4-42 



The heat generated by the union of ammoniacal vapour and chlo- 

 rine, caused the destruction of the whole apparatus by an instanta- 

 neous explosion. 



From this time their attempts to form the oil were confined to 

 small phials of the gas, and their trials of its properties were limited 

 to a quantity not greater than a grain of mustard-seed ; but still the 

 results were attended with danger. In attempting to collect the gas 

 produced in its explosion, by heating a very small quantity under 

 water in a curved tube, the tube was shattered with great violence, 

 and the author received a wound in the transparent cornea of one 

 eye, from which he has not yet recovered. 



Explosions equally violent were afterwards witnessed by Mr. Chil- 

 dren and Mr. Warburton, even without confinement : when a small 

 globule of the oil was thrown into a glass of rolive oil, oil of turpen- 

 tine, or naphtha, the glass, though strong, was in each instance shi- 

 vered to pieces. 



When a globule larger than a grain of mustard-seed was touched 

 under water by phosphorus, the explosion was so violent as to break 

 any glass vessel in which the experiment was made. But when 

 smaller quantities were employed, a gas could be collected which, by 

 the experiments hitherto made, contains no oxygen and no inflam- 

 mable gas. 



When thrown into the solutions of phosphorus, in ether, or alco- 

 hol, it detonates most violently ; but neither ether nor alcohol alone 

 exhibit any violence in their action upon it. 



' In muriatic acid it gives off gas rapidly, and disappears without 

 explosion. Various experiments were also instituted with other sub- 

 stances, as sulphur and resin, among others, but without any remark- 

 able effects. 



From the general tenour of these experiments, the author thinks it 

 probable that the substance here examined is a compound of azote 

 and chlorine, formed by the decomposition of ammonia ; while the 

 hydrogen of the ammonia unites with another portion of chlorine, 

 and forms muriatic acid. 



The heat and light produced during the expansion of this oil into 

 gaseous matter, is considered by the author to be without a parallel 

 in our present collection of chemical facts ; and the suddenness of 

 the explosion more instantaneous than that of any compound hi- 

 therto known. 



On a remarkable Application of Cotes's Theorem. By J. F. W. 

 Herschel, Esq. Communicated by W. Herschel, LL.D. F.R.S. 

 Read November 12, 1812. [Phil. Trans. 1813, p. 8.] 



This communication includes an application of Cotes's theorem to 

 conic sections in general ; but the application noticed in the title re- 

 lates to the parabola in particular, and it may be thus enunciated. 



If any number of radii vectores S P be drawn from the focus to the 

 curve, making equal angles P S P with each other ; and if an equal 



