October 5, 1893] 



NA TUKE 



557 



electrical engineering, and not physics, should be treated upon. 

 The author said that until recently, electrical machines for the 

 transmission of power were of the continuous current type, but 

 lately alternate current apparatus had come into use, chiefly 

 because the power could be carried to greater distances with a 

 moderate cost of conductors. The reason for this was that with 

 continuous current plant the voltage is limited by the difiGculty 

 of insulating the generating machinery. With alternate current 

 there is no necessity of high insulation of generator or motor, 

 but only of the transformers, which can be easily insulated by 

 the use of oil or other means. The author dealt with five sys- 

 tems of transmission. 



(i) Single phase alternating current transmission by two wires. 

 (2) Double ,, ,, ,, ,, ,, four ,, 



il) .. >> ., >> ,1 .. three,, 



(4) Three ,, ,, ,, ,, „ three „ 



(?) Continuous current with transmission by two wires. 



We have not space to follow Mr. Kapp's ingenious reasoning, 

 but will briefly give his conclusions. If all systems were put on 

 the same footing as regards efficiency and safety of insulation, 

 tlie following results would be obtained. If, for the transmission 

 •of a certain power over a given distance by continuous current, 

 100 tons of copper were required for the line, then the single 

 phase alternating and the two phase four wire system would 

 require 200 tons. The two phase three wire system would 

 require 290 tons, and the three phase three wire system only 150 

 tons ; therefore, so far as the line might be concerned, there 

 would be a distinct advantage in the employment of the three 

 phase system. 



A paper by Mr. A. B. Snell, " On Water Power as a Source 

 of Electricity," was next read. The subject is not one of such 

 great practical importance in England as in more mountainous 

 countries. Our rivers are small, and in comparatively few cases 

 is there sufficient head to make the utilisation of them profitable 

 with such a form of water motors as have yet been introduced. 

 Mr. Beaumont described a variable power gear for electrical 

 locomotives which he had devised. The object of the gear is 

 to give increased power for the motor when starting the train. 

 By its use the designer hoped that electric motors might be made 

 of very much smaller size. A point of interest raised during 

 the discussion was the advisability of using epicycloidal gear, it 

 being the opinion of Prof. Hele Shaw and others who had worked 

 with this gear that it was not suitable for heavy loads. Mr. 

 W. B. Sayers read an interesting and valuable paper, in which 

 he described a form of self-exciting armature and compensator 

 for loss of pressure, which he had devised. The invention is 

 one of considerable importance, the object being to obtain 

 sparkless commutation. The device, however, is not quite new, 

 it having been previously described, and doubtless is known to 

 the majority of our electrical readers. Monday's proceedings 

 closed with a paper by Mr.E. Payne, on "Electrical Conductors." 



Tuesday, September 19, was the last day on which Section G 

 met, and the proceedings opened with a paper by Mr. O. T. 

 Olson, on " Flashing Lights for Marine Purposes." The author 

 proposed that each important navigational light in the world 

 ^ould have a distinctive number which it should continuously 

 flash at night, so that there might be no danger of any particular 

 tight being mistaken by the mariner for another. During fog 

 the signals were to be conveyed by gun-cotton explosion. Pro- 

 bably Mr. Olson's suggested signals are somewhat too com- 

 plicated, although possibly as simple as could be practically ar- 

 ranged were every light given a separate number. Nevertheless, 

 something might be done towards systematising the signals given 

 by various lights in certain geographical sections. 



Mr. William S. I.ockhart gave an interesting description of 

 an automatic gem separator which he had devised. The ap- 

 paratus acts by means of the difference in specific gravity 

 between the gems and the gravel, quartz, &c. , in which they are 

 found. A stream of water flowing at a uniform velocity is 

 •directed upwards through an annular chamber. The material 

 to be separated is fed in through a hopper at the top of the 

 apparatus, and falls into the annular chamber. The velocity of 

 the stream is so regulated that the lighter and more worthless 

 substances are carried with it, whilst the heavier gems descend 

 into a receptacle at the bottom of the machine. One of the 

 separators was shown at work in the Section, water being laid 

 on for the purpose, and some diamonds were actually separated 

 from the pebble and quartz with which they were mixed. There 

 are, it is hardly necessary to say, many points in detail which 



NO. 1 249, VOL. 48] 



require careful consideration in working out before such a 

 machine as this is brought to the perfection of practical work- 

 ing. Mr. Lockhart appears to have been very successful in over, 

 coming the difficulties of the problem he had to solve in designing 

 the machine. 



