February i6, 1893 



NA 7 URE 



79 



5. The numerous attendants of the old steam engines and 

 boilers have mostly been transferred to other work, only a few 

 •f them are required at the central station, and one or two men 

 can easily look after all the electric motors used in the various 

 parts of the works. 



Elsewhere equally favourable results have been obtained by 

 the introduction of electrical distribution of power, and in this 

 respect I beg to refer you to a paper read before the German 

 Institution of Civil Engineers by Mr. E. Hartmann in April of 

 last year, and to a paper read by Mr. Castermans before the 

 Society of Engineers in Liege, in August last, in which he 

 compares in detail various methods of transmission of power, of 

 which the electrical one was adopted for a new small arms 

 factory. 



We may therefore take it for granted that the advantages 

 alluded to above have not resulted from local circumstances at 

 Woolwich, but that they can be realised anywhere by the adop- 

 tion of the electric current for distributing power from a central 

 station. 



At first sight this result appears to be of interest only to the 

 manufacturer ; but the development of this idea may lead to 

 far-reaching consequences, when we consider that cheap power 

 is one of the most important requisites for cheap production. 



While power was generated by steam engines the cost of 

 producing one-horse-power varied a good deal in the different 

 parts, and the various owners could not have obtained their 

 power on equal terms, those possessing the largest steam 

 engines having a distinct advantage. This inequality is done 

 away with altogether when the power is distributed by elec- 

 tricity, as the current can be supplied for large or small powers 

 at the same rate per Board of Trade unit. It is therefore 

 clear that the establishment of central stations for the generation 

 of electricity on a large scale will bring about the possibility of 

 small works competing with large works in quite a number of 

 trades where cheap power is the first consideration. 



Another circumstance favouring small works is the diminution 

 of capital outlay brought about by the employment of electric 

 motors. Not only are the motors cheaper than boilers and 

 steam engines of corresponding power would be, but the outlay 

 for belting and shafts is saved, and the structure of the building 

 need not be as substantial as is necessary where belts and shaft- 

 ing have to be supported by it. A commencement has already 

 been made in this direction by the starting of electric light 

 stations, where the owners do all in their power to encourage 

 the use of the current in motors, in order to keep the machinery 

 at their central station more uniformly at work. The intro- 

 duction of electricity as motive power will apparently present a 

 strong contrast to the effect steam has had on the development 

 of industries for the reasons already stated ; and in addition 

 there are many cases where the erection of boilers and steam 

 engines, or even of gas engines, would be inadmissible on 

 account of want of space or of the nuisances that are inseparable 

 from them. Motive power will therefore be available in a 

 number of instances where up to the present time no mechanical 

 power could be used, but the work had to be done by manual 

 labour or not at all. 



You may have noticed that I have confined my remarks 

 hitherto to the case of distributing electricity over a limited area, 

 but that I have not yet discussed the question of transmitting 

 power to a great distance. 



Theoretically we have been told over and over again that the 

 motive power of the future will be supplied by waterfalls, and 

 that their power can be made available over large areas by 

 means of electric currents. As a prominent example the in- 

 stallation is constantly mentioned by which the power of a 

 turbine at Lauffen was transmitted over a distance of i lo statute 

 miles to the Frankfurt Exhibition with an efficiency of 75 per 

 cent. No doubt this result is very gratifying from a purely 

 scientific point of view, but unfortunately in practical life only 

 commercially successful applications of science will have a lasting 

 influence, and in this respect the Lauffen installation left much 

 to be desired. On the one hand science tells us that the section 

 of the conductor can be diminished as the pressure of electricity 

 is increased, and it appears to be only necessary to construct 

 apparatus for generating electricity at a sufficiently high pressure 

 so as to reduce the cost of a long conductor to reasonable limits. 

 On the other hand, experience shows that at these high potentials 

 the insulation of the electric current becomes a most difficult 

 problem, and for practical purposes difficulty means an increased 

 outlay of money. 



NO. 12 16, VOL. 47] 



MAGNETJCAL AND METEOROLOGICAL OB- 

 SER 1 'A TIOXS MADE A T THE GO VERNMENT 

 OBSERVATORY, BOMBAY, 1890, WITH AN 

 APPENDIX. 



