Edward Delaval

Edward Hussey Delaval (* 1729 , † August 14, 1814 in Westminster , London) was an English chemist and experimental physicist.

life and work

Youth and education

Edward Delaval came from a family of the Northumberland nobles . Unlike his brothers, who were best known for their dissolute lifestyle, Edward developed an interest in science from an early age. After completing his master's degree in Cambridge, he became a Fellow of the local Pembroke College . In 1759 he was - supported by Benjamin Franklin - a member of the London Royal Society .

Research on electricity and lightning rods

Even before his admission to the Royal Society, Delaval had carried out physical experiments on electricity and corresponded with Benjamin Wilson in this context . Two years later appeared in the Philosophical Transactions , the publication organ of the society, under the title An Account of Several Experiments in Electricity ("Report on some experiments on electricity") another report on his research in this area. In 1764 Delaval reported in the Philosophical Transactions about the consequences of a lightning strike in the tower of St. Bride's Church in London's Fleet Street .

During Benjamin Franklin's second stay in England from 1764 to 1775, Delaval and Franklin, together with other members of the Royal Society, were appointed to a commission to work out a proposal to secure London's St Paul's Cathedral against lightning strikes. The committee members published their results in 1769 under the title Proposal of a Method for Securing the Cathedral of St. Paul's from Damage by Lightning ("Proposal of a method to protect St Paul's Cathedral from lightning damage"). Shortly after the report was finalized, the steeple was indeed struck by lightning and Delaval re-presented his views on the subject. This sparked controversy over whether the ends of lightning rods needed to be pointed or rounded to have the greatest effect achieve. Against Franklin's position, Delaval spoke out in favor of rounded ends.

Chemical experiments

As a chemist, Delaval carried out extensive experiments on glass coloring in 1755 by adding various metals. His essay published in connection with this was awarded the Gold Medal of the Royal Society. In 1775 he carried out a series of experiments on the luminous properties of phosphorus , this time together with Benjamin Wilson .

While Delaval's attempts to manufacture artificial jewels are of less importance, he experienced one with the publication of his work An experimental inquiry into the cause of the permanent colors of opaque bodies in 1777 ("Experimental investigation of the causes for permanent colors of opaque bodies") big success. The work was translated into French a year after it was first published and into Italian a year later. A second edition appeared in England in 1785, and a German translation in 1788.

Delaval's interest in glass also had an impact outside the scientific field. He owned a large collection of water-tuned glasses for making music and, during one of his concerts in 1761, inspired Benjamin Franklin to invent the glass harmonica .

Academician and past years

In addition to his membership in the Royal Society, Delaval was also a member of the Scientific Societies in Göttingen , Uppsala and Bologna. When he inherited the Delaval family after his brother's death, he preferred to stay in London. He received honorary membership for a foundation to the Newcastle Society of Antiquaries , but never returned to his native Northumberland until his death . On August 14, 1814, Delaval died as the last representative of his family at the age of 85.

Fonts

Standalone fonts

• An experimental inquiry into the cause of the permanent colors of opaque bodies , London 1777, 2nd edition Warrington 1785; French-language edition under the title Recherches expérimentales sur la cause des changemens de couleurs dans les corps opaques et naturellement colorés, ouvrage traduit de l'anglois… par M. Quatremère Dijonval… , Paris 1778; Italian-language edition under the title Ricerche sperimentali sopra le cause de 'cambiamenti de' colori nelli corpi opachi, e colorati: con una prefazione istorica; relativa alle parti di Filosofia in essa esaminate, ed alle diverse Arti, e Manifatture da quella dipendenti , Bologna 1779; German-language edition under the title Experiments and Comments on the Cause of the Permanent Colors of Opaque Bodies ... Translated from English; along with a preface by Dr. Lorenz Crell ... , Berlin and Stettin 1788.

Journal articles (selection)

• An Account of Several Experiments in Electricity: In a Letter to Mr. Benjamin Wilson, FRS By Edward Delaval, Esq; FRS , in: Philosophical Transactions 52 (1761), pp. 353-359.
• An Account of the Effects of Lightning at St. Bride's Church, Fleet-Street, on the 18th of June 1764: In a Letter to Mr. Benjamin Wilson, FRS from Edward Delaval Esq; FRS , in: Philosophical Transactions 54 (1764), pp. 227–234, available online as a PDF document in the central media directory Wikimedia Commons .
• A Letter to the Right Honorable the Earl of Morton, President of the Royal Society. Containing Experiments and Observations on the Agreement between the Specific Gravities of the Several Metals, and Their Colors When United to Glass, as Well as Those of Their Other Proportions: By Edward Delaval, FRSMA and Fellow of Pembroke Hall, Cambridge , in: Philosophical Transactions 55 (1765), pp. 10-38 (reprinted later as part of An experimental inquiry into the cause of the changes of colors in opaque and colored bodies ).
• Proposal of a Method for Securing the Cathedral of St. Paul's from Damage by Lightning; In Consequence of a Letter from the Dean and Chapter of St. Paul's to James West, Esquire, Pr. RS , in: Philosophical Transactions 59 (1769), pp. 160–169 (together with William Watson , Benjamin Franklin , Benjamin Wilson , and John Canton proposed to secure London's St Paul's Cathedral against lightning).

literature

• Francis Askham (pseud. For Julia Eileen Courtney Greenwood): The Gay Delavals. An account of the Delaval family in the eighteenth century , London 1955 (contains illustrations, portraits and a bibliography).
• Roger Burgess: Those Delavals! , Newcastle upon Tyne 1972 (book to accompany a BBC television production ).
• Richard Welford: Edward Hussey Delaval. The Last of the Delaval Race , in: Men of Mark 'twixt Tyne and Tweed, London 1895, pp. 99-102.

Remarks

1. ^ Benjamin Wilson: A Letter from Mr. Benjamin Wilson, FRS to the Rev. Tho. Birch, DD Secret. RS [Relating] a letter from Edward Delaval, MA and Fellow of Pembroke-Hall Cambridge, to Mr. Benjamin Wilson, FRS Containing Some Electrical Experiments and Observations , in: Philosophical Transactions 51 (1759), pp. 83-88.