later. April–June April 7–8 – Battle of Monte Santiago: A squadron of the Brazilian Imperial Navy defeats Argentine vessels in a major naval engagement. April 10 – UK: George Canning succeeds Lord Liverpool as British Prime Minister. April 23 – John Galt founded the town of Guelph, Upper Canada. April 24 – Greek War of Independence – Battle of Phaleron: Ottoman troops defeat the Greek rebels. April 26–May 24 – The Royal Netherlands Navy's British-built paddle steamer Curaçao makes the first transatlantic crossing by steam, from Hellevoetsluis to Paramaribo. April 29 – The Fly Whisk Incident in Ottoman Algeria: Hussein Dey slaps French consul Pierre Deval on the face, eventually leading to the Invasion of Algiers in 1830. May 1 – Georg Ohm published the famous book Die galvanische Kette, mathematisch bearbeitet (tr., The Galvanic Circuit Investigated Mathematically). In which the Ohm law appeared for the very first time. May 20–July 9 – Zarafa, a giraffe presented by the Ottoman Viceroy of Egypt, Mehmet Ali Pasha, to King Charles X of France, the first to be seen in Europe for over three centuries, walks from Marseille to Paris. May 21 – The Maryland Democratic Party is founded by supporters of Andrew Jackson in Baltimore, and hosts its first meeting at the Baltimore Atheneum. May 25 – Romanian inventor Petrache Poenaru receives a French patent, for the invention of the first fountain pen with a replaceable ink cartridge. June 4 – French inventor Joseph Niépce sends a package to Louis Daguerre, revealing the existence of his invention, "heliography", where an image can be reproduced onto a pewter plate and then reprinted. In 1829, the two will begin a partnership, and Daguerre will perfect Niépce's photographic process to reproduce images more quickly. June 7 – Greek defenders in Athens surrender to Egyptian forces, under the command of General Rashid Pasha. July–September July 6 – Greek War of Independence: The Treaty of London between France, Britain, and Russia, demands that the Turks agree to an armistice in Greece. July 14 – The Roman Catholic Diocese of Honolulu is founded in the Kingdom of Hawaii. August 31 – UK: Frederick John Robinson, 1st Viscount Goderich, becomes Prime Minister of the UK, following the death of George Canning. September 4 – Finland: The Great Fire of Turku destroys three-quarters of the city, with 27 human casualties. September 20 – A petition for a land grant