'X'HIS volume, we are informed, is the thirtieth of the series 

 of " Bombay Magnetical and Meteorological Observa- 

 tions," extending the previous record from 1845 to 1889, up to 

 1890. At this well-organized observatory, under the direction 

 of Mr. Charles Chambers, continuous registration of the different 

 magnetical and meteorological elements is maintained by means 

 of automatic recording instruments, of which there are five sets, 

 the magnetographs (three), the barograph, the thermograph, the 

 pluviograph, and the anemograph, all being photographic records 

 excepting that of the anemograph, which is mechanical. In 

 addition eye observations are also made, including the usual 

 meteorological observations of weather and other phenomena. 

 j Daily values for 1890 are given of atmospheric pressure, tem- 

 I perature of the air, rainfall, wind and cloud, with some further 

 I discussion of the anemometric results ; five day means of meteoro- 

 \ logical elements are also given. In the magnetic section is 

 j found observations of absolute horizontal force, magnetic decli- 

 j nation and dip, at short intervals throughout the year. And in 

 I the appendix is contained a collection of the monthly values of 

 j declination and horizontal force from 1868 to 1890, accompanied 

 by a discussion of the secular changes of these elements. In 

 regard to declination the results show the eastern magnetic 

 declination to have increased during the early years of the series, 

 arriving at a maximum at about the middle of the period, and 

 decreasing in the later years. Taking the annual values of 

 declination to be represented by the formula S-=ai- + di + c, it is 

 found that the maximum easterly declination occurred in 1880, 

 with value 0° 57' 17". This actual observation of the turning- 

 point at this place, in the long cycle of change, is very interest- 

 ing. The horizontal force values are similarly discussed, but in 

 this case the values are generally progressive. There is no dis- 

 cussion of diurnal inequalities, but these were elaborately treated 

 in a previous volume. Magnetic observatories in tropical and 

 southern regions are valuable. Many exist in Europe with others 

 scattered over different parts of the northern hemisphere.generally 

 publishing with regularity their results, but there is a want of 

 similar establishments in southern regions. There are magnetic 

 observatories at Batavia, Mauritius, and Melbourne, but we do not 

 get from them all that might be desired. England possesses no 

 regularly maintained southern establishment of this kind. A 

 magnetic observatory existed many years ago at the Cape of Good 

 Hope, which, long since destroyed, we believe, by fire, was 

 never again reorganized, which was unfortunate. The attention 

 of the Magnetic Committee of the British Association was several 

 years ago drawn to the question of re-establishing the Cape Mag- 

 netic Observatory, and in the Report of the Committee for the 

 year 1 891 it is stated that a representation had been made to the 

 Admiralty as to the desirability of so doing. An efficient mag- 

 netic observatory in such a position, with regular publication of 

 the results, would provide information of great value for the 

 discussion of various questions in magnetic phenomena that now 

 arise. It would be well also if the study of earth currents were 

 taken up at some of the magnetic observatories in different parts 

 of the world by continuous photographic registration thereof, 

 for the better elucidation of the physical relation that may exist 

 between magnetic and earth current variations, in regard to 

 which our knowledge seems at present to be so imperfect. 



BACTERIA AND BEER. 



T^HE examination of water for micro-organisms since the pub- 

 ■*■ lication by Koch in 1881 of his beautiful process of gelatine- 

 plate cultures has come more and more into general use, as the 

 public has gradually become cognisant of its value for hygienic 

 and practical purposes. But whilst affording much valuable infor- 

 mation on many subjects, Hansen has pointed out, as far back a.'i 

 1888, that as applied to the examination of waters for brewing 

 purposes it connot be considered wholly satisfactory. Working 

 on lines suggested ly Hansen, Holm has recently published a 

 paper, " Analyses biologiques et zymotechniques de I'eau des- 

 tinee aux brasseries " {Compte-revdu des travaux dii laboratoire 

 de Carlsberg, vol. iii., Copenhagen, 1892), in which he describes 

 a large number of investigations on brewing-waters examined by 

 Hansen's method, and in which the relative merit for brewing 



