68o 
The Formation of Coal. 
[Odtober, 
The experiments of M. Daubree upon anthracite, and the 
no less interesting experiments of M. Baroullier upon coal, 
lead us to think that the transformation into coal is brought 
about by the adtion of heat and pressure upon the vegetable 
matters. In order to analyse the phenomenon, M. Fremy 
arranged a series of tests, in which the vegetable tissues, 
on the one hand, and, on the other, those substances which 
most frequently accompany them in the organisation, were 
heated to between 200° and 300° for some hours in glass 
tubes sealed at both ends. 
In these experiments M. Fremy observed a great modi- 
fication. The tissues became black, brittle, and free from 
water, acids, gas, and tar ; but they retained their original 
organisation, and furnished a fixed produdt, offering no 
resemblance to coal. 
The learned academician then submitted to the same test 
a certain number of bodies produced by organism, such as 
sugar, starch, gum, &c., and arrived at very different 
results. These bodies were transformed into substances 
having a certain analogy to coal : they were black, shiny, 
often melted, and quite insoluble in acids and alkalies. 
The analysis of these bodies, which M. Frdmy designates 
by the name of coally substances, has demonstrated the 
complete analogy of their composition with that of natural 
coal. Coal from gum gives in analysis almost the same 
quantities of carbon, hydrogen, and oxygen as natural coal. 
From these coincidences of composition M. Fremy draws 
the conclusion that the elements contained in the vegetable 
cells — such as sugar, starch, and gum — play an important 
part in the production of coal. 
This result was doubtless a very interesting one ; but, in 
order to complete it, it was necessary to explain how the 
tissues of vegetables could lose their organic form and pro- 
duce the amorphous mass called coal. Besides this, also, it 
was necessary that the tissues should be proved to be 
capable of undergoing the same coal transformation which 
was realised by operating upon the non-organic bodies which 
accompanied them. 
The studies of the eminent chemist with respeCt to lignite 
and peat now proved of great assistance to him. He had 
seen in these combustibles the ulmic acid appear in propor- 
tion as the ligneous tissues lost their organisation. When 
a peat was advanced he only found insignificant remains of 
organic tissue, but then it contained from 50 to 60 per cent 
of ulmic acid. On examining the fossil wood M. Frdmy 
found pretty thick, black, and shining layers of ulmic acid 
