O'd produced from the Leaves of the Laurel Cherry. 153 



I divided it like oil into small globules, which again soon 

 united. 



I must here mention another plisenomenon, which I 

 cannot pass over with indifference. livery time I heated, 

 for a considerable time, the Prussian blue of the shops over 

 a spirit lamp, in order to prepare the gas, so that the Prus- 

 sian blue was pretty well decomposed, and had become 

 brownish black, I observed, when the glass was broken, 

 still hot, that the Prussian blue here and there inflamed in 

 the same manner as pyrophorus prepared from alum and 

 charcoal, or like sulphate ot potash and charcoal, but without 

 a blue tiame. The Prussian blue was always heated over a 

 bpirit lamp, so that it was impossible an inflammation could 

 arise. Three or four experiments, repeated for this purpose, 

 confirmed this observation, but I was obliged to break the 

 glass while hot. The same thing did not take place v^ith 

 prussiate of iron, but T made the experiment only once. 



The production of pyrophorus by this process may be 

 explained in the followmg manner : — The Prussian blue of 

 the shops contains, as is well known, argillaceous earth 

 (potash) and a little sulphuric acid : now, as the prussic 

 acid and carbonic acid arc disengaged, a decomposition of 

 the sulphuric acid may take places the sulphur which is 

 produced may unite with the free argillaceous earth; and in 

 this manner we may be conducted to the well known theory 

 of pyrophorus. If this explanation be not agreeable to nature, 

 we have perhaps still obtained more. In my experiments 

 a partial decomposition only took place each time, as only 

 some particles, and those of the largest size, inflamed. 

 This observation might conduct us to the nature of the 

 substance which in this case is the agent, and these expe- 

 riments may perhaps furnish abler chemists with matter for 

 future research. 



XXIV. Experiments on the Oil produced from the Leaves 

 of the Laurel Clierry. By C. liohOFF of Magdeburg*. 



L HAVE made Rome experiments with the 'distilled oil of 

 the leaves of the laurel cherry, the result of which I here 

 communicate, because they are different from that of the 

 experiments of M. Bucholz with distilled oil of bitter 

 almonds. 



As M. Bucholz employed potash with success for tlfe 



• From the same woik as the preceding arricle. 



separation 



