Edgar is known as the origin of the
Temperance Movement in Ireland because he poured alcohol out his window in 1829. On 14 August 1829 he wrote a letter in the
Belfast Telegraph advocating
temperance. He formed the Ulster Temperance Movement. In 1834, Edgar told a parliamentary committee inquiring into the causes and consequences of drunkenness in the United Kingdom that there were 550 "dram shops" in Belfast and 1,700 shops selling intoxicants in Dublin as well as numerous illicit distillers "even in the most civilised districts of Ulster". He was also the founder of the
Ulster Female Penitentiary in 1839 which was a residential home for prostitutes; and was instrumental in getting the Deaf, Dumb and Blind Institute set up in Belfast. The meeting which led to the establishment of the Presbyterian Orphan Society was held in 1866 in his drawing room. ==Home mission and famine relief in Connaught==