Question: What nationality was the author of the book Horologium Oscillatorium?
Context: The Italian, or the Confessional of the Black Penitents (1797) is a Gothic novel written by the English author Ann Radcliffe.  It is the last book Radcliffe published during her lifetime (she would go on to write the novel "Gaston de Blondeville", which was published posthumously in 1826).  "The Italian" has a dark, mysterious and somber tone, and concerns the themes of love, devotion and persecution by the Holy Inquisition.  The novel also deals with issues prevalent at the time of the French Revolution, such as religion, aristocracy, and nationality.  Radcliffe's renowned use of veiled imagery is considered to have reached its height of sophistication and complexity in "The Italian"; concealment and disguise are central motifs of the novel.  In line with late 18th-century sensibility and its parallel fetishisation of the sublime and the sentimentally pastoral, the heightened emotional states of Radcliffe's characters are often reflected through the pathetic fallacy.  The novel is noted for its extremely effective antagonist, Father Schedoni. Dr. Nyla Ali Khan is a Visiting Professor at the University of Oklahoma and former professor at the University of Nebraska-Kearney.  She is the author of two books, including "The Fiction of Nationality in an Era of Transnationalism" and "Islam, Women, and Violence in Kashmir: Between Indian and Pakistan," and several articles that focus heavily on the political issues and strife of her homeland, Jammu and Kashmir, India.  Despite being the granddaughter of Sheikh Abdullah, Nyla Khan prefers not simply to live in his shadow but to "stand up for myself and be taken seriously ... express my anger without being labeled an 'Islamic militant' ... [and] legitimately question things I don't understand", as she stated in a 2010 interview related to the release of her second book. Christiaan Huygens, FRS ( or ; ] ) (Latin: "Hugenius" ) (14 April 1629 – 8 July 1695) was a prominent Dutch mathematician and scientist.  He is known particularly as an astronomer, physicist, probabilist and horologist. Jean Graton (born 10 August 1923) is a comic book author and cartoonist of French nationality.  Graton created the famous character Michel Vaillant and the eponymous series in 1957. A conical pendulum consists of a weight (or bob) fixed on the end of a string or rod suspended from a pivot.  Its construction is similar to an ordinary pendulum; however, instead of swinging back and forth, the bob of a conical pendulum moves at a constant speed in a circle with the string (or rod) tracing out a cone.  The conical pendulum was first studied by the English scientist Robert Hooke around 1660 as a model for the orbital motion of planets.  In 1673 Dutch scientist Christiaan Huygens calculated its period, using his new concept of centrifugal force in his book "Horologium Oscillatorium".  Later it was used as the timekeeping element in a few mechanical clocks and other clockwork timing devices. Horologium Oscillatorium: sive de motu pendulorum ad horologia aptato demonstrationes geometricae (Latin for "The Pendulum Clock: or geometrical demonstrations concerning the motion of pendula as applied to clocks"), often abbreviated Horologium Oscillatorium, is a book published by Christiaan Huygens in 1673; it is his major work on pendulums and horology.  This work is regarded as one of the three most important work done in mechanics in the 17th century, the other two being Galileo Galilei’s "Discourses and Mathematical Demonstrations Relating to Two New Sciences" (1638) and Isaac Newton’s "Philosophiæ Naturalis Principia Mathematica" (1687).
Answer: Dutch