Chemical Preparations. 289 



You will find a bottle containing some condensed fumes, arising 

 during the preparation of fulminating mercury. I am now satisfied 

 that the fumes contain spirits of nitrous ether, nitrous acid and mer- 

 cury, and some uncondensable gas or gases, and vapor of water. 

 Sixteen measured ounces of alcohol give ten measured ounces of 

 condensed fluid. I have ascertained that nitric acid, of sp. gr. 1.34, 

 can be made to compensate for its weakness, by increasing the pro- 

 portion of it to the mercury and alcohol. One hundred grains of 

 mercury, to two measured ounces of acid of this strength, and two 

 measured ounces of alcohol, made as good fulminating mercury as 

 I have ever seen. 



I send you two small phials of nitrated sulphuret of potash, or yel- 

 low powder, as it is usually called in this country. It is far less per- 

 fect than such as I used to make, when in the habit of preparing it 

 some years ago. You will perceive by burning it, in small parcels, 

 upon the hearth or otherwise, that it takes fire with readiness, and 

 burns much quicker than common powder. I have made some 

 hundred pounds of it, which were eagerly bought up by hunters and 

 sportsmen for priming fire arms, a purpose which it answered most 

 admirably ; and, but for the happy introduction of powder for prim- 

 ing, which is ignited by percussion, it would long since have gone into 

 extensive use. 



With this preparation I have had much to do, and I doubt whether, 

 in the whole circle of experimental philosophy, many cases can be 

 found involving dangers more appalling, or more difficult to be over- 

 come, than melting fulminating powder and saving the product, and 

 reducing the process to a business operation. I have had with it 

 some eight or ten tremendous explosions, and in one of them I re- 

 ceived, full in my face and eyes, the flame of a quarter of a pound 

 of the composition, just as it had become thoroughly melted. 



The common proportions of 3 parts of nitre, 2 parts of carbonate 

 of potash and 1 part of sulphur, gave a powder three times quicker 

 than common black powder ; but, by melting together 2 parts of 

 nitre and 1 of carbonate of potash, and when the mass was cold 

 adding to 4 J parts of it, 1 part of sulphur — equal in the 100, to 54.54 

 dry nitre, 27.27 dry carbonate of potash and 18.19 sulphur — a great- 

 ly superior composition was produced, burning no less than eight and 

 one half times quicker than the best common powder. The substan- 

 ces were intimately ground together, and then melted to a waxy con- 

 sistence, upon an iron plate of one inch in thickness, heated over a 



Vol. XXI.— No. 2. 37 



