44-1 



express the relation of this body to hydrogen, the unit of the scale. 

 For since in sulphuretted hydrogen the hydrogen is not altered in 

 hulk by the sulphur it holds in solution, the increase of weight shows 

 the proportion of sulphur combined. And so likewise in sulphurous 

 acid gas, the bulk is not greater than that of the oxygen which it 

 contains ; and since the specific gravity is double that of oxygen, the 

 increase proves that sulphur, in this instance, has combined with an 

 equal weight of oxygen. When sulphur combines with a larger pro- 

 portion of oxygen, the presence of water appears to be requisite as 

 the medium of union. In the phosphoric acid, on the contrary, water 

 is not necessary for uniting the full proportion of oxygen with which 

 phosphorus is capable of combining. 



With respect to the water that has been observed to be retained 

 by many earths, and metallic precipitates, it is remarked, that this is 

 probably combined with them in definite proportion, and that the 

 presence of the water has considerable influence on their colours, and 

 on other properties. 



On a new detonating Compound: in a Letter from Sir Humphry Davy, 

 LL.D. F.R.S. to the Right Hon. Sir Joseph Banks, Bart. K.B. 

 P.R.S. Read November 5, 1812. [Phil. Trans. 1813,^. 1.] 



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 

 fulnunating 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 endea- 

 vours to form larger quantities in a Wolfe's apparatus, by a series of 

 bottles containing the different solutions. 



