order of the series as follow:-1. peat; 2. lignites ; 3. bituminous coal; 4. anthracite. To each of these substances or rather suits of substances, for each comprehends numerous varieties-modern science, as already intimated, attributes a vegetable origin; unless, indeed, we except the last-in which case, as we shall find, the exception will have to encounter strong evidence against its admission. The latter three bituminous fuels above named, seem to bear a striking relation in the gradual change which, in each case, the ligneous structure has undergone, to the geological newness or antiquity of the strata amidst which they commonly occur. The carboniferous group or true coal measures, in which the vegetable origin of the beds, however undoubted, is by no means obvious, are comprehended, according to the preceding scale, in the medial order; above which, we have the lignites, where woody structure is very apparent, and sometimes but little changed; while below, even in the primary rocks themselves, we find anthracite, in which every trace of organic structure is commonly obliterated.* Nearly all the rocks lying above those termed primitive-more properly, primary-contain animal remains: the generally striking character and occasional profusion of these, give to the fossiliferous strata a peculiar interest, not only in the eyes of a student in natural philosophy, but to the casual observer: they are likewise of vast importance in aiding

* Professor Jameson considered what he calls "glance coal" and "black coal," to be original chemical deposits, "as little connected with vegetable remains, as the shells that occur in limestone are with that rock." His reasons were, that these coals occur in primitive rocks as gneiss, mica slate, clay slate, &c., and appear to be contemporaneous formations. More recent and extended investigation, however, does not seem to lend confirmation to such an opinion.

FOSSILIFEROUS STRATA.

39

The

us in the identification of remote formations. beautiful principle that every distinct geological deposit had its appropriate suite of fossils, was first promulgated by Mr. W. Smith, who may justly be styled the Father of Modern Geology. The formation of the Geological Society in 1807, the object of which was rather to collect and publish facts than to propound or support theories, has been vastly contributive to the diffusion of an interest in this study through the most intelligent classes of the community.

CHAPTER III.

PEAT.

Early use of Peat for Fuel-Its abundance in various countries-Hypothesis of the discovery of its inflammable nature-Notices of the knowledge and application of Peat in ancient times-Theories of the origin of Turf deposits-Various opinions and testimonials concerning the bituminization of Vegetable Matter-Plants which chiefly enter into the composition of Peat bogs-Irish and Scotch bog mosses-Extraneous remains found in Peat bogsAnalogy between the depositions of some stratified turbaries and the Coal formation—Method of digging and preparing Peat in Ireland-Varieties of Peat-Old practice of charring Turf-Popular prejudices in favour of Peat Fuel.

THE most common article of domestic firing in the less wooded districts of this country, previously to the general use of pit coal, was turf or peat, a species of fuel still dug and burnt in large quantities in those places where it abounds, and where wood or coal are scarce or unattainable. It would be difficult to say at what period the material now under consideration was first applied to its long-acknowledged

purpose:

IMPORTANCE OF PEAT.

41

useful that it was used, as it is at present, from a very early period of our history, there can be no doubt and, in the absence of ligneous and mineral fuels especially, its great abundance, easy obtainment, and singular production, arrest attention to one of those sources of comfort and convenience, which an infinitely wise Providence has opened in the store-house of Nature for the benefit of mankind. Peat claims some notice in a work like this, not only because that, in common with wood, it was an early, and still continues to be an article of extensive domestic consumption as fuel; but also, and more especially, because that, like coal, it may be regarded in some sort as a fossil, being dug out of the earth: it has even been considered, erroneously perhaps, to exhibit the progress of transformation from the living vegetable fibre to the compact lignite or jet: indeed, Mr. Williams, a respectable mineralogical writer, supposed that antediluvian peat bogs have been sources of fossil coal; an opinion which has not wanted the countenance of much higher authority.

It has been supposed that the discovery that various kinds of earth, or peat, might be used as fuel, would originate in accident in some place destitute of wood; as, not only may the heat of the sun, after long drought, occasion combustion,* but a spark, falling fortuitously on a turf moor, during a dry summer, often sets it on fire, and the conflagration it occasions generally lasts so long, that it cannot escape notice. Tacitus mentions a notable instance of

* Instances of this are not wanting in our day. The heat was so great during the autumn of 1833, that the ground in some places spontaneously took fire, especially in Switzerland: and in the summer of the present year (1834), a moor took fire owing to the long-continued drought, in Livonia.

this kind, which occurred in the neighbourhood of Cologne, not long after the foundation of that city. In Siberia, about the middle of the eighteenth century, a village, on account of its marshy situation, was removed to another place, and the remains, that they might be the more easily carried away, were set on fire. The flames having communicated to the 'soil, which was inflammable, occasioned great devastation; and when Gmelin was there, it had been burning for half a year.*

It seems, however, scarcely necessary to have recourse to such an hypothesis for suggesting the use of peat as an economical fuel; the presence and appearance of the substance itself, must at once have led to its application as a fuel by those who had previously witnessed vegetable matter of any kind in a state of combustion. Certainly, its value for this purpose was very early understood in Germany; for Pliny says expressly, that the Chauci pressed together with their hands a kind of mossy earth, which they dried by the wind rather than by the sun, and which they used not only for cooking their victuals, but also for warming their bodies.† The earliest certain account of turf in the middle ages, which Beckmann had met with, was a letter of sanction, by which an Abbot Ludolph, in the year 1113, permitted a nunnery near Utrecht to dig cespites for its own use, in a part of his vena. Now, there can be no doubt that vena signifies a turf-bog, and cespite turf. On the same authority, we are told that the words turba, turbo, turbæ ad focum, turfa, occur for turf in the years 1190, 1191, 1201, and 1210. The traffic in this kind

*Beckmann's Hist. Inventions. I. 335.

+ Hist. Nat. Lib. XVI. c. 1.