120 
Salt of hartshorn manifested no particular effect with the water 
which first came over ; but with the bituminous liquor, allowed to 
stand until it had become clear, it caused a considerable ebullition, 
the mixture becoming foul and red; and in a few days U became 
thickened and of the colour of tar, the surface of it, as well as the 
sides of the phial, being covered with a bituminous pellicle. By 
exposing the black gTitty powder, in a retort, to a red heat for two 
hours, the neck of the retort became thinly incrusted with something 
that resembled a saline concrete, but which he found to be only a 
bituminous matter. 
The black powdery residuum being kept red hot in a close vessel, 
for a longer time than he thinks would be sufficient to have reduced 
an equal quantity of vegetable charcoal, still emitted a thick heavy 
smoke, when sprinkled on a red hot iron ; and upon farther ex- 
posure to heat, in an open vessel, an astringent mineral salt was left, 
but no other saline matter, which, he thinks, together with the bitu- 
minous nature of its products, affords a sufficient proof of this fossil 
wood differing from all known wood, belonging to the vegetable 
kingdom, and of its being an actual mineral substance. 
I cannot close this letter without, in justice to Professor Hollman, 
noticing the hard fate of his useful observations, or rather disco- 
veries, on this subject. In the year 1^53, he delivered to the Royal 
Society of Gottingen, a most excellent dissertation on the origin of 
marine, and other foreign substances, contained in the earth ^ ; 
which appeared in the third volume of the Society’s Transactions, 
iknother dissertation, the one from which we have derived so much 
information f, was also decreed to appear in the fifth volume of the 
same work ; but foreseeing, what actually happened, that the latter 
paper would be excluded from public view, in consequence of 
* De Corporum marinorum, aliorumque peregrinorum, in Terra continente, Origine. 
f Loci inemorabilis, in quo ingens Ligni fossilis Copia reperitur, Descriptio. 