A paper by Mr. Walker, " On Ventilating Fans," was read, 

 and the proceedings in this Section closed by Prof. Robinson 

 describing the Wicksteed testing machine, which had been 

 erected in the engineering laboratory of the college. The mem- 

 bers of the Section were able to see this machine in action 

 during the afternoon. In most respects it does not differ from 

 the ordinary type of Wicksteed testing machine, but there is a 

 clever gear for .shifting the poise. This was operated by hydraulic 

 power by means of wire rope. The device is undoubtedly an 

 improvement on the old gear, both in rapidity of action and 

 absence of noise. There is a neat parallel adjustment for pre- 

 venting the pulley of the rope influencing the result of the test. 



The proceedings in Section G were brought to a conclusion 

 by the usual vote of thanks to the sectional president, Mr. 

 Jeremiah Head. 



ANTHROPOLOGY AT THE BRITISH 

 ASSOCIATION. 



A FTER the President's address on Thursday, Mrs. Lilly 

 Grove read a paper on the ethnographic aspect of dancing. 

 Dancing corresponds to a universal primitive instinct in man. 

 At all periods there were three kinds of dances : (l) the 

 imaginative or poetic ; (2) the descriptive ; (3) the religious. 

 This last is most important, and may be called the fountain of 

 the other kinds. Religious dances can be divided into two classes: 

 (a) dances directly in honour of the deity ; {b) dances intended 

 to propitiate the deity. A strange feature is the fact that so 

 many dances are performed in a circle. War-dances are of two 

 orders, either as a preparation for war, or as a rejoicing after 

 triumph. The Corroboree illustrates the former aspect. Ex- 

 cellence in dancing among savages is obtained by very simple 

 means : anyone who makes a mistake is killed. 



Prof. Windle read a paper on anthropometric work in schools. 

 It appears from answers to a circular sent to the head-masters of 

 one hundred of the largest schools in the United Kingdom, that 

 some form of measurement is or has been carried on in twenty- 

 five schools, but that the methods adopted differ considerably. 

 The author suggested that an endeavour should be made to 

 encourage and systematise such work. 



Dr. W. Wilbevforce Smith read a paper on anthropometric 

 weighing ; and the following reports were also presented to 

 the section : Report of the Anthropometric Laboratory Com- 

 mittee, and Report of the Physical Deviations Committee. 



On Friday, the committee appointed to make an ethno- 

 graphical survey of the United Kingdom presented their first 

 report. Prof. Hans Hildebrand then read an important paper on 

 Anglo-Saxon remains and coeval relics from Scandinavia. The 

 question proposed was to determine the relations which 

 existed between the civilisation of Scandinavia and that of 

 England during the period between the arrival of the Angles 

 and the Saxons on the English coast, and the time of their con- 

 version to Christianity ; roughly, that was from the middle of the 

 fifth to the middle of the seventh century of our era. These limits 

 were not exactly determinable, because both the Anglo-Saxon 

 immigration and the spread of Christianity among the new- 

 comers were not the work of a few years only, and progressed 

 with very different rapidity in different parts of the country. 

 During tbis period Sweden had no chronological record, and 

 Christianity had no hold on that country until the eleventh cen- 

 tury. The criterions of date, therefore, on the Scandinavian 

 side were of purely archreological character. There were a few 

 instances of Roman and Byzantine coins found associated with 

 Scandinavian antiquities, and as these could hardly have found 

 their way northward before the downfall of the Hunic Empire 

 in Central Europe, they gave some indication of the date of the 

 objects with which they were lost or interred. In England 

 similar date evidence occurred, but was vitiated by the fact that 

 the coins had often been long in circulation before they were 

 buried. The practice of burial also, while it entirely super- 

 seded cremation when Christianity became predominant, ap- 

 peared to have coexisted with the older method during the later 

 Pagan period, and could not be taken as affording an accurate 

 criterion of age. 



And there was the further difficulty in comparing English and 



