120 GEOLOGY OF OHIO. 
circumstances—and which is a kind of distillation—are, peat, lignite, 
bituminous and anthracite coal, graphite and asphaltum, which are 
solids; carbonic acid, carburetted hydrogen, etc., which are gases. Of 
these, all the solids, excepting asphaltum, are residual products, while 
that substance and the liquids and gases are the evolved products, or dis- 
tillates. Neither of these substances has any definite formula of compo- 
sition, as each individual specimen may represent a distinct stage of 
the process of bituminization. The first mineralized solid formed from 
vegetable tissue is usually called lignite, if derived from wood; peat, if 
from herbaceous vegetation. These terms are, however, somewhat vaguely 
employed; for while the term peat is used only for the brown, spongy 
mass—mostly derived from mosses—which is found in our surface bogs 
and is now forming, the name lignite is given not only to bituminized 
woody tissue, but to the Tertiary and Cretaceous coals, even though they 
may have been formed of the same materials and in the same way as 
our recent peat beds. 
Such being the relations of the carbon series, 1t is manifest that to 
express each one by a distinct formula, as though they were mineral spe- 
cies or definite chemical compounds, is a misstatement of the truth of 
nature, and is calculated to create misapprehension. This will be obvi- 
ous to any one who will compare the hundreds of careful analyses which 
have been published of the different hydrocarbons. The nature of the 
changes which take place in the formation of peat and lignite from veg- 
etable tissue will be seen by the comparison of typical examples of each 
given below: | 
Vegetable tissue. Loss. Peat. 
CAT DORR eet ARE usec roe cateeeremeee 49.1 21.50 27.6 
Tes KOR O}2X85 O45605 Godade bed000800 oan 20NhOd 260060 frIGoH0600 6.3 3.00 2.8 
COR: AEXEN I) bo pcicry cose CORE COGCNES Acne bn Groton ae RanNB ae caer 44.6 29.10 15.5 
Wood. Loss. Lignite. 
Car OTe ee Ree re Seer Ulate See duane sta 49.1 18.65 30.45 
TER POURO ED 5 09905000060000 600000000 06000 54000090 bud 6.3 3.25 3.05 
OKiy PON assaaece ceceaneanp nme nladactsiuec ste snes eo ence 44.6 24.40 20.80 
In this process the evolved products represented by the loss are water, 
carbonic acid, and carburetted hydrogen, or petroleum. 
Where peat or lignite have been long buried in the earth they have 
suftered still further loss and change, and are converted into what is 
termed bituminous coal, as will be seen in the following example: 
Lignite. Loss. Bituminous Coal. 
LOLI CO yay Gan cal Aber ARR aRC AS RAB ABEA Grados 60000 30,45 12.35 18.10 
FLV AROS EIR acct. sa ccnsine an euuettateetatons 3.05 1.85 1.20 
ORR PED, cocdoa ago000 cod9bd00 040060 098009 095008 on0000 20.30 18.13 2.07 
