有些铜大缸上一道道刮痕，是八国联军侵略中国是把上面的金刮走留下的。 紫禁城内的宫殿周围，陈列着无数引人注目的“吉祥缸”（也称“太平缸”）。“吉祥缸”有铜缸和铁缸两种，还在铜缸外包上一层棉外套，另外，在特别寒冷的季节里，要把缸架在特制的石圈上，在石圈内点燃炭火，昼夜不熄，使缸内不冻，直到大地回春。
The scratches on some copper cylinders were scratched by the Allied Forces of Eight Countries when they invaded China. Around the palaces in the Forbidden City, there are numerous noticeable "auspicious cylinders" (also known as "Taiping cylinders"). "Auspicious cylinder" has two kinds of copper cylinder and iron cylinder, and a layer of cotton jacket outside the copper cylinder. In addition, in the special cold season, the cylinder should be built on a special stone circle, ignite charcoal fire in the stone circle, day and night, so that the cylinder does not freeze until the earth returns to spring.