264 
Steel, 
mal cliarcoal is decomposed by a less heat than charcoal 
of pine or oak ; a consideration that I regard as of great 
importance in this country, both as to the facility of mak- 
ing steel, and the economy of wood. From some expe- 
riments of Vauquelin, steel seems to contain phosphorus ; 
if so, it was probably made by animal charcoal ; which 
is always preferred for case-hardening. 
That steel, whether cemented steel, or cast steel, is 
merely charcoal combined with iron, will appear from the 
various processes of making it. But the fact can be prov- 
ed by direct experiment. Take 100 grains of filings of 
pure malleable iron ; as much of cemented or blistered 
steel ; as much of cast steel. Dissolve each of these sepa- 
rately in spirit of salt and water, half and half, in a warm ij 
place. The solution of the iron will furnish no black powder 
remaining undissolved ; the two other solutions will ; and 
the cast steel the most. Pure charcoal is not capable of 
being dissolved in any acid.* Indeed the common mode 
* The following facts relating to the indestructibility of charcoal, 
are well worth attending to. “ The beams of the theatre at Her- 
a culaneum were converted into charcoal by the lava which over- 
a flowed that city, and during the lapse of between 1 7 and 1 800 ( 
u years, the charcoal remains as entire as if it was made but yester- 
1 a day, and will probably continue so to the end of the world. The i 
u incorruptibility of charcoal was known in the most antient times. 
u The famous temple of Ephesus, was built upon wooden piles 
a which had been charred on the outside to preserve them. 3 Wat- 
<£ son s s essays 48. 
u It is said there still exists charcoal made of grain in the time 
u of Caesar, which is in so compleat a state, that the wheat may be 
u distinguished from the rye. Willichu 
“ About 40 years ago, a quantity of oak stakes were found in the 
a bed of the Thames in the very spot where Tacitus, says that the 
t£ Britons fixed a vast number of such stakes to prevent the passage 
“ of Julius Caesar and his army. They were charred to a consi- 
a derable depth, retained their form compleatly, and were firm at 
w the heart, Dr. Robison 
