Captain John C. Frémont, leading a U.S.…

Augustus Charles Gregory, an English-born surveyor who had migrated with his parents to Western Australia in 1829, explores the region north of Perth in 1846 with two brothers.

Jews from Galicia begin to dominate trade, crafts, and money lending in the Ottoman principalities of Moldavia and Wallachia, where a native-Romanian bourgeoisie is virtually nonexistent.

The boyars, using Jews as middlemen, grow rich through the Black Sea wheat trade, but the peasants reap few benefits.

Construction of the first major roadways, beginning in the 1840s, links the principalities, and in 1846, the Paris-educated Gheorghe Bibescu, prince of Wallachia since 1842, agrees with ...

...Moldavia's Prince Mihail Sturdza to dismantle customs barriers between the principalities, marking the first concrete move toward unification.

The Dhofar, governed by Mohammad ibn-Agil al-Ajaibi in the early nineteenth century, remains culturally and politically linked to South Arabia until the 1840s, when the region is absorbed into the Al Bu Sa'id Omani state.

Ulrich Ochsenbein champions the revision of the cantonal constitution (1846) at Bern, and heads the department of the Sonderbund's army.

Ascanio Sobrero formulates nitroglycerin while working at the University of Torino in 1846 under Théophile-Jules Pelouze, who had worked with the explosive material guncotton.

He initially calls his discovery "pyroglycerin", and warns vigorously against its use in his private letters and in a journal article, stating that it is extremely dangerous and impossible to handle.

A crop failure in France in 1846 quickly develops into a full-scale economic crisis, as food becomes scarce and expensive.

Many businesses go bankrupt, and unemployment soars.

Within the French governing elite itself there are signs of a moral crisis: scandals that implicate some high officials of the regime and growing dissension among the Notables.

Along with this goes a serious alienation of many intellectuals.

Novelists such as Victor Hugo, George Sand, and Eugène Sue glorify the common man; historians such as Jules Michelet and Alphonse de Lamartine write with romantic passion about the heroic episodes of the Great Revolution; and the caricaturist Honoré Daumier exposes the foibles of the nation's leaders.

Alexandre Dumas, responding to the immense success of The Three Musketeers, produces a sequel, Twenty Years After, in 1846.

The partial crop failure of 1845 in Ireland is followed by more devastating failure in 1846.

The British government's efforts to relieve the famine are inadequate.

Prime Minister Sir Robert Peel had done what he could to provide relief in 1845 and early 1846, but under the Liberal cabinet of Lord John Russell, which assumes power in June 1846, the emphasis shifts to reliance on Irish resources and the free market, which makes disaster inevitable.

After Daniel O'Connell advises against the use of force, O'Brien leads the Young Irelanders in withdrawing from the National Repeal Association on July 27, 1846.