Ingredients in Banded Bituminous Coal. ilt 



more ' of a solution so strong that it looks coal-black in bulk. Where the 

 vitrain is quite pure there is no undissolved ddbris at all ; but if fine streaks' 

 are visible in part of the original material, a few small spores arid fine debris' 

 may be found at the bottom of the flask. ' 



Ulardin also goes largely into solution ; the " head " of froth, however, is 

 less in quantity and subsides more quickly. After standing, some dehiis 

 settles at the bottom of the vessel, and this d4h'is has, under the microscope, 

 certain' definite characteristics (see p. 478). The solution appears quite black 

 in bulk' and clear tea-coloured in a fine tube. • > ; 



Durain forms no real froth, and the " solution " is rather paler than that of 

 clarain, at first looking equally dark, owing to the number of very minute 

 opaqub particles suspended in it. After standing, the debris settles down and 

 is seen to be considerable in quantity. Its microscopic appearance i^' 

 described below (p. 478). 



Fusain forms no froth and no true solution, the water generally remaining' 

 colourless, or being no more than straw coloured. The particles of debris 

 are vety heaVy and numerous, settling more quickly than from the other 

 coal ingredients (c/. p. 478). 



In order to present these differences graphically, equal weights of each of 

 the four' eoEll constituents were taken, treated ultimately with eqxlal 

 amounts of waiter, allowed to stand overnight so that the debris settled, th6: 

 clear solution then decanted off, leaving in each vessel 20 c.c, with the 

 debris. Each vessel was then well shaken up, so that whatever was,, in each 

 was mixed and held in suspension, and then from each a narrow tube was 

 filled. These four tubes were standing vertically, when settled the contents 

 presented the appearance shown in fig. 5, Plate 12 (coloured illustration). 



The proportion of debris thus separated was much greater in the f usaih 

 tube than in the others; and in the tube the particles settled relatively 

 quickly; and Were big, black and opaque. The durain tube showed less 

 debris, filling about one-third of the tube when the particles had settled, and 

 the particles themselves were smaller, and not all opaque, but some were 

 brown and translucent, while the solution was tea coloured, and in it were 

 for long suspended fine amber coloured fragments of plant tissue. 



The clarain tube showed still less debris, about one-sixth or less of the 

 tube Settled quickly, but for some time the finer generally amber colou'red 

 and clear particles of plant tissue, spores, etc., remained suspended in the 

 clear solution, which was the colour of strong tea. 



The true pure vitrain had no dibris, save for an intrusive speck or two. 

 The clear solution was strong tea coloured. 



Micro-photos of the dibris of the above experiments show some of their 



