Dec. 8, 1882.] 



KNOWLEDGE 



455 



adopted by Mr. Siemens [also from the 100,000th sug- 

 gested by Mr. Williams]. If, instead of considering 

 solely the resistance opposed liy such a gas to the motion 

 of our planet, we carry our thoughts to the consequences 

 which its existence would have on the existence of our own 

 air, we find that unless we multiply our 700,000,000,000 

 of cubic metres by 100,000, and reducing the density 

 sought to 000,000,000,000,000,1 kg., our atmosphere 

 would, in a few instants, be swept off (Jialayee) by the 

 frictional action [prfssion cxercee ex amont'] of the inter- 

 planetary atmosphere. 



[What follows is curious.] 



M. Faye is perfectly justified in saying that it is not this 

 or that degree of rarefaction, but void (vf mutf'-i; that is) 

 that the astronomer requires, to ensure the stability of 

 motion demonstrated by his analysis. This void doubtless 

 brings to the ground the doctrine, which some pretend is 

 so clear, which attributes aU the phenomena of the universe 

 to the movements and shocks of material atoms inde- 

 pendent of each other. It will be necessary, one 

 day Tor another, that this doctrine should yield up 

 its life, that its defenders should resign themselves 

 to the admission that there is ■ something more in 

 the world than matter in motion. In a remarkable 

 letter to Bentley, Newton said that no man possessed 

 of a power of forming a sound opinion in matters 

 of philosophy could admit that between two bodies which 

 seem to attract each other at illimitable distances, some- 

 thing does not exist which causes this relation ; but he 

 adds forthwith : " Is this intermediary material or imma- 

 terial 1 I leave this for the reader to decide." For that 

 great genius there was certainly no uncertainty {Vhuyrti- 

 tv.de n'e.risldit certtiineni' iitl on this last point; bu the 

 refrained, perhaps with good reason, from proposing to his 

 contemporaries a solution which might have seemed to 

 them unimaginable (itinaisissablf), and which, it seems, is 

 still so for so many minds in our own time. 



DEATH-WARXING. 



THE letter of Mr. Sinclair (650, p. i39) in last week's 

 Knowledge, suggests to me to relate an even more 

 extraordinary circumstance which occurred in my own 

 family some years ago. The Baroness (my own mother-in- 

 law) had a maid, a Westmoreland woman, who came from 

 a place called Bongate, near Appleby. Subsequently to the 

 death of her mistress she became our housekeeper, and died 

 in the bouse whence I write these lines, after a continuous 

 service of thirty-five years with mother and daughter. 

 Before leaving her native county she had known a woman 

 by sight, but, to the best of my belief, was not sufficiently 

 intimate with her to speak to her. Well, one night she 

 dreamed that this woman (of whom, be it particularly re- 

 marked, she had neither seen nor heard anything for some 

 years), she dreamed, I say, that this woman took a piece of 

 cord from a drawer, went into an outliouse, and hanged 

 herself; and that, after some time, her daughter came 

 in and cut her down. So appallingly vivid was this 

 dream that when she came down to dress her mistress 

 the next morning, she, in an agitated manner, told hor 

 of it, giving the details as I have given them here. Some 

 little while afterwards a friend sent her a Westmoreland 

 newspaper, which contained, iiifi'r alia, an account of the 

 suicide of the subject of the maid's dream, and report of 

 the inquest, whence it appeared that on the very night on 

 v Inch the dream occurred this woman did take a piece of 

 ro[)e from a drawer, did go into an outhoust- and hang 



herself ; and that her daughter did subseqv\ently come in 

 and cut her down ! The point to be noted in this .strange 

 (but absolutely true) story is, I venture to think, the nar- 

 ration of the dream by (1. to the Baroness, within two or 

 three hours of its occurrence, thus precluding any ex post 

 ftrf,, embellishment of it when the news of the objective 

 suicide arrived. I inclose my name and that of the 

 principal actors in the matter. N. 



THE LIBRATION OF SENSATIOX. 



IN my little book of "The Revised Theory of Delight, 

 I showed, at length, that the received explanation of 

 the phenomena of the ocular spectra is full of discrepancies 

 and insufficient. And in that work and my previous 

 lectures on Lightj I endeavoured to explain my hypothesis 

 of the Libration of Sensation, or that tendency of the 

 nervous reaction from an initial sensation, to one of an 

 opposite kind, and in the ratio in which that initial sensa- 

 tion was a departure from the rifctn state, or state of 

 repose of the nervous system. This law not only holds 

 good with respect to the sense of sight, but to the whole 

 human system, and thus we find that the great law of 

 compensation, which holds in the Kosmos, also ol)tains in 

 the human constitution — viz., that whatever aberration 

 takes place in excess of a mean state must be compensated 

 by an equal and opposite one in defect of that state. 



The fact that the sentient eye is the only " colour box," 

 and that external to this there is nothing but mechanical 

 vibrations, is not sufficiently present to the minds of most 

 persons to prevent them from reasoning as if colour were 

 a property of the vibrations themselves. This is the case 

 with reference to the phenomena of the ocular sp'^ctni, 

 which are regarded as external eflects instead of, as they 

 are, internal phenomena of the sentient being, due to the 

 reactions of the nervous system, and which may be 

 experienced after an initial sensation, though the eye be 

 closed against all external vibratory action. An initial 

 impression of a black spot in a white field is succeeded 

 by a sensation of a white spot in a black field. An im- 

 pression of a dark colour in a white field by its light, 

 opposite and complementary colour, in a black field, and 

 vice versd. 



We find, then, that similar changes in colour to those 

 produced by the cooling of beads, alluded to by your corre- 

 spondent in last week's issue, also occur in the retina by 

 the decadence of an initial sensation, for the comple- 

 mentary spectra are entirely subjective phenomena. After 

 a very strong initial sensation of colour, the sequent 

 spectra endure a sufficient length of time to enable anyone 

 to experiment with them. For instance, after being dazed 

 by the sun, the spectrum of any one of the sequent sensa- 

 tions or spectra, say, dark red on a white field, will 

 become light green in a dark field, and will become 

 dark red again in a light field. Here, then, the \-ibratory 

 reaction is changed within the nervous system itself, so as 

 to produce sensations of difrercnt coloui-s. In consequence 

 of these and other investigations I came to a conclusion 

 very similar to that of your correspondent, which I ex- 

 pressed in a letter to the editor of the BuUdcr, April 2:i, 

 1881, in the following words : — "It is curious that, with 

 the endeavour to establish the close analogy between liglit 

 and sound, that a body appearing of a certain colour has 

 never been accounted for, as we account for a musical 

 string responding to the note to which it has been attuned, 

 and to that vibration only. In like manner, bodies only 

 emit that colour viljratiou to which their molecular consti- 

 tution is attuned." W. C.wf. Thomas. 



