Expet-imi^nfs on Detonation. 169 



-experiment a fmoke arifes which afTumes the form of a crown, in die fame manner as phof- 

 "phoiated hydrogenous gas when fpontaneoufly inflamed in a calm atmofphere. 



5. The fulphure of iron, or martial pyrites, inflames rapidly, but without noife, when 

 ■triturated in a metallic mortar with the fuper-oxigenatcd muriate of pot-afii. This mixture, 

 ^hen ftruck on the fteel anvil, detonates ftrongly with a red flame. 



6. The red fulphure of mercury, or cinnabar, and thr fulphuratcd oxides of mercury, deto- 

 nate by the (Iroke with the fuper-oxigenated muriate of mercury (q. pot-afli) ; but they do 

 not take fire with the fulphuric acid. Charcoal alone mixed with this fait has the fame effects. 



7. Sugar, the gums, fixed and volatile oils, alcohol, or ether mixed with the fuper-oxigen- 

 ated muriate cf pot-afh, fo that thefe laft liquid combuftible fubllances formed a parte with 

 the fait, have the property of fulminating very (Irongly by the ftroke of the hammer. They all 

 «mit a very ftrong flame on detonation. Thefe mixtures do not detonate nor take fire by 

 fimple trituration. Some of them take fire in the concentrated fulphuric acid. Their com- 

 buftion in this cafe is flow and fu-cceflive. 



8. All the fubllances before mentioned, which, wlien mixed with the fuper-oxigenated 

 muriate of pot-afli, take fire and burn in an inftant, and with confiderable noife, by the 

 rapid prefliire of the ftroke of the hammer, produce a much ftronger detonation when 

 wrapped up in double paper, which compreffes them together before the ftroke. 



9. The eleftric fhock froin a ftrong machine, by the charge of a battery of large furface, 

 caufes all the foregoing mixtures to detonate in the fame manner as concuflion ; and in this 

 cafe alfo they emit a ftrong light. 



To all thefe fafts the authors add, that it was already known that gunpowder deto- 

 nates by a violent blow or fudden preflure ; but they obferve, that the ftroke rpuft be much 

 ftronger than is neceffary to produce fulmination in all the mixtures of combuftible fub- 

 fiances with the fuper-oxigenated muriate of pot-afli, and that its detonation is far from 

 being equally remarkable with thofe produced by the new fait. 



With regard to the theory of this fiiigular phenomenon, it appears to them to be the 

 fame as that publiftied by BerthoUet relative to the detonation of fulminating filver by the 

 flighteft contaifl. Preflure, and more particularly that which is eftefted in a very fliort 

 time, as by a blow, favours the union of oxigene with the combuftible body. This com- 

 bination efl"ecled by the oxigene, feparated all at once from the fuper-oxigenated muriate 

 of pot-afli, is accompanied by a fudden expanfion, and inftantaneous formation of gafe- 

 ous matters, which ftrike and comprefs the furrounding air with fuch velocity as to pro- 

 duce a confiderable noife. The light, the vapour, and the odour peculiar to each com- 

 buftible body made ufe of, prove that a true inflammation takes place, and that the ftrong 

 detonation is owing to its violence and rapidity. 



The inflammation produced by the concentrated fulphuric acid arifes from the difen- 

 gagemcnt of the fuper-oxigenated muriatic acid in gas, by means of which the combuftible 

 matters mixed with the fait take fire ftill more rapidly than in the ordinary oxigenatcd mu- 

 riatic acid gas. 



Vol. I— July 1797. Z IX. ^ 



