As is well known, the Emerald Isle--so called from the luxuriance of vegetation induced by a mild and moist climate--is one of the four divisions of Great Britain, England, Wales, and Scotland being the others. It is separated from England by the Irish Sea and St. George's Channel, and contains an area of 32,531 square miles. This is not far from the size of the State of Maine, which contains 35,000. Ireland is divided into four provinces, Leinster, Munster, Ulster, and Connaught, and these comprise thirty-two counties. Its greatest population was in 1841, when it amounted to 8,199,853. During the next ten years, owing to famine and emigration, it decreased 1,600,000, that is to 6,599,853; and this was about 200,000 less than in 1821, when the first census was taken. The number of inhabited houses in 1861 was 995,156; in ten years they decreased to 960,352. The average number of persons to a house was seven, giving for 1871 a population of 6,722,464. This is not far from the present population, which is more than ten times that of the State of Maine, 626,915, and twice that of all New England, 3,487,924. As New England has 68,460 miles of surface, and Ireland 32,531, it follows that the latter has about four times as many persons to the square mile as the former. Ireland has ninety-two harbors and sixty-two lighthouses. There are in all 2,830,000 acres of bog land that is available for fuel, or about one seventh of all the island. At Dublin the mean temperature for the year is fifty degrees, which is seven degrees warmer than the average of Boston; and there is an average of but three degrees of difference between the extreme northern and southern parts. There is a perpetual moisture, which induces vegetation and maintains unfailing pasturage. This is due to the prevalence of westerly winds, which bring with them the warm moist atmosphere of the Gulf Stream. The average rainfall is thirty-six inches, or about six inches less than at Boston. Ireland boasts of great antiquity. We will, however, speak of it only from the time of St. Patrick, who was sent here by Germanus of Rome, to convert the people to Christianity. He arrived about the middle of the fifth century, and died in 493, leaving the island nominally Christian. Schools and monasteries were established; and so noted did the country become for the learning and piety of its ecclesiastics, that it was called _Insula Sanctorum_, Isle of Saints. In the year 646 many Anglo Saxons settled on the island, and in 684 it had become of sufficient importance to be invaded by Egfrid, king of Northumberland, who destroyed churches and monasteries. From this time invasions were common. In 1002 Brian Boru, who was king of the province of Munster, was powerful enough to expel the Danes who had come in, and was crowned at Tara, "King of all Ireland." Hence Moore's poem, "The Harp that once through Tara's Halls."