Tourte and Stradivari. It’s a little joke which causes much amusement" |
| Jean-Baptiste Vuillaume |
The stanhope optical viewers were also mounted inside the bows of violin
Violin
The violin is a string instrument, usually with four strings tuned in perfect fifths. It is the smallest, highest-pitched member of the violin family of string instruments, which includes the viola and cello....
s by French violin maker Jean-Baptiste Vuillaume, probably using Dagron's methods and equipment. The violin stanhopes featured the portraits of famous people such as Paganini, Tourte and Stradivari.
The sectioned lens could magnify the microphotograph three hundred times, so that the viewing of the microphotographs no longer required a bulky and expensive microscope. The modified Stanhope lens was small enough to be mounted in all manner of miniature artifacts such as rings, ivory miniatures, wooden toys etc. Dagron also designed a special microphotographic camera which could produce 450 exposures approximately 2 by 2 mm (0.078740157480315 by 0.078740157480315 ) on a 4.5 centimetre wet collodion plate.
Dagron's efforts met with great success. The viewers were first introduced to the general public at the 1859 International Fair in Paris.
The success of his viewers enabled Dagron to purpose-build a factory dedicated to their production. As of June 1859, Dagron's factory was manufacturing the stanhopes, mounted in jewellery and souvenirs. In August 1859 he exhibited them at the Paris Exhibition where they met with great success. In 1862 he had 150 employees and was manufacturing 12,000 units a day.
In 1860 Dagron obtained the patent for his viewers under the title Bijoux Photomicroscopiques. Dagron also developed mail order
Mail order
Mail order is a term which describes the buying of goods or services by mail delivery. The buyer places an order for the desired products with the merchant through some remote method such as through a telephone call or web site. Then, the products are delivered to the customer...
marketing techniques for his viewers.
In 1862 Dagron published his book Cylindres photo-microscopiques, montés et non montés sur bijoux.
In the early twentieth century Eugène Reymond took control of Dagron's stanhope lens factory in Gex
Gex, Ain
Gex is a commune in the Ain department in eastern France.It lies from the Swiss border and from Geneva. It is a sous-préfecture of Ain.-History:...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. He was succeeded in the management of the factory by his son Roger. In 1972 the factory, run by Roger Remond, produced the last stanhope lens made by the traditional methods. In 1998, after Roger's death, the workshop was closed and its equipment dismantled and sold. Stanhope lenses are still manufactured to this day, but they are not produced according to Dagron's methodology.
In modern times, the most common stanhopes are usually gold or silver crosses with Christian prayers in the microphotograph.