358 



NATURE 



[June 28, 1917 



(5) There cannot be too many highly trained appren- 

 tices. (6) Special training must be given to those 

 apprentices who show marked ability. The article is 

 very interesting to all concerned in the training of 

 apprentices, and throws light on one reason for the 

 success of the well-known firm mentioned. 



Prof. Ignazio Galli has an article, "Sulla questione 

 della lingua internazionale," in a recent number of 

 the Aiti della Pontificid Accademia l^omana dei Nuovi 

 Lined. Among arguments in favour of a common 

 international language he lays stress on its conveni- 

 ence at scientific congresses. Those who attend such 

 meetings must have noticed that when each member 

 uses his own language the discussion often shows 

 that a speaker has imperfectly understood much that 

 has been said in a language foreign to him. As 

 regards the choice of the international language, 

 Prof. Galli finds that Volapiik is too complicated and 

 difficult to pronounce. Esperanto is easy to pro- 

 nounce, since it gives to each letter of the alphabet 

 only one sound. Prof. Galli thinks that the belief 

 that Esperanto would become a universal language is 

 steadily losing ground, and that this is due to its too 

 artificial simplicitv, which renders this language 

 meagre and rather vague. We are told that Ido has 

 a more rational selection of words than Esperanto, 

 while Simplo, a language invented by Mario Ferranti, 

 has about 5800 words, which are formed from roots 

 common to Latin, Italian, French, and English. 

 Finding none of these artificial languages to be suffi- 

 ciently flexible to express all the ideas of modern 

 science and philosophy. Prof. Galli strongly urges that 

 instead of wasting energy in the creation of a new 

 language, Latin should be adopted as a common 

 language for international intercourse. He proposes 

 that Latin should be taught in schools, not as a dead, 

 but as a living, language. Men of all nations would 

 then converse freelv when they met, as the learned 

 could in the days of Roger Bacon. In connection with 

 Prof. Galli 's sup-q-estion, it is worth while to mention 

 that Latin and Greek are both taught as living lan- 

 guages at the Perse School, Cambridge, with very 

 successful results. A letter on "Latin as a Universal 

 Language," by the late Sir Lauder Brunton, appeared 

 in Nature of February 10, 1916 (vol. xcvi., p. 649). 



SOCIETIES AND ACADEMIES. 

 London. 

 Royal Society, June 14. — Sir J. J. Thomson, presi- 

 dent, in the chair. — Prof. T. H. Havelock : Some cases 

 of wave motion due to a submerged obstacle. In Lliis 

 paper Prof. Lamb's solution for a submerged circular 

 cylinder is carried a stage further in the approxima- 

 tion, and the wave resistance is calculated directly 

 from the resultant fluid pressure on the cylinder. 

 Similar methods are then applied to a three-dimen- 

 sional problem, the waves produced by a submerged 

 sphere. — Prof. L. V. King : The propagation of sound 

 in the free atmosphere and the acoustic efficiency of 

 fog-signal machinery. — H. J. Shannon, F. F. Renwick, 

 and B. V. Storr : The behaviour of scattering media 

 in fully diffused light. The paper deals with the 

 relationships between the rejectance (proportion of in- 

 cident light rejected), the obstruction (ratio ol incident 

 light to transmitted light), light capacity (ratio of 

 accepted light to transmitted light) when a sheet of 

 diffusing medium is illuminated .on one side by diffuse 

 light, and also the relative oBstruction, and relative 

 density, when, as in various instruments, the source 

 of light is a first sheet of diffusing medium in contact 

 with the sheet being examined. The experimental 

 part of the paper discusses the method of using the 



NO. 2487, VOL. 99] 



theoretical equations obtained for determining the con- 

 stants of a specimen of diffusing medium, certain 

 requirements of the instrument used, and precautions 

 to be taken. Examples are given showing the close 

 agreement between observed and calculated values up 

 to seven thicknesses of opal for both air and oil con- 

 tact. — J. W. T. Walsh : The theory of decay in radio- 

 active luminous compounds. The theory of destruc- 

 tion of "active centres" put forward by Rutherford 

 to account for the decay of luminosity of radio-active 

 luminous compounds leads to a simple exponential 

 relation in the special case of a compound of constant 

 activity. It has been found for radium zinc sulphide 

 compounds that this relation expresses the observed 

 results to a sufficient accuracy over short periods of 

 less than 200 days, but that it fails to do so over 

 longer periods, such as 500 days, the rate of decay 

 of luminosity becoming gradually slower and slower, 

 so that the brightness tends to a limiting value which 

 is not zero. The paper is an attempt to find a 

 luminosity time relation which will allow of the pre- 

 diction of the ultimate behaviour of compounds of 

 varying composition, and it assumes the operation of 

 some factor acting in a direction opposite to that of 

 the destruction of the active centres. 



Physical Society, June 8. — Prof. C. V. Boys, president, 

 in the chair. — T. Parnell : An alternating-current 

 bridge method of comparing two fixed inductances at 

 commercial frequencies. The paper describes a method 

 of avoiding the troublesome double adjustment re- 

 quired in Maxwell's method of comparing inductances. 

 A current detector, the deflections of which depend on 

 the component of the current in quadrature with the 

 E.M.F., is employed, which makes it possible to 

 arrange that the condition for no deflection depends 

 chiefly on either the inductances or the resistances. In 

 series with the bridge is placed either a non-inductive 

 resistance or a capacity. In the first case the balance 

 depends chiefly on the inductances, and in the second 

 case on the resistances. A few alternate repetitions 

 of the two adjustments suffice to balance the bridge, 

 both for resistances and inductances. As detector a 

 sensitive moving-coil galvanometer in conjunction with 

 a commutator, or a Sumpner electrodynamometer, may 

 be employed ; the latter .proved more satisfactory. — 

 Balth. Van der Pol, jun. : The wave-lengths and radia- 

 tion of loaded antennae. The paper consists of a 

 mathematical treatment of the subject, the following 

 being some of the conclusions arrived at : — ^The radia- 

 tion resistance of a loaded antenna, and also the 

 radiation from the antenna, are dependent not only on 

 the wa%'e-length, but also on the current values at the 

 top and bottom. The radiation cannot, therefore, be 

 written 21 = AT^Z^/A^, where A is constant and T is the 

 R.M.S. current at the base, as is done in most text- 

 books. Riidenberg's formula for flat-top or umbrella 

 antennae is valjd only for very long wave-lengths, with 

 a capacity at the top of the antenna very large com- 

 pared with that of the vertical part, and Austin's table 

 of radiation resistances up to ratios of Z/A = o-4 is based 

 on an unjustifiable extrapolation of Riidenberg's re- 

 sults. The paper also treats of the directions in which 

 the energy is most strongly radiated under different 

 conditions. — Dr. A. GriflBths : A method of preventing 

 sparking at a rapid make-andnbreak, which incident- 

 ally produces colloidal platinum. The apparatus ex- 

 hibited was described in the Philosophical Magazine 

 for March, 189;, p. 2-^2. The device consists of a 

 series of electrolytic cells placed as a shunt across the 

 spark-gap. The electrodes consist of platinum, and the 

 electrolyte of strong- sulphuric acid. The cells polarise, 

 and on making the gap an E.M.F. is introduced 

 opposed to the E.M.F. of the batterv, so that the 



