This deception, at present, is performed much better.

The juggler rolls together some flax or hemp, so as to form a ball about the size of a walnut; sets it on fire; and suffers it to burn until it is nearly consumed; he then rolls round it, while burning, some more flax; and by these means the fire may be retained in it for a long time.

When he wishes to exhibit he slips the ball unperceived into his mouth, and breathes through it; which again revives the fire, so that a number of weak sparks proceed from it; and the performer sustains no hurt, provided he inspire the air not through the mouth, but the nostrils.
By this art the Rabbi Bar-Cocheba, in the reign of the Emperor Hadrian, made the credulous Jews believe that he was the hoped-for Messiah; and two centuries after, the Emperor Constantius was thrown into great terror when Valentinian informed him that he had seen one of the body-guards breathing out fire and flames in the evening.
Since Beckmann wrote, the method of producing smoke and sparks from the mouth has been still further improved.

The fire can now be produced in various ways.

One way is by the use of a piece of thick cotton string which has been soaked in a solution of nitre and then thoroughly dried.
This string, when once lighted, burns very slowly and a piece one inch long is sufficient for the purpose.