These filterers are filled with bone-black, a substance resembling pulverized charcoal.

这些过滤器充满了骨黑色，一种类似于炭粉的物质。

Pipes convey it from thence into five filterers, holding several hogsheads each.

管道将其从那里输送到五个过滤器中，每个过滤器装有几个大桶。