The present account is intended as a caution to others against the dangerous effects of the very explosive detonation, by which the author has himself been a sufferer. His attention was first directed to the subject by a letter received from France, mentioning that about twelve months since, a compound had been discovered of azote with chlorine, which appears in the form of an oil heavier than water, and which explodes, by a gentle heat, with all the violence of the fulminating metals. The letter adds, that this discovery cost the operator an eye and a finger. Since the letter contained no account of the mode of preparing the compound, and as none could be found in any of the French journals, Sir Humphry Davy pursued a hint given him by Mr. Children, who informed him that his friend Mr. Burton had, in the month of July last, observed the formation of a volatile oily substance in a solution of nitrate of ammonia, exposed to chlorine in the state of gas. In repeating the experiment, the author perceived first an oily film on the surface of the fluid, which gradually collected into small globules, and fell to the bottom. One of these globules being taken out while floating on the surface of the water, and slightly warmed, exploded with brilliant light, but with out any violence of detonation. In a series of experiments carried on jointly with Mr. Children and Mr. Warburton, other ammoniacal solutions were substituted, and it was found that the same product was obtained by means of oxalate of ammonia, or by a weak solution of pure ammonia. The first instance that occurred of violent explosion, was in their endeavours to form larger quantities in a Wolfe’s apparatus, by a series of bottles containing the different solutions.