Intelligence and Miscellaneous Articles. 231 



The explosibility of incandescent nitre with water was illustrated 

 in the small way, by heating a portion in a platina capsule by the 

 flame of a hydro-oxygen blowpipe, and sudden immersion in the 

 liquid. So active was the explosion, that a portion of the resulting 

 hydrate flew out upon the operator. Yet, when thrown in the same 

 state upon molasses or sugar, no explosion ensued : nevertheless, 

 when a capsule containing nitre heated to the point of volatilization 

 was struck with the face of a hammer coated with sugar melted upon 

 it and made to adhere by moisture, a detonation took place. A still 

 more powerful detonation was produced as follows : — Upon an anvil 

 a disc of paper of three inches in diameter was laid, covered with 

 pulverized sugar : over the sugar was placed another similar disc, 

 covered with pulverized nitre : a bar of iron rather wider than the 

 discs at a welding heat was then held over them, and subjected to a 

 blow from a sledge. An explosion, with a report like that of a 

 cannon, ensjied. 



Instructed by the facts and considerations above stated, it is inferred 

 that the explosions which contributed to extend the conflagration in 

 New York, as above mentioned, arose from the reaction of the nitre 

 with the combustible merchandize with which it was surrounded. It 

 is presumed that as soon as the fire reached any of the gunny bags it 

 must have run rapidly through the whole pile, by means of the inter- 

 stices necessarily existing between them, the nitre with which they 

 were imbued causing them to deflagrate. Much of the salt being 

 thus brought to the temperature of fusion, it must have run about 

 the floor, reached the combustibles, and soon found its way to the 

 next story through the scuttles which were open. All the floors 

 must have been rapidly destroyed by the consequent deflagration, far 

 exceeding in activity any ordinary combustion. Meanwhile, the nitre 

 being all liquefied and collected in the cellar in a state of incEin- 

 descence, and the merchandize conglomerated by the fusion'of sugar 

 and shell-lac, aided by the molasses, the weight, the liquidity, and 

 temperature, must have produced all the conditions requisite to in- 

 tense detonations. The floors having been consumed, the store must 

 have been equivalent to an enormous crucible of twenty feet by ninety, 

 at the bottom of which were nearly 300,000 lbs. of nitre, superficially 

 heated far above the temperature producible by any furnace, so as to 

 convert the reagents into nascent aeriform matter under a pressure 

 of half a million of pounds. The intense reaction, however, would 

 not permit of durable contact. At each impact the whole mass must 

 have been thrown up explosively, and hence the successive detona- 

 tions. But the chemical reaction, the heat, and the height of the fall, 

 growing with their growth, and strengthening with their strength, the 

 last elevation was succeeded by the thundering report and stupen- 

 dous explosion of which it has been an object to afford a satisfactory 

 explanation. — From the Journal of the Franklin Institute. 



PREPARATION OF IODIDE OF LEAD. BY M. T. HURAUT. 



The author remarks that several processes are known for the pre- 

 paration of iodide of lead ; all of which give tolerably satisfactory re- 

 sults. When carefully employed they yield a pure product, and the 



