_Turrets_.--Towers of great height in proportion to their diameter are so called. Large towers have often turrets at their corners; often one larger than the other, containing a staircase; and sometimes they have only that one. BRITISH STYLES OF ARCHITECTURE, AND THEIR DURATION. _The Norman_--Commenced before the conquest, and continued until the reign of Henry II. A.D., 1189. It is characterized by semicircular, and sometimes pointed, arches, rudely ornamented. _Early English_.--This style lasted until the reign of Edward I., A.D. 1307. Its characteristics are, pointed arches, long narrow windows, and the jagged or toothed ornament. _Decorated English_--Lasted to the end of Edward III., A.D. 1377. It is characterized by large windows with pointed arches divided into many lights by mullions. The tracery of this style is in flowing lines, forming figures. It has many ornaments, light and delicately wrought. _Perpendicular English_.--This last style employed latterly only in additions, was in use, though much debased, even as late as 1630-40. The latest whole building in it, is not later than Henry VIII. Its characteristics are the mullions of the windows, and ornamental panelings, run in perpendicular lines; and many buildings in this style are so crowded with ornament, that the beauty of the style is destroyed. The carvings of it are delicately executed. M.L.B. * * * * * THE NOVELIST. * * * * * ABAD AND ADA. _A lost leaf from the Arabian Nights_. (_For the Mirror_.) In the days of Caliph Haroun Alraschid, the neighbourhood of Bagdad was infested by a clan of banditti, known by the name of the "Ranger Band." Their rendezvous was known to be the forests and mountains; but their immediate retreat was a mystery time had not divulged. That they were valiant, the intrepidity with which they attacked in the glare of noonday would demonstrate; that they were numerous, the many robberies carried on in the different parts of the Caliph's dominions would indicate; and that they were bloody, their invariable practice of killing their victim before they plundered him would argue. They had sworn by their Prophet never to betray one another, and by the Angel of Death to shed their blood in each other's defence. No wonder, then, that they were so difficult to be captured; and when taken, no tortures or promises of reward could extract from them any information as to the retreat of their comrades. One day, as Giafar, the Vizier, and favourite of the Caliph, was walking alone in a public garden of the city, a stranger appeared, who, after prostrating himself before the second man in the empire, addressed him in these words: "High and mighty Vizier of Alraschid, Lord of the realms of Alla upon earth, whose delegate and vicegerent he is, hear the humblest of the sons of men--Vizier, hear me!" "Speak, son," said the Vizier, "I am patient."