494 



NATURE 



{Sept. 2 2, 1 88 1 



of the fibre contributes to the formation of the substance, 

 is shown by the formation of a similar compound from pure 

 celhilose and dextrin. A chloi'inated product (CjuHj^CljOio) 

 has-been obtained from this blaclc substance, its properties 

 are similar to those of the aromatic substance described 

 in a previous paper (loc. cit.). The production of this spongy 

 substance is usually a destructive one, and attended with 

 an evolution of COj and the production of acetic acid, 

 &c. It is not, however, necessarily so, for when the action 

 of the sulphuric acid is arrested before the evolution of carbonic 

 dioxide, a reddish brown solution is obtained, from whicli 

 when poured into water a copious flocculent precipitate is ob- 

 tained, of a body very similar in chemical properties to the black 

 substance described above. The chlorine substitution products 

 are easily converted into astringent bodies, producing dai-I<- 

 coloured precipitates with iron salts and copious coagulation 

 with gelatine. These facts, together with the following : — (a) 

 Meissner and She^pard's conclusion that the hippuric acid of 

 herbivorous urine is derived froni an aromatic body present in 

 the fodder, apparently a form of cellulose, which the authors 

 have identified as similar to the characteristic consititueut of bast 

 fibre ; {b] the previous demonstration by the authors of the 

 homogeneous nature of jute fibre, and that in its resolution the 

 percentage yield of cellulose may be increased apparently at the 

 expense of the aromatic constituent ; (c) that the process of 

 liquification (or the formation of tannin-like substances) is said 

 by microscopists to be due to an intrinsic modification of the 

 sub.-tances of the cell-walls, i.e., of the cellulose, and not to an 

 infiltration of the substances present in the cell cavity ; (i/) the 

 numerous cases in which tannic acid is formed at the expense of 

 plant structures of the nature of cellulose — lead the authors to con- 

 clude that, until the contrary is proved, lignin must be regarded 

 as derived from cellulose by chemical modification. The 

 spong)' black substance, previously described, dries to a hard 

 mass resembling cannel coal, \vith which the authors have com- 

 pared it, and have obtained similar products of chlorination 

 and nitration, and further support of the opinion that coal is not 

 carbonaceous in any more special sense than alcohol, but is 

 rather, as supposed by Balzer, composed of C, O, H, N bodies, 

 which are genetically, if not ho:iiologously related. The authors 

 suggest that cellulose, lignite, peat, lignin, and anthracite are 

 terms of an infinite series differentiated under the conditions of 

 their formation. 



Hydration of Salts and Acids, by C. F. Cross, B.Sc— The 

 metliod adopted by the author for investigating the rate of 

 hydration of a substance consisted in exposing about i gramme 

 of the substance in a bcll-jar of 2000 c.c. capacity, to an atmo- 

 sphere saturated with aqueous vapour. After a critical investi- 

 gation of the probable errors, the "Jolly" Federwaage was 

 used to make the numerous weighings required, and thus the 

 metliod of observation was rendered very expeditious. The 

 paper contains diagrams representing the velocities of hydration 

 for cert lin salts and oxides. The author has observed that, under 

 these " artificial " conditions of exposure, all the soluble salts 

 examined deliquesce. This takes place in some cases without 

 previous hydration, e.g., with potassium bichromate, and in such 

 cases the water may be removed by pressure bet« een blotting 

 paper. In other cases, e.g., with CuSO^, the salt deliquesces 

 after uniting with water of chemical hydration, and in a different 

 manner. It would therefore appear that the continuity of the 

 phenomena of hydration and solution, as regards the determining 

 cause, is demonstrated by these observations. 



On Colliery Explosions, by W. Galloway. — The author gave 

 an account of his experiments made to show the influence of 

 coal-dust in colliery explosions. In July, 187S, he made three 

 sets of experiments with different kinds of apparatus. In the 

 first set, in which coal-gas was used instead of fire-damp, and 

 the gas and air were carefully measured, and then coal-dust 

 added, it was shown that 2 per cent, of gas, mixed with air, was 

 rendered inflammable when coal-dust was added ; 3 per cent, of 

 gas made this mixture slightly explosive ; 4 per cent, made it 

 still more explosive ; and 5 per cent, produced a violent explo- 

 sion. The total quantity of gas and air mixture was little more 

 than a cubic foot. In the second set it was shown that the 

 return air of a mine containing 2 per cent, of fire-damp became 

 inflammable when coal-dust was added to it. In the third set 

 the explosion of a mixture of air and fire-damp was made to 

 raise and ignite coal-dust scattered along the floor of an artificial 

 gallery 70 or 80 feet long, and 14 inches square inside. The 

 flame of the fire-damp explosion alone was found to be 7 feet or 



8 feet long ; the flame of coal-dust in pure air was 35 feet or 

 40 feet long ; and the flame of coal-dust in the return air em- 

 ployed in the first set of experiments was 80 or 90 feet long. 

