May 24, 19 1 7] 



NATURE 



2^1 



testinal amoebae of man. They point out that diver- 

 gent views exist as to (a) the differentiation of species 

 of intestinal amoebae, (b) the pathogenicity of the 

 different species, and (c) the differentiation of species 

 when encysted. They state their principal conclusions 

 as follows : Entamoeba letragcna is usually regarded 

 as identical with E. histolytica, and our results con- 

 firm this view. E. minuta is usually regarded as the 

 pre-cyst of E. histolytica, whereas we have found 

 minuta forms associated with both E. coli and E. 

 histolytica. Where the prevalent type of organism 

 was E. minuta it was commonly in association with 

 8-nucleate cysts, and resembled E. coli. We believe 

 that these "different species" are all one and the 

 same organism. The paper is illustrated with two 

 excellent coloured plates. 



The method of measuring a small electric current, 

 as, for example, the ionisation current through a gas, 

 by the rate of leak of 'he charge on an electrometer 

 through a known high resistance, has proved so 

 convenient that many experimenters will welcome a 

 paper by Dr. W, F. G. Swann and Mr. S. J. Mauchly 

 on a method of constructing a high resistance of the 

 Bronson type, for which Ohm's law is applicable, 

 which appears in the March number of Terrestrial 

 Magnetism and Atmospheric Electricity. A small 

 quantity of ionium, which was chosen as the most 

 suitable radio-active material, is placed in a shallow 

 -depression in the upp>er face of a brass plate and 

 covered with sheets of mica and silver foil. The plate 

 rests on the bottom of the ionisation chamber, through 

 the top of which an insulated tube carr\'ing a circular 

 electrode projects. Through this tube a rod passes 

 which carries a smaller plate, and the distances of 

 both plates above the ionium plate can be varied. 

 The metal surfaces within the chamber are all silver- 

 plated. When the upper plate is 46 cm. and the lower 

 I cm. above the ionium plate, the resistance of the 

 cell is constant up to a potential difference of .4 volts, 

 owing to the usual decrease of conductivity being 

 compensated by the action of the 8 rays from' the 

 metal surfaces. 



In the adoption of any scheme which runs counter to 

 habits and prejudices, and with which obvious advan- 

 tages and disadvantages are connected, as in the sub- 

 stitution of " Summer Time " for the normal and uni- 

 form method of time reckoning, many suggestions 

 will be made wuth the view of improving the 

 mechanism and diminishing the inconveniences. M. 

 Desortiaux, of Tulle, a retired French engineer, is 

 early in the field with a pamphlet, "La R^forme 

 rationnelle de I'heure" (Gauthier, Villars), urging some 

 drastic proposals that seem calculated to make con- 

 fusion worse confounded. He objects to the abrupt 

 alteration of the clock-hands twice a year, involving 

 sudden interruptions of time-reckoning, and recom- 

 mends a number of small alterations, the maximum 

 being seven minutes, which he thinks could be intro- 

 duced imperceptibly and without dislocation of our 

 liabits, by arrangement with the railways and other 

 public indicators of time. In each week of January 

 the clock is to be advanced five minutes. On two 

 •days of each week in February, April, and May the 

 clock will be accelerated six minutes, and in March 

 seven minutes. In June there will be no alteration, 

 and in the second half of the year there will be re- 

 tardations of similar amount, to restore the clock time 

 to normal condition in January. The alteration effected 

 by these small increments is far more considerable 

 than in the plan that has obtained legislative sanction. 

 The accumulative effect at maximum is 3-57 hours, 



NO. 2482, VOL. 99] 



one object of the ingenious proposer being to make 

 the watch indicate approximately the same hour at 

 sunrise. This arrangement discloses one weakness of 

 the plan. It takes no account of latitude, and though 

 the author admits the necessity of agreement between 

 countries that have conterminous borders, he does not 

 consider that the inhabitants on the Belgian border 

 would be differently affected from those on the Italian. 

 Again, it is strange that one who clearly perceives the 

 annoyance caused by the sudden change of an hour, 

 with its tendency to disarrange transport services, can 

 suppose that a long-suffering public would endure a 

 series of irritating interruptions twice a week for 

 many months of the year. But having sanctioned a 

 tampering with the uniform record of time, many 

 utterly impracticable methods will be proposed with 

 the benevolent intention of reducing the inconvenience 

 to a minimum. 



In the April issue of the Quarterly Review will be 

 found a well-informed article by Prof. W. J. Ashley on 

 German iron and steel treated from the point of view 

 of its commercial as distinct from its technical develop- 

 ment. The syndication movement in Germany began 

 to achieve continuous and substantial success when in 

 1892 the pig-iron producers came together, and in 1893 

 the Westphalian Coal Syndicate was formed. ITiis 

 example was followed by various branches of the steel 

 trade. These combinations began with a mere price 

 agreement; then thev had to apportion the sale; and 

 afterwards they concentrated the marketing of their 

 commodity in a^common selling organisation. Prof. 

 Ashley then traces the further development of these 

 "cartels" and their amalgamation into the " Stahl- 

 werksverband," the great Steel Syndicate, which has 

 commanded the whole position ever since. In order 

 effectively to regulate price it limits each of the con- 

 stituent concerns to a prescribed quota of a defined 

 total output and concentrates all the sales in a central 

 office. The growing cost of plant makes it very diffi- 

 cult for new competitors to start up from outside. In 

 Germany the experts consider that no new steel works 

 can profitably be put down which have an output 

 capacity of less than 400,000 tons. Finally, the system 

 of bounties payable to home manufacturers in respect 

 of their export trade is explained. 



The formation of " ground ice," or " anchor ice," at 

 the bottom of running streams occurs sometimes in 

 this country, and forms the subject of an article in 

 Engineering for May 11, by Mr. J. MacAlister, assist- 

 ant engineer at the Greenock Waterworks. Ground 

 ice has been experienced at Greenock in the "Cut," an 

 open aqueduct some five miles long and situated about 

 500 ft. above sea-level. The water has a velocit>' of 

 about 3 ft. per second, and ice sometimes forms at 

 the bottom, thereby raising the surface-level of the 

 water. Careful watching is required, as the slabs of 

 ice sometimes take up such positions during the process 

 of release as lead to overflow of the water. Despite 

 other theories. Mr. MacAlister is inclined to think that 

 the formation of ground ice in this channel, which 

 has a rough bottom, is due to the cooling of the whole 

 mass of water and the ice first forming in the com- 

 paratively still wate- encountered in the lee of stones, 

 etc. The process may be, and probably is, accelerated 

 by radiation, as the portions of the aqueduct where the 

 ice usually forms first are situated at comparativelv 

 open spaces, and have low banks. Towards the end 

 of January this year, for the first time in the history 

 of some of the reservoirs, the formation of ground 

 ice was general throughout the Greenock Waterworks. 

 The author describes the various measures taken to 

 remove the consequent ice blockages. 



