I immediately recognised in this gallery the presence of a considerable quantity of the dangerous gas called by miners firedamp, the explosion of which has often occasioned such dreadful catastrophes.

我立刻意识到这个画廊里存在着相当数量的危险气体， 矿工们称之为沼气，这种气体的爆炸经常引起如此可怕的灾难。