 The publication of the e results called further attention to the 

 subject, and after the Seaham explosion the Home Secretary 

 requested Dr. Abel to inquire, amongst other things, into the 

 influence of coal-dust in promoting that disaster. Prof. Abel 

 made experiments near Wigan, and obtained results similar in 

 kind to the author's, but different in some respects. In July of 

 the present year the author made experiments with apparatus of 

 the following description : A sheet-iron cylinder 6 feet long by 

 2 feet in diameter, closed at one end and open at the other, had 

 its open end bolted to a wooden gallery 126 feet long by 2 feet 

 square inside. One end of the wooden gallery was thus closed by 

 the sheet iron cylinder, an explosion chamber, and the other end was 

 open. Sixsheets of newspaper wereplaced between this open end of 

 the explosion chamber and this gallery, and a tight joint was en- 

 sured by means of screws. Rather less than 2 cubic feet of fire- 

 damp was carefully measured and introduced into the explosion 

 chamber. The wooden gallery contained only pure air. The 

 air and fire-damp contained in the explosion chamber was tho- 

 roughly mixed by means of an appropriate mechanical arrange- 

 ment, and the mixture was exploded. The explosion burst the 

 sheets of paper, and the resulting flame travelled about 12 feet 

 or 14 feet along the gallery, and as suddenly disappeared. The 

 gallery was then strewed with a layer of the coal-dust from J inch 

 to \ inch thick along its floor, and some was placed on shelves 

 which stood in sets of three, one above the other, at distances of 

 10 feet from each other, along the gallery. The same arrange- 

 ment as before was then made in regard to pieparing for a fire- 

 damp explosion, exactly the same quairtity of fire-damp being 

 measured, mixed, and exploded. By this explosion of the fire- 

 damp mixture the coal-dust was raised in a cloud throughout the 

 whole length of the gallery, part of it was projected out into the 

 air to a distance of 20 feet or 30 feet beyond the end, and, after 

 the lapse of an appreciable interval of time, the flame found its 

 way to the end of the gallery and flashed out through the cloud 

 of du>t to a greater or less distance according to circumstances. 

 The greatest length of flame thus obtained «ith coal-dust and 

 pure air was 147 feet on one occasion, and from 100 feet to 140 

 feet very often. He considered that these results proved in the 

 most convincing manner that coal-dust formed an inflammable 

 mixttu'e with pure air, and they settled once for all the question 

 as to how an explosion in one district of a dry and dusty mine 

 could penetrate to the most distant parts of every other district 

 of tire workings in the same mine. In conclu^ion the author 

 spoke of the necessity of keeping the floors of mines damp, and 

 thus lessening the dangerous influence of coal-dust. 



SECTION C— Geology 

 A preliminary Account of the Working of Dowherboltom Cave 

 in Craven during August, 1881, by E. B. Poulton, M.A., 

 F.G.S. — Dowkerbottom Caveis 1250 feet above the sea, betw-een 

 Arncliffe and Kiln-ey. Its mouth is merely a fall in the roof of 

 the cave, which stretches from either end of the fissure thus 

 formed. The original mouth is not now vi ible, but is probably 

 to be found at the foot of a slope to the south. During most 

 of its course the chambers and passages of the cave are not 

 separated by any great thickness of rock from the ground above, 

 and thus other falls must be expected to occur. The eastern 

 divi ion of the cave is about 450 feet long, and has three fine 

 chambers separated by two passages, the first very short, and the 

 second very long. This division ends under high ground, and 

 the true mouth mu^t be in the other, or western cave. The last 

 chamber is characterised by mechanical depo its — blocks of 

 limestone fallen from the roof and a stiff brown clay beneath. In 

 the other chambers and passages are chemical depo.-its — hard 

 and sift stalagmite. The western division is smaller, but also 

 contains three chambers and two passages. It must be about 

 250 feet long. Chemical depo-its, with some falls from the 

 roof, are present throughout. In former w orkings by Mr. Farrer, 

 Mr. Denny, and Mr. Jackson, the first chambers » ere explored 

 in their surface layers at least, and here were found the numerous 

 metal and bone ornaments and implements, t gether with the 

 bones of animals usually found in the historic layers (of Romano- 

 British age) in caves. The second passages have al o been 

 worked, and pait of the second chamber on the eastern side. 

 Other parts of the cave appear to be quite untouched. The great 



