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NATURE 



[Dec. 25, 1879 



many striking deviations from the ordinary Mongol 

 standard. The elder Retzius had long ago distinguished 

 four more or less marked ethnical groups in Finland 

 itself, apart altogether from the intruding Swedes, 

 Russians, and other foreigners. These, however, are 

 now reduced to two only, which a careful investigation 

 of the materials supplied by archaeology, tradition, the 

 Norse Sagas, the old national songs and philology, com- 

 bined with an extensive study of a vast number of crania 

 and living subjects, have enabled the younger writer to 

 fix with some approach to precision. 



Of the two, the Tavastian and the Karelian, he regards 

 the latter as the genuine national type, in this differing 

 from the commonly received opinion. The Karelians, 

 occupying the country more to the east, are of slighter 

 build, but better proportioned and taller than the 

 Tavastians, of a light brown complexion, with longer 

 head, narrower and less heavy features, long, straight, 

 and pointed nose, dark hazel eyes, chestnut or dark hair 

 falling in ringlets over the shoulders, open and animated 

 expression, though still with a serious cast. The Tavastian, 

 on the contrary, is of a much more solid, compact, and 

 coarse build, middle size, light or ashy complexion, but 

 always lacking the rosy tints peculiar to the Teutonic 

 peoples, with straight silken hair of a flaxen colour, and 

 often yellow at the tips, broad square head, short snub 

 nose, dilated nostrils, slightly oblique greyish blue eyes, 

 sullen and unsympathetic expression. 



This description obviously corresponds far more closely 

 with the common Mongoloid type than does that of the 

 Karelians. Yet in the writer's opinion the latter are the 

 true descendants of Illmarinen, the hero of the Kalevala, 

 and the scene of his exploits is laid in the region still 

 occupied by them. The Tavastians he regards as a 

 distinct ethnical element of doubtful affinities, though 

 allied on the one hand with the Esthonians of the Baltic 

 provinces, on the other possibly with the Lapps of the 

 Arctic regions. 



The question, as already remarked, has been advanced 

 one stage ; but much remains to be done before we can 

 expect to see all the difficulties removed by which it is 

 surrounded. Meanwhile it seems impossible to agree 

 with M. Retzius, that the Karelians, rather than the 

 Tavastians, represent the true Finnish type. Both have, 

 no doubt, largely absorbed foreign elements. But if both 

 are alike branches of the Mongolo-Tatar family, as has 

 been hitherto supposed, and as their speech appears to 

 place beyond question, it follows that of the two the 

 Tavastians must be regarded as the nearest to the 

 common stock. The Karelians are, of course, much the 

 finer race, both physically and intellectually, and national 

 prejudice may, therefore, feel inclined to regard them as 

 the purer branch. But, ethnologists will probably be 

 disposed to look on the improvements as due rather to 

 a greater absorption of foreign elements, Teutonic or 

 Slav, if not Lithuanian. They occupy a country which 

 may well have been peopled by some of these races before 

 their arrival, whereas the dreary lacustrine region of 

 Tavastland must have been all but destitute of inhabitants 

 previous to its occupation by the advanced wave of 

 Finnish migration. A. H. ItEANE 



RESEARCHES ON TELEPHONE VIBRA- 

 TIONS 

 DR. RUDOLPH KONIG, the well-known constructor 

 of acoustical apparatus, has recently brought before 

 the Physical Society of Paris a research of the highest 

 interest, upon the difference of phase which exists be- 

 tween the vibrations of a transmitting and a receiving 

 telephone. In a paper published more than two years 

 ago, Prof, du Bois-Reymond discussed the conditions 

 which determine the intensity and the phase of different 

 sounds transmitted telephonically ; and from theoretical 



considerations deduced the conclusion that sounds of low 

 pitch suffered greater loss by transmission than shrill 

 ones, and that every simple vibration was retarded in 

 phase by a quarter of an undulation. The former of these 

 actions would produce an alteration in the timbre of the 

 voice as received at the end of the line : the latter effect 

 would remain unappreciated by the ear, since the retarda- 

 tion of phase was the same for waves of all periods. 

 More recently Helmholtz has attacked the question in a 

 paper in the Annalen of Wiedemann (" Telephon und 

 Klangfarbe "), and, with a theoretical treatment of the 

 question based upon somewhat deeper analysis, has de- 

 duced the results that all sounds are weakened by trans- 

 mission in almost a constant proportion irrespective of 

 their pitch, and that the difference of phase between the 

 vibrations of transmitter and receiver are very small. 

 Dr. Konig has endeavoured to put these conflicting 

 speculations to the test of experiment, and with marked 

 success. 



It may be well, perhaps, to indicate the elementary con- 

 siderations which led du Bois-Reymond to predict the 

 existence of this hitherto unobserved difference of phase. 

 The currents by which sounds are carried from the trans- 

 mitter to the receiver in the Bell telephone are induction 

 currents, excited in a coil of insulated vi ire by the vibra- 

 tions of the iron diaphragm in front of the permanent 

 magnet which serves as a core. The intensity of these 

 induced currents is greatest when the vibrating diaphragm 

 is moving with the greatest velocity. But the maximum 

 velocity of the diaphragm does not occur at the moment 

 when the displacement of the diaphragm is greatest. To 

 non-mathematical readers this fact may be explained by 

 reference to the movements executed by a simple pendu- 

 lum. As the pendulum swings backwards and forwards 

 the " bob " comes absolutely to rest at the moment when its 

 displacement to one side or the other is the greatest, and 

 it moves with the greatest velocity when it passes through 

 the " point of rest " mid-way between its two extreme 

 positions. Mathematically, the matter is equally simply 

 stated. The displacement of a body executing a simple 

 harmonic motion is determined by an equation of the form 



u = a cos ~- , where the values of 11 pass through a 



regular series of maximum and minimum values as / in- 

 creases. These successive values are geometrically 

 represented by the heights of the ordinates of the 

 well-known harmonic curve or sinusoid, the distances 

 along the horizontal axis O x being proportional to the 

 times. Thus the telephone diaphragm originally at 

 rest begins to move towards the magnet under the in- 

 fluence of the voice. The displacement, which at the 

 origin is nothing, increases until at A it becomes a 

 maximum. Owing to its elasticity the diaphragm flies 

 back, and passing rapidly through its point of starting 

 suffers a displacement in an opposite sense. These 

 movements are graphically represented on the harmonic 



curve by the passage of the curve across the axis at B to 

 its minimum or greatest negative displacement at C, the 

 curve recurring from the point D. Now the equation 

 which represents the velocity of the moving point will be 

 obtained from the equation of the displacement by dif- 

 ferentiating with respect to time. This gives us an equa- 

 tion of the form — 



it = — r 



T T V T T 2 /' 



