The Opal View, 1851

A viewing device made of thin, transparent porcelain for four rotating, colored engravings. The 90-degree angles between the images, when viewed through the 22 mm magnifying lens, create a sharp, three-dimensional illusion. The first image bears the inscription: "The Opal Views are Manufactured by J.J. Mathewson, Nos. 4, 21, 51 & 59 Thames Tunnel and will always preserve their color in any climate". It shows two superimposed colored engravings: Above, a paddle steamer on the Thames; below, the double Thames Tunnel, each with three levels. The three other engravings, with their detailed, surrounding titles, are: "Interior of the Crystal Palace Opened by Her Majesty, May 1st, 1851", "Thames Tunnel (1200 feet long, 76 feet high, water mark was 8 years building and cost ? 446,000. Opened the 25th day of March 1843)" and "The Thames Tunnel took 50,000 bricks per foot, 6,600,000 in all without the shaft, cost ? 446,000.". The device is 13 cm high, with a maximum diameter (for the engravings) of 67 mm. An original cardboard insert is glued to the base. The device bears a certain resemblance to an alabaster peep-egg, but appears much earlier and more elaborate. According to the description, Mathewson had four shops in what was then the eighth wonder of the world and sold souvenirs to visitors who admired technology. Our research indicates that it is not currently known from the literature.

布雷克拍品等级是为了方便竞买人判断拍卖品的成色而设置的。布雷克等级用1到6级来标注外观和功能的成色，(从非常好到非常差)。 在目录图册里用括号里的2个数字来表示，前一个数字表示外观成色的级别，后一个数字表示功能成色的级别。如(3/2)表示外观成色是3(满意的)，功能成色2(好)。 成色 定义参照下列标准： 1 - 非常好 (未使用过，没有使用痕迹) 2 - 好 (新，极少的使用痕迹) 3 - 满意的 (普通的使用痕迹) 4 - 及格的 (明显的使用痕迹，某个非主要部件是后配的) 5 - 有缺陷的 (极明显的使用痕迹, 某个主要部件是后配的，功能上有缺陷，需要修理) 6 - 非常差 (严重破损, 缺少重要部件)