After this brief notice of those organic _compounds_ that have been recognized in or produced from peat, we may give attention to the elementary composition of peat itself. Like that of the vegetation from which it originates, the organic part of peat consists of Carbon, Hydrogen, Oxygen and Nitrogen. In the subjoined table are given the proportions of these elements as found in the combustible part of sphagnum, of several kinds of wood, and in that of a number of peats in various stages of ripeness. They are arranged in the order of their content of carbon. -----------------------------------+----------+-----+-------+-----+------- | |_Car-|_Hydro-|_Oxy-|_Nitro- |_Analyst._|bon._| gen._ |gen._| gen._ -----------------------------------+----------+-----+-------+-----+------- 1--Sphagnum } | Websky |49.88| 6.54 |42.42| 1.16 2--Peach wood } undecomposed |Chevandier|49.90| 6.10 |43.10| 0.90 3--Poplar " } | " |50.30| 6.30 |42.40| 1.00 4--Oak " } | " |50.60| 6.00 |42.10| 1.30 5--Peat, porous, light-brown, | | | | | sphagnous | Websky |50.86| 5.80 |42.57| 0.77 6-- " porous, red-brown. | Jæckel |53.51| 5.90 | 40.59 7-- " heavy, brown. | " |56.43| 5.32 | 38.25 8-- " dark red-brown, | | | | | well decomposed | Websky |59.47| 6.52 |31.51| 2.51 9-- " black, very dense | | | | | and hard. | " |59.70| 5.70 |33.04| 1.56 10-- " black, heavy, }best quality| " |59.71| 5.27 |32.07| 2.59 11-- " brown, heavy, }for fuel. | " |62.54| 6.81 |29.24| 1.41 -----------------------------------+----------+-----+-------+-----+------- From this table it is seen that sphagnum, and the wood of our forest trees are very similar in composition, though not identical. Further, it is seen from analyses 1 and 5, that in the first stages of the conversion of sphagnum into peat--which are marked by a change of color, but in which the form of the sphagnum is to a considerable extent preserved--but little alteration occurs in ultimate composition; about one _per cent._ of carbon being gained, and one of hydrogen lost. We notice in running down the columns that as the peat becomes heavier and darker in color, it also becomes richer in carbon and poorer in oxygen. Hydrogen varies but slightly. As a general statement we may say that the ripest and heaviest peat contains 10 or 12 _per cent._ more carbon and 10 or 12 _per cent._ less oxygen than the vegetable matter from which it is produced; while between the unaltered vegetation and the last stage of humification, the peat runs through an indefinite number of intermediate stages.