February 7, 19 18] 



NATURE 



451 



be aware of the work of W. A. Davis (Nature, 1912, \ 

 vol. xc, p. 441), who established most of the above '\ 

 facts, and in addition showed that the loss of potass- 

 ium perchlorate can be entirely obviated by washing 

 with alcohol saturated with this salt. 



Mr. Robinson Smith, in an article on eificiency in 

 the Quarterly Review, states that the two forces in 

 America that in recent years have done most to put the 

 American house in order, and of which next to nothing 

 is known in Europe, are efficiency and prohibition. 

 Efficiency, or scientific management, as it was termed 

 by its founder, was introduced by Mr. F. W. Taylor, 

 and its methods certainly lead to large increases in the 

 output per worker. Mr. Taylor got his data by timing 

 men at work with a stop-watch, and by seeing whether 

 the men could do more work if they omitted certain 

 movements or rested periodically ; hence the term 

 " motion-study." The following illustrates the process 

 applied to a gang of men lifting pig-iron from a 

 ground-pile, walking up an inclined plank, and drop- 

 ping it into a car at the rate of 12J long tons per day. 

 "Taylor's first step was to single out one of these men 

 — of the ox-type of man — and on this first day and all 

 day long he was told by the man who stood over him 

 with a watch : ' Now pick up a pig and walk '; ' Now 

 sit down and rest,' and at half-past five in the after- 

 noon the man had loaded 47^ tons of pig-iron on to 

 the car." The author of the article expresses regret 

 at the cold reception which has been given to Mr. 

 Tavlor's ideas in Britain, and uses many arguments 

 in its favour. Probably the prejudices which bar the 

 wav at present would be modified considerably if work- 

 men were convinced that better wages and shorter 

 working hours would permanently follow the introduc- 

 tion of Mr. Taylor's methods. 



" Some recent developments in balancing apparatus 

 are described in a paper read by Mr. N. W. Akimoff 

 before the American Society of Mechanical Engineers 

 and reprinted in Engineering for February i. Mr. 

 Akimoff 's original machine consisted in principle in 

 mounting the body which required dynamic balance on 

 a beam hinged at one end and supported on a 

 spring at the other. A "balancing cage" was also 

 mounted on the beam and rotated in unison with the 

 body. By moving masses on the balancing cage, the 

 effect of the rocking couple on the body was neutral- 

 ised, and from a knowledge of the amount and position 

 of these masses was obtained the information neces- 

 sary to correct the want of balance in the body. In 

 Mr". .\kimoff's latest machine the effects of both static 

 and dynamic want of balance can be readily neutralised 

 bv means of a clamp fixed to the body, and having a 

 mass which can be adjusted in radius from the axis of 

 rotation. The clamp can be moved axially and also 

 adjusted for angular position. The effect of static 

 want of balance is first eliminated, and the rocking 

 couple is then got rid of. The machine is ingenious, 

 and appears to be effective in solving a rather trouble- 

 some problem. 



The water supply of the city of Brisbane is the sub- 

 ject of an article in the issue of the Engineer for 

 January 25, and the following particulars are of in- 

 terest. The supply is derived chiefly^ from the Bris- 

 bane River. The pumping plant, which is located 

 about twenty miles from the city, and above the tidal 

 region, consists of three triple-expansion, condensing 

 engines, each capable of pumping six million gallons 

 per twenty-four hours. The population supplied is 

 about 158,000, and the average daily consumption forty- 

 six gallons f>er head. There is an important storage 

 reservoir at Cabbage Tree Creek, a tributary of the 

 Brisbane River, formed by a dam of cyclopean con- 



NO. 2519, VOL. 100] 



Crete, 740 ft. long (including the by-wash), 125 ft. 

 high, 95 ft. thick at the base, and 10 ft. wide at the 

 top. The surface area of the enclosed lake is 

 700 acres, and the quantity of water impounded 

 5,800,000,000 gallons. The rainfall of the district is 

 intermittent; there are long periods of drought alter- 

 nating with heavy downfalls, which result in floods. 

 The longest recorded period of drought was in 1915, 

 when the Brisbane River was dry for eight weeks. 

 Allowing for evaporation, the available quantity of 

 water, when the reservoir is full, affords 12,000,000 

 gallons daily for 300 days, and as the present con- 

 sumption" is only seven and three-quarter million 

 gallons per day, there is ample margin for consider- 

 ably more than a year's supply without the aid of a 

 single drop of rainfall. The dam was ceremonially 

 opened in December, 19 16, the work having cost about 

 172,000^. 



The latest catalogue of second-hand books (No. 172) 

 just issued by Messrs. W. Heffer and Sons, Ltd., Cam- 

 bridge, should be of much interest to readers of 

 Nature, seeing that it deals mainly with books relat- 

 ing to science. It contains sections devoted to astro- 

 nomy and meteorology, botany (including forestry and 

 herbal), chemistry, folklore and mythology, geology, 

 mineralogy and palaeontology, mathematics, physics 

 and engineering, physiology, anatomy and medicine, 

 and zoology, biology and Nature-study. Copies of the 

 catalogue are obtainable upon application. 



OUR ASTRONOMICAL COLUMN. 



Luminositiks and Parallaxes of 500 Stars. — The 

 spectroscopic method of determining the absolute mag- 

 nitudes, and thence the luminosities and parallaxes, of 

 stars has been further improved in detail by Messrs. 

 W. Adams and A. H. Joy, and applied to 500 stars 

 {Astrophysical Journal, vol. xlvi., p. 313). For stars 

 of the same spectral type, the enhanced lines and the 

 hydrogen lines are relatively strong in those of high 

 luminosity, and v^eak in those of low luminosity, while 

 the low-temperature lines behave in a manner directly 

 opposite. For 360 of the stars, measured parallaxes 

 are available for comparison, and the average difference 

 between these and the spectroscopic parallaxes, taken 

 without regard to sign, is 0-026*. The spectral types 

 now within the capacity of the spectroscopic method 

 range from AS to M. One of the most striking con- 

 clusions from this important investigation is that the 

 distinction between "giant" and "dwarf" stars is 

 clearly shown for types M, K, and G, with a slight 

 indication of such separation even in the case of F 

 stars. In the case of the M type the list includes 

 thirty stars brighter than absolute magnitude 39, and 

 twelve stars fainter than absolute magnitude 95, with 

 none of intermediate brightness. It is considered 

 almost certain, in the case of types M and K at least, 

 that these results cannot be ascribed to the selection 

 of the stars. The catalogue is conveniently arranged, 

 and includes position, proper motion, and visual mag- 

 nitude, besides other data. 



Solar Hydrogen Bombs. — A remarkable solar 

 phenomenon of short duration has been investigated 

 photographically and visually by Mr. F. EUerman at the 

 Mt. Wilson Observatory (Astrophysical Journal, vol. 

 xlvi., p. 298). It consists of the sudden appearance 

 of a very brilliant narrow band extending for several 

 angstroms on each side of Ha, which persists as a 

 dark line with little change in width. The duration is 

 only from one to three minutes on the average, and 

 rarely from five to ten minutes. The average width 

 of the bright band is about 8 A., but in an extreme 

 case the band extended over 30 A. These "bombs" 



