12 Precision Measuring Instruments, c. 1870–1900

1) Kohlrausch's universal bridge, no. 1822, Hartmann & Braun, with comparative resistors from 0.1 to 1000 ohms, induction coil and slide resistor, on mahogany base. – 2) Precision plug resistor with manganese wire-winding, no. 10320, Siemens & Halske, 11 2/5 x 7 in. – 3) Ammeter, Hartmann & Braun, 100 A, walnut case, height 7 4/5 in. – 4) Mirror galvanometer by Hartmann & Braun, no. 1304, brass case, height 9 1/2 in. – 5) United ammeter and voltmeter, no. 228, Reiniger & Co, Munich, up to 150 volts and 150 amps, crack in scale glass, transportable in box. – 6) Rotary capacitor, A.W. Gamage Ltd., London, graduation in microfarads, in glass cylinder. – 7) Resistor box, J. Carpentier à Paris, no. 1094, with 4 sliding contacts. – 8) Auxiliary resistor, Otto Wolff, Berlin, with 2 cranks and 1 plug-in board for the currents of 0.1, 0.01, 0.001 and 0.0001 amperes. – 9) Rotary rheostat, J. Carpentier à Paris, circular brass case. – 10) French instrument, P. Vinay, function not known, with 4 electrical connections, height 10 ½ in. – 11) Precision plug resistor with manganese wire winding, no. 557, "Siemens Units", Latimer Clark Muirhead & Co., Westminster, brass fittings, hard-rubber plate and walnut case, with 5 plugs. – And: 12) Tangential galvanometer, Philip Harris Ltd., Birmingham, no. 20344, height 21 cm.

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)