342 REPORT—1896. 
classes of substances, one soluble in alkalis, forming coloured solutions, 
and a second insoluble. 
By the use of phenol as a solvent E. Guignet has extracted from 
2 to 4 per cent. of a brown solid from coal, which is precipitated from the 
solution by alcohol. The finely powdered coal treated with nitric acid 
yields solutions containing oxalic acid and trinitroresorcinol ; the insoluble 
residue contains apparently nitro-compounds, or bodies similar to nitro- 
cellulose. A portion of this residue is dissolved by caustic alkalis and 
ammonia, forming brown-coloured solutions. 
Guignet, led by the formation of trinitroresorcinol, as mentioned above, 
attempted to obtain resorcinol! by fusion of the coal with caustic soda and 
distillation in a bath of molten lead, but obtained ammonia and aniline 
only. The residue after this treatment was, however, found to be partially 
dissolved by water, forming dark brown solutions, from which acids pre- 
cipitated out humus-like substances. Guignet concludes these bodies are 
derived from the cellulose-residues of the coal, and that the trinitro- 
resorcinol owes its origin to the resinous and wax-like constituents. 
During the session 1889-90 Mr. Saville Shaw, Lecturer in Chemistry 
at the Durham College of Science, Newcastle-upon Tyne, made some ex- 
periments on the action of a mixture of concentrated sulphuric and nitric 
acids on bituminous coal. The coal, in a finely powdered condition, was 
allowed to remain for three weeks in contact with the mixed acids, and 
then poured into a large volume of water, filtered and thoroughly washed. 
The dried residue differs but slightly in appearance from the original coal, 
but had evidently undergone change in composition, as after this treat- 
ment it gave as much as 77 per cent. of ‘ volatile matter,’ whereas the coal 
contained but 27 per cent. ; further when heated in a test-tube it ‘ puffs ” 
with slight flame, resembling in this respect gun-cotton. A considerable 
portion of this ‘ nitro-coal’is soluble in caustic alkalis, yielding very dark 
brown solutions, from which on acidifying bulky dark brown precipitates 
are formed. The precipitates, washed and dried, form brilliantly black 
friable masses, which have lost the semi-explosive properties of the original 
‘nitro-coal.’ Methyl alcohol dissolves some 11 per cent. of the ‘nitro- 
coal,’ the solution yielding a black scaly product on evaporation, which, 
when heated, suddenly decomposes, leaving a very bulky residue of carbon. 
Attempts to prepare reduction products from this nitro-coal were un- 
successful. 
In a note published in the ‘Proceedings of the Chemical Society’ 
(1891-92, p. 9) R. J. Friswell described the results obtained by treating 
finely powdered coal with dilute nitric acid ; a considerable portion of the 
coal is thus converted into a black insoluble acid, which behaves very much 
as a nitro-compound. 
Mention should also be made of the investigations of Mr. Watson 
Smith, published in 1891, on the soluble and resinoid constituents of 
bituminous coal. The soluble material extracted by benzene from a 
Japanese coal Mr. Watson Smith has shown to contain phenols, nitro- 
genous organic bases, and also some aromatic hydrocarbons. 
In a previous report experiments with various solvents on a bitu- 
minous coal from the Hutton seam in the county of Durham were 
referred to, but, owing to the small yields obtained, this method of 
attacking the problem as to the nature of the proximate constituents of 
coal has been relinquished. 
The oxidation of the finely powdered coal with aqueous solutions of 
