106 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



per cent, of good coke, containing 90 per cent, of carbon, is obtained 

 from high-grade peat ; though hard and compact, it retains the 

 peat-structure. The tar, a mixture of the more readily condensed 

 hydrocarbon compounds, rarely exceeds 4.5 per cent, of the dried 

 peat, varies much in quantity and is a black viscous liquid. Sub- 

 jected to fractional distillation, it yields, after separation of water, 

 ammonia, light and heavy oils, paraffin wax, creosote and asphalt. 

 The crude oils are said to be identical with those of petroleum in 

 properties and appearance. The character of the tar water, contain- 

 ing lighter or less readily condensed compounds, depends in part 

 on the character of the peat ; the fibrous, less decomposed peats yield 

 more methyl alcohol and acetic acid with less ammonia than those 

 which are darker, thoroughly decomposed and structureless, which 

 contain more combined nitrogen. This tar water contains ammo- 

 nium salts, acetic and other acids as well as methyl alcohol. 



The permanent gases vary with the character of the peat, the 

 quantity of water and the temperature at which the coking is done, 

 there being in every case a considerable proportion of air. The less 

 decomposed peat gives the greatest quantity and the poorest quality. 

 The variability in composition appears from two analyses, the first 

 being from the Ziegler plant at Oldenburg and the other from that 

 at Beuerberg ; the percentages are in volumes ; 



I. II. 



Carbon dioxide 27.4 15.5 



Oxygen 2.2 i.i 



Nitrogen 22.5 21.9 



Carbon monoxide 8.6 20.4 



Carburetted hvdrogen 14.8 1 



QH. : i.oj ^2.4 



Hydrogen 23.6 28.6 



The gas burns with a feebly luminous flame. Von Ammon^-'^^ has 

 published results obtained during destructive distillation of Schiefer- 

 kohle from Grossweil, which is a well-decomposed peat with 60.59 

 of carbon. Two samples, each weighing one kilogramme, were 

 tested, one retaining the woody structure, the second resembling 

 earthy brown coal. The results are very different from those ob- 

 1^^ L. V. Amnion, " Bayerische Braunkohlen," etc., p. 10. 



