Around 1830, the Hungarian mathematician János Bolyai and the Russian mathematician Nikolai Ivanovich Lobachevsky separately published treatises on hyperbolic geometry.

Around 1830 to 1832 Joseph Henry made a similar discovery, but did not publish his findings until later.

Around 1830 Faraday established that the reactions at each of the two electrode – electrolyte interfaces provide the " seat of emf " for the voltaic cell, that is, these reactions drive the current.

Around 1830 Abbé Michon became interested in handwriting analysis.

Around 1826, people slowly began settling on the island ; by 1830, approximately six families made up its entire population.

Around 1830, a town hall was built, and a notary public moved from nearby Oudega to Drachten.

Around 1830, dozens of windmills were erected throughout in the municipality.

Around 1670, the new French hautbois began replacing the shawm in military bands, concert music and opera ; by 1700, the shawm had all but disappeared from concert life, although as late as 1830 shawms could still be heard in German town bands performing their municipal functions ( Baines, 1991 ).

Around 1830 new civic and government buildings began to emerge in Lugano.

Around 1830, Planche was introduced by the famous writer Alfred de Vigny to François Buloz, director of the Revue des deux mondes, and contributed to this journal until 1840.

Around it is a walled graveyard, with a watchhouse built after a bodysnatching raid in 1830.

Around 1830, she was sent with her brother Daniel to live with their aunt in London.

Around 1825 both Lyell and Sedgwick had supported William Buckland's Catastrophism which postulated diluvialism to reconcile findings with the Biblical account of Noah's ark, but by 1830 evidence had shown them that the " diluvium " had come from a series of local processes.

Around 1830, small boys began to be dressed in sashed or belted tunics over trousers, a fashion which replaced the earlier skeleton suit.

Around 1830 ( though not all sources agree on the date ), he built the Benning Bridge as a toll bridge, one of the earliest crossings over the Anacostia River.

Around 1830, the Hudson's Bay Company ( HBC ), today popularly known simply as « The Bay », started the fur trade business in Nunavik by establishing their first post on the east shore of the Koksoak River, about 5 km downstream from the present-day settlement.

Around 1830, George Boole, the mathematician, taught at Waddington Academy Boarding School in the village, run by Robert Hall.

Around 1830, the Fulbe conquered the Mbum village of Delbé, which they renamed Ngaoundéré, after a nearby hill.

Around 1830 the discussion started for a renewed fortification of the Drøbak Narrows and the first stage was ready in 1848, the next in 1853.

Around 1830, he raised funds to build a synagogue in Uman to accommodate the increasingly large Rosh Hashana pilgrimage, and composed a number of prayers to be recited at Nachman's grave by his followers.

Around 1836, Hamersley decided to emigrate to Western Australia, largely on the basis of optimistic letters received from his sister Frances, who had emigrated to Western Australia with her husband William Locke Brockman in 1830.

Around 1830, the auxiliary buildings of the Abbey, in particular those that bordered on the Freyung, were renovated and partially rebuilt by Joseph Kornhäusel.

Around 1830, the English scientist Michael Faraday found that diluted nitric acid would attack steel, but concentrated nitric acid would not.

Around the same time, East Bay Ray had tried to pressure the rest of the band to sign to the major record label Polydor Records ; Biafra stated that he was prepared to leave the group if the rest of the band wanted to sign to the label, though East Bay Ray asserts that he recommended against signing with Polydor.

Around 85 percent of women who undergo FGM experience Types I and II, and 15 percent Type III, though Type III is the most common procedure in several countries, including Sudan, Somalia, and Djibouti.

Around 85 percent of women experience Types I and II, and 15 percent Type III, though Martha Nussbaum writes that Type III nevertheless accounts for 80 – 90 percent of all such procedures in countries such as Sudan, Somalia, and Dijbouti.

Around 1740 his musical output fell sharply, even though he continued fulfilling his duties as Hamburg music director.

Around 1747 he had a son by a Miss Edington, and though he gave his child James Smeaton Hutton financial assistance, he had little to do with the boy who went on to become a post-office clerk in London.

This was later shortened to "( We're Gonna ) Rock Around the Clock ", though this form is generally only used on releases of the 1954 Bill Haley Decca Records recording ; most other recordings of this song by Haley and others ( including Sonny Dae ) shorten this title further to " Rock Around the Clock ".

Around this same time Dano-Norwegian ships, joined by ships from various other European countries, began journeying to Greenland to hunt bowhead whales, though no formal recolonization was attempted.

Around this time, the cult of Adonis is noted in the Book of Ezekiel in Jerusalem, though under the Babylonian name Tammuz.

Around 1960 Schagen started to flourish again, though population was still below 5, 000.

Around the same time Tractor Supply Company opened, though, Peebles later reopened in another location in Neshannock Township in parts of the former Kmart section of the Field Club Commons plaza after Kmart reduced itself to one location in the New Castle area after it filed for chapter 11 bankruptcy in 2002, with Tuesday Morning taking up the other half.

Around the turn of the 13th century, Layamon wrote his Brut, based on Wace's 12th century Anglo-Norman epic of the same name ; Layamon's language is recognisably Middle English, though his prosody shows a strong Anglo-Saxon influence remaining.

Around 1270, de Molay went to the East ( Outremer ), though little is remembered of his activities for the next 20 years.

Around 1980, companies in Britain started to sell US equipment quite openly, as there was no law against selling or owning accessories, though being in possession of an unlicenced radio transmitter was an offence.

Around this time, Angel publicly reveals himself as a mutant after discovering that not only has his uncle, Burt Worthington ( who goes by the name of the Dazzler — though he is in no way related to Alison Blaire, a later mutant heroine and brief love interest for Warren in her own comic series who also uses the name ), murdered Warren's father, Warren Worthington, Jr., but also poisoned his mother in order to ensure his inheritance of the Worthington fortune.

Around that time, the division received its shoulder sleeve insignia, approving it by telegram, though the insignia would not be officially authorized until 1922.

Around 1970, Hanson abandoned such gut-wrenching subjects for more subtle, though no less vivid ones.

Around 442 BCE, new comic contests were officially included in the Lenaia, though plays may have been performed there earlier on an informal basis.

Around World War I, Merck systematically patented many drugs including MDMA ( ecstasy ) and several of its analogues, though no uses for them were given.

Around this time though, Wellington received news of the town's surrender ; the urgency had diminished and Beresford's expedition could proceed at a more moderate pace.

Around 1580, King John III of Sweden, who had previously ( 1556 – 63 ) been the Duke of Finland ( a royal duke ), assumed the subsidiary title Grand prince of Finland (, to the titles of the King of Sweden, first appearing is sources in 1581 ( though first used by John III 1577 ).

Most obviously, Brian Wilson used the original music tracks for both " Fun, Fun, Fun " ( which was sped up ) and " I Get Around ", both of which had elements removed to make them appear as though they were new performances.

The album sold poorly compared to his first offering, though it did include two UK Top 20 singles, " Nothing Hurts Like Love " which reached number 3, and " Wrap My Words Around You " which peaked at number 12.

Around 140, His successor Antoninus Pius ( 138-161 ) exempted Jews who circumcised their sons, though not their servants or slaves, from the decree against circumcision.