516 



NATURE 



[August 28, 19 19 



hundred songs, which are recorded and analysed in 

 the present volume. It will thus be seen that the 

 tribe possesses a very elaborate system of folk-songs, 

 mostly associated each with a particular object, and 

 it is to be noted with interest that, with the advent 

 of civilising influences, phonographs have become 

 much sought after by the Sioux themselves. 



The distinctly tribal life of the Teton Sioux prac- 

 tically ceased with the suppression of the Sun Dance, 

 the last of which was held in 1881, the final buffalo 

 hunts occurring in the two following years. The sun 

 dance was. a most elaborate religious ceremony, in 

 which the sun symbolised the Divine Power. It lasted 

 several days, and, besides the complex ritual involved 

 in the raising of the Sacred Pole and other ob- 

 servances, the leading feature Avas the self-infliction 

 of bodily torture by the participants as a sacrifice to 

 their deity. In the most severe forms this involved 

 suspending the bodies of the willing victims by 

 skewers and thongs driven through their flesh in the 

 fierce heat of the sun until the victims tore them- 

 selves down, lacerating their flesh in the process. In 

 addition, the whole of the assembly would go without 

 food and drink for several days during this period. 

 Each phase of the ritual had its special song. The 

 natives even now deplore the substitution of the white 

 man's religion and education for what they regarded 

 as a discipline in heroism and bravery. It is stated 

 that boys used to go through a miniature copy of the 

 ritual in which they aspired to participate when of 

 adult age. 



Another group of songs is associated with certain 

 societies existing in the tribe. Some of these, called 

 Dream Societies, are constituted of individuals who 

 are distinguished by the particular animals which 

 appeared to them in dreams, such as the badger, 

 buffalo, or elk; others were oif a military character. 



The only musical instrument which figures in most 

 of these songs was the drum, which was of the usual 

 type, but in the sun dance a stiff rawhide was also 

 beaten. The author also refers very briefly to two 

 whistles, one of bone used in the sun dance, the other 

 of wood used in grass dances, which latter is capable 

 of emitting a series of harmonics. 



The tone-scale of the songs approximates to the 

 well-known five-tone scale represented by the black 

 keys of the piano, but the intervals are in reality a 

 little different. A noticeable feature is a more or less 

 marked resemblance to some of our present "modern " 

 music, both in the absence of well-defined melody and 

 in the irregularity of the rhythm. A few of the songs, 

 indeed, do appear to possess something in the nature 

 of a tune in them ; in others the sequence of notes is 

 very much of the same chaotic character that is so 

 conspicuous at modern recitals. Again, in the rhythm 

 one bar is often in three-time and the next in four — an 

 artifice which Brahms knew how to use with good 

 effect, but which is now commonly employed in order 

 to render music unlovely, and therefore what is de- 

 scribed as " thrilling." Again, the voice part is fre- 

 quently independent of the drum rhythm, the latter 

 beintr usuallv in more regular time. It mig'ht thus 

 be possible that if suitable harmonics, or rather dis- 

 cords, were added, these song's might appeal to the 

 class of present-day concert-goers who appreciate the 

 attempts of modern pianists to represent " Le Raid 

 des Zeppelins." 



What, however, is much more important is the 

 glimpse which this unique collection affords of the 

 hichlv complex system of primitive poetic and musical 

 art that this tribe of American Indians had built up. 

 which is fast becoming obsolete under the social 

 and educational influences brought into force by the 

 v'hite race?. G. H. Bryan. 



ELECTRICAL PURIFICATION OF CLAYS. 

 'T^HE phenomena known as electrical endosmose 

 ^ and cataphoresis, whereby matter in a verv finely 

 divided or colloidal state is capable of being influenced 

 by an electrical potential, have been extensively 

 investigated. For instance, when a colloidal solution 

 of arsenious sulphide is placed in a cell and a direct 

 current at a potential of 100 volts passed from 

 suitable electrodes through the solution, the colloidal 

 particles tend after a time to collect round the positive 

 pole, leaving a clear zone round the negative pole. 



It is found that nearly all substances, if in a 

 sufficiently fine state of division, are attracted either 

 to one pole or the other. It has also been observed 

 that aggregates of certain fine particles can be dis- 

 persed and separated by adding to the fluid in which 

 they are suspended minute quantities of alkali in 

 the case of those particles attracted to the positive 

 pole, and of acid to those which are attracted to the 

 negative pole. Moreover, if the particles are not 

 sufficiently susceptible to the dispersive effect of the 

 added electrolyte, they can be made so by being 

 allowed to adsorb some colloid, such as colloidal silicic 

 acid. 



This latter discovery has a most important bearing 

 on the clay industry. China clay and ball clay are 

 examples of such aggregates of fine particles, and if 

 a thick slip is made up of the clay and water the 

 addition of small amounts of alkali causes the clay 

 particles to disperse, and the slip, as a consequence, 

 to become much thinner and more mobile, the clay 

 particles remaining in suspension a considerable time 

 and exhibiting vigorous Brownian movement. On 

 passing a current of electricity through such a sus- 

 pension, the clay particles collect and adhere closely 

 to the anode plate, the water collecting in a zone, 

 substantially free from clay, round the cathode. Im- 

 purities in the original clay, such as mica, quartz, 

 felspar, and iron compounds, are either unaffected by 

 the electrical potential and settle out, or attracted 

 to the cathode. A means of purifying clay on a com- 

 mercial scale can thus be evolved from a consideration 

 of the above phenomena, as was shown by the exhibit 

 of raw and purified clays of the Osmosis Co., Ltd., 

 at the recent British Scientific Products Exhibition. 



The commercial equipment for such a process con- 

 sists of a blunger, settling tanks to allow the coarse 

 impurities to settle out of the suspension, and an 

 Osmosis machine composed of a rectangular trough 

 in which is arranged horizontally a cylindrical metal 

 anode surrounded beneath the surface of the slip 

 and at a short distance away from it by a cathode 

 through which, by paddles or other means of cir- 

 culation, the clay slip is driven. The cylinder is made 

 to revolve slowly, and by means of a scraper the dried 

 purified clay, containing 20-30 per cent, of water, is 

 collected. 



The machine not merely collects the suspended clay 

 and frees it from water, but subjects the suspen- 

 sion to an electrical purification as well, for should 

 there still be in suspension with the clay minute par- 

 ticles of mica, iron, and silica that have not had time 

 to settle out in the tank, these are not attracted to the 

 anode, but for the most part remain in the effluent 

 leaving the trough. Consequently, electrically osmosed 

 clav is a purer product than can be obtained by any 

 method of settling or centrifuging. 



The improvements effected by the process are : — 

 (i) Pvritic and other forms of uncombined iron are 

 removed. (2) The sintering temperature of the clay 

 is lowered so that a lower kiln-temperature can be 

 employed, with consequent saving of fuel. (1) Clay 

 can be graded into different degrees of fineness. 



NO. 2600, VOL. 103] 



