They inhaled toxic dust and vapours as the material seethed in primitive cauldrons to extract the mercury .
当原材料被放入原始的煮锅烧沸以提炼水银时他们吸入有毒的粉尘和蒸汽。
Even more remarkably , the drop was steepest in america 's big cities which are still popularly believed to be cauldrons of criminality .
更加值得注意的是，虽然美国大城市仍被普遍认为是犯罪的温床，但那里的犯罪率下降却最为明显。
Numbers like these worry the governing communist party , which has a particular aversion to the specter of urban slums and their potential as cauldrons for social instability .
