Section III, 1889. [ 41 ] Teans. Roy. Soc. Canada. 



VIII. — Oil the Hygroscopicity of certain Canadian Fossil Fuels. 



By G-. Christian Hoffmann, F. lust. Chem., Chemist and Mineralogist to the Geological 



and Natural History Survey of Canada. 



(Presented May 8, 1SS9.) 



The experiments, in this connection, here recorded, and which were conducted upon 

 material in all stages of alteration, ranging from surface peat to anthracite, were all 

 carried out under precisely similar conditions. 



The various fuels w^ere all reduced to as near as possible the same state of mechanical 

 division, having been ground just sufficiently flue to allow of their passing a sieve of 

 ninety holes to the linear inch. The material — of vfhich, in each case, one gram and 

 a-half was employed — was placed iu low, broad, flat-bottomed, straight-sided, very light 

 glass bottles, provided with accurately ground glass stoppers. In the drying experiments, 

 the specially constructed staging — which carried thirty of these bottles — supported by 

 glass legs, stood over a glass dish (almost equal in area to the mouth of the bell jar) con- 

 taining strong sulphuric acid; the whole being covered by a bell jar with ground rim 

 resting r;pon an accurately ground plate. In the absorbtion experiments the glass dish 

 containing the sulphuric acid, was replaced by one containing a shallow stratum of water, 

 over which were heaped shreds of filtering paper, and the bell jar enclosing the experi- 

 ments was in turn covered by another of much larger dimensions — an arrangement which 

 effectually prevented the deposition of dew. The temperature of the room (which was 

 artificially heated — the work having been carried out during the winter months) in 

 which the experiments were conducted, ranged from 65° to 70' F. The experiments were 

 all made in duplicate — the two experiments with the same fuel being carried out, as 

 affording a better check, on separate occasions. 



In some preliminary experiments, fifteen of the lignites, in duplicate, were exposed 

 to an absolutely dry atmosphere for 48 hours, at the expiration of which time 

 they were found to have parted with the greater part of their moisture. They were then 

 further exposed for consecutive periods of 36, 44, 68, 68, 48, and 42 hours, during which 

 periods they incurred an additional loss (in each case the mean of the thirty experiments) 

 of respectively 1'2.5, 084, 0'*73, 0"59, 0"29, and 0'15 per cent, of water (the los.s — taking the 

 mean of the two experiments with each of the fifteen fuels — ranging from 0'92 to 1'66, O'll to 

 0-97, 0-51 to 0-80, 0-36 to 0-75, and 0-19 to 0-37 per cent.) or a total loss of 8-85 per cent, for the 

 additional 306 hours. A still further exposure for consecutive periods of 93, 120, 70, and 

 90 hours, was attended by a further loss (in each case the mean of the thirty experiments) 

 of respectively 0'48, 045, 015, and 019 per cent., or an aggregate loss of 127 per cent, 

 for the 373 hoiirs (additional to the jirevious 354 hours) exposure. The peat, which had 

 already been submitted to an exposure of 354 hours, was further exposed for consecutive 



Pec. Ill, 1889. 6. 



