♦ KNO^VLEDGE ♦ 



[November 1, 1887. 



feeling that the child she had loved had been near hei", she 

 knew not how ; Rokesniith's start when he heard the name 

 of the adopted child (his own name) ; his remarks about 

 John Harmon : these all obviously show who he is, and 

 Dickens meant them to be so understood. We have no 

 doubt he meant the identity of Datchery to be similarly 

 recognised by those who knew his method. (Of course, we 

 have verv decisive evidence in regard to " Our Mutual 

 Friend " that Dickens did not care to make any mystery of 

 the Ilokesmitli assumption ; for long before the end of the 

 story we find Rokesmith talking about the details of the 

 events which had attended his disappearance from among 

 living men. There is no reason to suppose that he intended 

 to be at all more eai-eful about the identity' of Datchery — a 

 little later on though, perhaps, than the story actually 

 reached.) 



But it may be well to consider, in passing, two other stories, 

 each turning in marked degree on a mystery — viz. " By 

 Pi-oxy " and " The Moonstone." The former novel admirably 

 illustrates our subject. For although the plot is about as 

 unlike that of " Edwin Drood " as any plot could well be, 

 we have in " By Proxy " a man supposed to be dead, watch- 

 ing the man who is guilty of worse than murder — seeing 

 that he has withheld the price at which he had, as he believes, 

 bought his own life at the cost of a better one. Now in 

 " By Proxy " it is essential to the interest of the latter part 

 of the story that the reader shall not be able to conceive 

 how Conway can have been saved, while yet he shall feel 

 that Conway must be alive. Accordingly we have not the 

 slightest direct suggestion of Conway's escape from death, 

 except in the rush of a hasty messenger past the flying 

 wretch Conway had saved. Yet we know that somehow 

 Conway's escape has been achieved ; and at a stage of the 

 story corresponding to that which " The Mystery of 

 Edwin Drood " had reached when the pen fell from the 

 author's hand we have decisive evidence that Conway lives ; 

 nor does any one fail to understand the assumption by which 

 he is enabled to meet his daughter without announcing his 

 escape to the man for whom he has designed a fearful punish- 

 ment. 



The mystery in " The Moonstone " is altogether different 

 in character, yet equally serves to illustrate our argument ; 

 because in " The Moonstone," as in " By Proxy," "Edwin 

 Drood," and " Our Slutual Friend," the chief interest of the 

 plot (we do not say of the novel as a whole, be it understood) 

 turns on the solution of the mystery. It is noteworthy that, 

 while in the other stories the reader is left in little doubt as to 

 the general solution of the mystery, though altogether 

 doubtful as to details, in " Edwin Drood " and " The 

 Moonstone " even the general meaning of the events de- 

 scribed in the earlier pages is left in doubt, at least for all 

 except the very keenest readers. There are touches in the 

 chapters of " Edwin Drood " preceding Edwin's disappear- 

 ance which show any one who understands Dickens's manner, 

 and has an ear for the music of his words, that Edwin 

 Drood is not actually to be killed, and that the Drood who 

 really is to be seen no more is the light-hearted whimsical 

 boy of the earlier pages. But that evidence was not for all 

 readers. It may even be doubted whether Dickens himself 

 knew how clearly he had disclosed Edwin's real fate fur 

 those who knew his voice, any more th:in many of us know 

 how full of meaning are certain tones of our voice for those 

 who know us well. Nor can one analyse the effect of such 

 tones in a written story any more than in the speaking 

 voice. In reading " Edwin Drood," we (who write these 

 lines) never felt any doubt from the first page to the last 

 that Drood was to be one of the living character's at the 

 close of the story. Yet we could not have given any definite 

 reason for the faith that was in us, until at least the scene 



where Grewgims tells Jasper that Edwin and Rose had 

 cancelled their plighted troth. In " The Moonstone " no 

 one, we should imagine, has an}' idea as to the real solution, 

 numerous though the facts are which that solution, and that 

 alone, is to explain. There arises a vague suspicion, as we 

 read about Frank's smoking, his sleeplessness, the difference 

 with the doctor, and afterwards that Frank had slept well 

 on the night of the robbery, that these little details are 

 significant. I'osKihli/, if the story had been left unfinished, 

 the same kind of analysis which we have ourselves given to 

 " The Mystery of Edwin Drood " might have led to these 

 points being so carefully considered and put together as to 

 disclose the general nature of the interpretation of the 

 Moonstone mystery — so much, for instance, as flits, that 

 Frank had himself removed the diamond when under the 

 influence of opium, that somehow Ablewhite had got hold of 

 it, and that in some way unknown Miss Verinder was 

 certain Frank had taken it from her cabinet. This would 

 have explained the position of affairs at the close of the first 

 part of the story, and one can imagine no other explanation 

 consistent with our certainty that Frank has not wittingly 

 had any part in abstracting the diamond, that ]\liss Verinder 

 is quite incapable of the trick attributed to her by the 

 detective (really keen though he is shown to be), and that 

 Ablewhite has in some way got the diamond into his hands. 

 The details of the disappearance, however, and of course the 

 singularly effective clearing up of the mystery in this fine 

 story (in our opinion far the strongest of all Mr. Collins's 

 novels), could never have been guessed, no matter how close 

 an examination any reader might have given to the earlier 

 part of the story. Yet even these details are suggested 

 when as yet the end of the story is far off. 

 {To he continued.) 



COAL. 



By W. Mattieu Williams. 



N my paper preceding this I described the 

 general nature and magnitude of the problem 

 of colliery ventilation. I will now endeavour 

 to render intelligible the methods of ventila- 

 tion that are actually adopted, omitting, for 

 reasons already stated, any account of air- 

 ])unips, blowing machines, fans, and other 

 devices for mechanical ventilation, and confining myself to 

 the principle explained in my last, which in this country is 

 almost universally applied. This principle is simply the 

 setting of air in motion by its own gravitation by connecting 

 two columns of air of different weights in such wise that 

 the heavier shall descend and the lighter rise in nearly the 

 same manner as do unequally weighted scale- pans. 



As it is easier to diminish the density of a given column 

 of air than to increase it, especially where fuel is abundant 

 and cheap, the work of differentiation is carried out by 

 operating on the upcast rather than the downcast shaft. 

 We have simply to raise the mean temperature of one shaft 

 above that of the other, and the required movement is 

 started. The air falls in the cooler and rises in the hotter, 

 forcing its way from the cooler to the hotter through such 

 intervening passages as may connect them. These two 

 shafts may be only a few yards distant from each other, and 

 yet the current of air may be so tortured that it shall travel 

 some miles in passing between. 



The diagram shows how this is done. D represents, in 

 horizontal section, the downcast shaft, U the upcast shaft, 

 a, b, c, and d are passages or cross i-oads with doors. It is 



