136 



KNOWLEDGE 



[June 1, 1897. 



whereas if the same copper point be applied to a hot spot, 

 a warm sensation is easily recognized. Accordingly, on 

 the fingers we have touch spots — hot spots and cold spots. 

 Generally speating, the temperature spots are insensitive 

 to pain ; in fact, though a fine needle be pushed into a hot 

 or cold spot — apart from being a pressure spot — no pain is 

 felt. If a metallic point, conveying a current of electricity, 

 be carried along the surface of the skin, very strange 

 sensations will be felt in its course. There will be cutting- 

 pain points, thrill points, tickle points, and actual dead 

 points. 



Prof. McKendrick is puzzled with the effects of rapid 

 induction currents on the skin elements. The currents do 

 not produce pressure in the ordinary sense ; nor do they 

 produce sensations of temperature ; nor are they of a 

 painful character. So far as he is aware, no observations 

 have been made on the stimulation of sensory skin-nerves, 

 except with reference to the production of reflex acts. 

 But he has been directing his attention to the effects of 

 stimulation of the skin — varying in number, in intensity, 

 and in rhythm — on the brain. 



Of course, it is well known that a single stimulus applied 

 to a motor nerve will cause a single twitch, and the 

 distinguishing characteristics of such twitches are equally 

 well known. If the stimuli come in very rapid succession, 

 muscular rigidity is the result. Accordingly, considerable 

 care is necessary in the carrying out of the experiments. 



Prof. McKendrick introduced into the circuit of the 

 primary various interrupters — clocks, metronomes, vibrat- 

 ing strings, and tuning forks — to ascertain their effects. 

 These varied in speed from one to two hundred vibrations 

 per second. The terminals of the secondary coil were 

 carried to the platinum foil in the vulcanite troughs con- 

 taining the salt solution ; and he dipped his fingers into 

 the troughs. He could readily mark the successive stimuli 

 up to fifty per second. When the number of stimuli was 

 raised to one hundred and twenty per second, there was a 

 thrill comparable to the effect of very rapid musical beats, 

 causing disagreeable roughness. Above that the effect was 

 of a more solid character, which could not be analyzed 

 into details. 



By repeated experiments Prof. McKendrick has esta- 

 blished the fact that the sensory nerves of the skin can 

 appreciate electrical stimulations corresponding in number, 

 rhythm, and intensity to the notes or chords of a com- 

 plicated piece of music. But the stimulation of the skin 

 (so far as is yet known) can give no accurate appreciation 

 of the pitch of individual tones ; although, when stimula- 

 tions are comparatively few iu number, the sensition is 

 rough, and different from the continuous sensation 

 occasioned by very numerous stimulations. Nor can the 

 stimulation of the skin give any idea of the quality of 

 tone. He cannot detect any feeling like that which leads 

 us, when we intelligently listen to music, to be, as it were, 

 searching for the tones that determine scales. Still, there 

 remain the elements of rhythm, and this includes the 

 duration of individual tone?, and the intensity of tone. 

 As to time and duration, he has fouud the sensations quite 

 distinct. After careful and repeated tests of the varieties 

 of simple and compound times, he has found no difiiculty 

 in distinguishing the one from the other. 



It is from these experiments tliat the Professor is 

 sanguine about influencing the braiu of the deaf through 

 the fingers, so as to make them understand some of the 

 elements of music. Yet he admits that, so far as his 

 experiments guide his judgment, the music thus transmitted 

 to the deaf will be, as it were, " on one plane." Several 

 deaf persons on whom he has experimented have appeared 

 to be startled with the new sensations, and when it was 



explained to them that there was something of these new 

 sensations in music they apparently had increased 

 pleasure, because they could more intelligently sympathise 

 with those who had the coveted sense of appreciating 

 music. To some extent, then, the deaf may be able by 

 refined thrill transferences to follow Congreve when he 



"Music lias charms to sootlio rhe savage breast, 

 To softea rocks or bend a knotted oak ; 

 I've r^ad that things inanimate have moved. 

 And, as with living souls, have been iuform'd 

 By magic numbers and persuasive sound." 



There is, too, a correlation of the senses which demands 

 more close attention in scientific inquiry. Sensations of 

 sound affect those of colour. Raff, an eminent musical 

 composer, said that he saw the colour of the flute to be 

 blue, the hautboy yellow, and the cornet green. Sounding 

 a tuning fork may cause a colour to be seen more vividly. 

 Smells, tastes, touches, may influence sounds ; a loud 

 sound may appear more subdued when one shuts his eyes. 

 All are familiar with the close relation of sight and 

 taste. In the same way smell affects sounds, and tastes 

 influence colours. If a very bright light be made to fall 

 upon the skin of the hand, the sensitiveness to tempera- 

 ture is increased. If the skin be excited by quiet currents 

 of electricity, pleasurable sensations may be produced ; if 

 regulated stimuli be applied to the fingers through the 

 isolated troughs, duration, time, and rhythm may be 

 recognized. May we not, then, send nervous impulses 

 through the finger-tips which may radiate to the cerebral 

 centres of the ear, and thus excite processes resulting in 

 something like the consciousness of music ? Certainly to 

 those who once heard, and had lost their hearing by an 

 accident, the sensation can be more easily assimilated ; in 

 them electrical stimulations of the skin can more easily 

 awaken a kind of cerebral music, which will remind them 

 of what they once so much enjoyed, touching the finest 

 strings that reach the heart ; music — 



" Which they have loved long since, and lost awhile." 



THE AGE OF MOUNTAINS.-III. 



By Professor J. Logan Lobley, F.G.S. 



TOWERING far above all other groups and ranges 

 of mountains in the European area, the Alps 

 form the greatest and most conspicuous physical 

 feature of its land surface. With a summit of 

 fifteen thousand seven hundred and thirty-two 

 feet above the level of the sea, and stretching for five 

 hundred miles without a gap of less elevation than six 

 thousand feet, they form, with their lateral extensions (the 

 Pyrenees on the west and the Balkans on the east), the 

 great wall dividing the main mass of the continent from its 

 southern peninsular portions. If the Jura, the Apennines, 

 and the Carpathians be regarded as offshoots — which they 

 really are — we find comprised in one great mountain system 

 all the principal ranges of Europe, with the exception of 

 the Ourals, the Scandinavian chain, and the sierras of the 

 Iberian peninsula. 



Of the central portion of this great mountain system — 

 the Savoy, the Swiss, and the Tyrolese Alps — the petro- 

 logical structure has long been generally known. For 

 this we are indebted to the labours of Boue, Brogniart, 

 Elie de Beaumont, Geslin, Heer, and to our own great 

 geologists, Sir Roderick Murchison and Sir Charles 

 Lyell — the last-named of whom, by his masterly reason- 

 ing and brilliant exposition, has removed much obscurity. 

 But a more detailed knowledge of the structure of the Alps 



