See Dictamus, Botany Index.

It is remarkable of this odorous plant, that, when in full blossom, the air which surrounds it in a still night may be inflamed by the approach of a lighted candle. Dr Watton doubts whether this inflammability proceeds from an inflammable air which is exhaled by the plant, or from some of the finer parts of the essential oil of the plant being dissolved in the common atmospherical air. The latter is the most probable supposition; for were it the pure inflammable air, as Mr Cavallo observes, it would, on account of its small specific gravity, leave the plant as soon as it was produced. Common air acquires the property of becoming inflammable, by being transmitted through several essential oils.