Okay, here's a summary of significant events in 1840, formatted as a Wikipedia article entry:
1840
1840 was a leap year starting on Wednesday of the Gregorian calendar and a leap year starting on Monday of the Julian calendar.
Politics and Government
United States Presidential Election:William Henry Harrison of the Whig Party defeated incumbent Martin Van Buren. This marked a significant shift in American politics, ending the era of Jacksonian Democracy.
Treaty of Waitangi (New Zealand): This treaty was signed between representatives of the British Crown and various Māori chiefs of the North Island of New Zealand on 6 February 1840. It established British governance in New Zealand.
Act of Union 1840 (Canada): The Act of Union came into effect, uniting Upper and Lower Canada into the Province of Canada. This was an attempt to assimilate the French-speaking population and streamline governance.
Abolition Debates: Anti-slavery sentiment continued to grow internationally. Debates surrounding abolition were particularly heated in the United States and Great Britain.
Penny Postage (Great Britain): The Uniform Penny Post was introduced in Great Britain, revolutionizing communication by making postage affordable for a larger segment of the population.
Science and Technology
Goldbach's Conjecture: Christian Goldbach's famous conjecture that every even integer greater than 2 can be expressed as the sum of two primes was formulated. This remains an unsolved problem in mathematics.
Photography Advances: Continued experimentation with photographic processes led to improvements in image quality and clarity. Photography was becoming more accessible and practical.
Artificial Fertilizer: Justus von Liebig published Organic Chemistry in its Applications to Agriculture and Physiology, which revolutionized agriculture with its insights into the role of inorganic fertilizers.
Culture
Music:La Fille du régiment, an opera by Gaetano Donizetti, premiered in Paris.
Literature: Richard Henry Dana Jr. published Two Years Before the Mast, a memoir of his experiences as a sailor, offering a vivid portrayal of maritime life.
Arts: Increased prevalence of Romanticism in art and literature.
Charles Dickens' The Old Curiosity Shop: The publication of this novel contributed to Dickens' growing popularity as a social commentator and literary figure.
Other Notable Events
Hong Kong occupied: British forces occupied Hong Kong during the First Opium War.
First Adventist camp meeting: The first Adventist camp meeting was held in East Kingston, New Hampshire.