Martin’s, or Jewel, formerly Brick, Tower, was, until recently, the residence of the keeper of the jewels. It caps the north-east angle of the ward, and is in plan an irregular circle 40 feet diameter. Its base for 12 feet or 14 feet, seen in the outer ward, is solid; but, unlike the other towers, is mere rough foundation work, evidently intended to be covered up. Possibly Brass Mount, a bastion of the outer ward, just in front of this tower, was a small mound or cavalier, and extended backwards to the tower. But, however this may have been, the outer ward, at the base of this tower, was certainly 10 feet to 12 feet higher than it now is. Above the foundation, the wall of the tower, some way up the basement floor, is of fine close-jointed ashlar, like that of Bell Tower. Still higher, the wall is rubble, with vertical lines of ashlar, as described in Beauchamp Tower. The interior of this tower is so disfigured with lath-and-plaster partitions, and linings of wood, and so cut up into small domestic apartments, that little or nothing can be made of its original details, which probably remain but slightly altered. The basement floor, until recently the jewel-house, and now a kitchen, is circular, or nearly so, in plan, with three loops opening beneath pointed arch recesses. This floor has plain chamfered ribs. The entrance was at the gorge; and on the right, or south, is a well-stair; and on the left traces of a mural chamber. These, no doubt, occupied the two circular turrets shown appended to this tower in the view of 1597. The first floor is evidently original, though still more obscured than that below. This tower is probably of the reign of Henry III. The jewels seem to have been moved here soon after 1641, from the south side of the White Tower, then used as a powder-magazine, which it was feared might be endangered by the adjacent chimneys. The Crown jewels, regalia, and the public treasures were originally lodged in the New Temple. King John, however, employed the Tower as a treasury; and sent 4,000 marks thither in 1212. The Bishop of Winchester was his treasurer there in 1215. In 1218, when De Faukenberg was treasurer, money was kept both here and at the Temple. 37 Henry III. (1252–3), the royal jewels and treasure were kept at both places. But, in that year, the regalia were sent, sealed up, to the Tower; and, from this reign, the treasury was here. Thus (14 Edward III.) certain jewels are described as “En la Blaunche Tour deinz la tour de Londres.” And (18 Edward III.) are mentioned: “Claves interioris cameræ juxta aulam nigram in Turre Londˢ. ubi jocalia Regis privata reponuntur.” And (30 Edward III.) we hear of the “Tresorie deinz la haute Toure de Londres.” Long afterwards there were, perhaps, two strong places; for (20 James I.) occurs: “His Majesty’s secret Jewell house in the Tower.”—[“Kal. of the Exch.,” iii. 197, 208, 225, 424.] And such entries are numerous.