OS pRtJsstc Acid. ^5y 



^iBiseotts state, 1 decomposed prussiate of mercury by mitii* 

 feitic acid, as directed by Mr- Proust. After the air con- 

 tained in the vessels had escaped, and a strong smell of 

 prussic acid was perceivable, I received the gas over mer- 

 cury* Thus I obtained several jars full of an elastic fluid, 

 inflamtnable, and with a powerful smell, which appeared td 

 me to be gaseous pi'ussic acid. However, on continuing 

 the process, I perceived, that drops of a peculiar liquid ac- 

 'quiredthe gaseous state, as soon as they reached the sum- , 



init of the jar, and depressed the column of mercury consi» 

 durably. The temperature then was at 20° [68° F.] ; and 

 the next morning, the temperature being only 1-2° [53-6° F.]* 

 1 observ*ed, that the bulk of the gas I had obtained was 

 greatly diminished, and that a liquid was deposited in the 

 jars, where there was none before. I had then no longer 

 any doubt, that the prussic acid was a very volatile liquid ; 

 fcnd after several trials, which I shall pass over, I succeeded 

 in procuring it readily in the following manner. 



^ I took a tubulated retort, into which I put prussiate of Method of 

 nlei^ury ; and to the neck of the retort I adapted a curved P^o'="""8 ''^ 

 tube, one end of which I inserted into a small two-necked 

 phial, containing a mixture of chalk and muriate of lime ; 

 tlie chalk being intended to saturate the muriatic acid, that 

 Ihight escape from the retort, and the muriate of liox^ to re- 

 tain the water. From this phial another tube proceeded to 

 i i^cond, containing also muriate of lime; and from this 

 issrued a third tube, terminating in a third phial vtrith a 

 ground stopple, intended to receive the prussic acid. The 

 apparatus being thus arranged, &nd all the phials sur- 

 rounded with a cooling mixture of two parts ice and one 

 salt, 1 poured some slightly fuming muriatic acid into the 

 fetort, and applied to it a gentle heat. The prussiate of 

 mercury soon dissolved, and the Hquor appeared to boil. 

 In fact vapours were evolved, which partly condensed in thti 

 neck of the retort, forming streaks like alcohol. The pro- 

 cess was stopped the moment water began to rise; though 

 more prussic acid might still be obtained: but it is better to 

 s<*|jarate the first product, and afterwards resume the process. 



All the prussic acid comrhonly condenses in the first Rectification 

 jfjhial.- If no water pass over, the muriate of lime remains" ^h^*"**- 

 •Vol. XXXL—April, 1812. S solid. 



