ii8 



NATURE 



[March 24, 1910 



The State is making a change in many of the endowed 

 charities which are scattered all over the country. In the 

 course of time it will be possible, not only to apply the 

 whole of the educational endowments to the original pur- 

 poses of their founders, but to combine the small endow- 

 ments so as to make them effective. 



The issue of the Journal of the .Association of Teachers 

 in Technical Institutions for January contains a paper by 

 Mr. John Wilson, the president of the association, on the 

 relation of the technical institution to the modern university. 

 After commenting upon the advanced character of much of 

 the teaching carried oh in technical institutions, and men- 

 tioning the creditable amount of research work published 

 yearly by the staffs and senior students of these schools 

 and colleges, Mr. Wilson gave some interesting statistics 

 as to the students who graduated in science at the Uni- 

 versity of London during 1909. It appears that altogether 

 292 candidates were awarded the degree of B.Sc, and that 

 57 of these studied entirely at technical institutions, while 

 if the students who did part of their work at a technical 

 institution are included, the number reaches 80. Mr. 

 Wilson also gives the numbers of registered " internal " 

 students and " recognised " teachers in London poly- 

 technics, and compares the total with those in the case 

 of certain other London colleges. During the session 

 1908-9, the number of registered internal students in the 

 faculty of science was : — at University College, 224 ; 

 King's College, lys; ; East London College, 162 ; and at 

 eight " recognised " polytechnics, 372. In these eight poly- 

 technics there are 94 " recognised " teachers of arts, 

 science, and engineering. In other words, the polytechnics 

 have become important centres of university work.. Mr. 

 Wilson maintains that the success of even the limited 

 recognition of London polytechnics by the University of 

 London clearly points to the desirability of the extension 

 of that recognition by the University and to a widely 

 increased measure of recognition of local technical institu- 

 tions by the provincial universities. 



At a meeting of the Royal Dublin Society on March 9 

 Prof. Senier delivered a lecture on " The University and 

 Technical Training." From the account of the meeting in 

 the Irish Times of March 10 we learn that Prof. Senier 

 considered four types of institutions for the advancement 

 and diffusion of learning and of its applications to society ; 

 institutions of acknowledged university rank or residential 

 college universities, exemplified by Oxford ; the research 

 university, as seen at Berlin ; the examination university, 

 first known in Napoleon's University of Paris; and the 

 technical research university, Charlottenburg. In England, 

 he said, where numerous new universities have been estab- 

 lished in recent years, the type adopted has been a com- 

 bination of the German Research University and the 

 German Technical Research University, the one or the 

 other type predominating, according to local needs, and 

 the whole adapted to its surroundings, particularly to the 

 conditions of secondary education. Whatever view may be 

 held respecting the German practice of separating these 

 two types, as adapted to German conditions. Prof. Senier 

 thinks that for the conditions which prevail in the British 

 Isles the combination of the two in new universities is a 

 wise arrangement. The two new universities in Ireland 

 are also of this combined type, and are to be adapted to 

 Irish educational conditions and the needs of the country. 

 After directing attention to the influence Liebig exerted 

 through his students in the direction of scientific research, 

 Prof. Senier said so great is that influence that science 

 laboratories after the model of Giessen have become the 

 recognised attribute of science professorships throughout 

 the world. Another advantage possessed by the German 

 university is the character of the leaving examination of 

 the secondary school. It corresponds to a matriculation 

 examination, with the added knowledge acquired by about 

 two years' universit}' study in arts, and its acceptance by 

 the university as evidence of sufficient knowledge for 

 matriculation relieves the university of the practice of 

 giving the student an examination as his first experience 

 on entering. In Prof. Senier's opinion secondary schools 

 should abandon all attempts to teach experimental science. 

 To rival the work of the German universities the better 

 organisation and coordination of the entire educational 

 NO. 2108, VOL. 83] 



system is necessary. Germany has built up a chemical 

 industry with tens of millions of pounds annually through 

 the agency of research chemists, methodically trained in 

 technical schools. German manufacturers know the value 

 in dividends of the services of trained research chemists ; 

 Irish and English manufacturers do not. 



SOCIETIES AND ACADEMIES. 



London. 

 Physical Society, February 25.— Prnf. H. L. Callendar, 

 F.R.O., president, in the chair. — Prof. J. Perry : Tele- 

 phone circuits. The author published a paper in the 

 Proceedings of the society in 1893 showing how voltage 

 V and current c are attenuated along a telephone or sub- 

 marine telegraph line, a line with resistance r, capacity k, 

 inductance /, and leakance 5 per unit length ; currents are 

 of the form sin qt. When Iq/r is considerable the mathe- 

 matical expressions become simple. It was pointed out that 

 the introduction of I is of great benefit. The author now 

 points out that k may be made negative by the use of 

 inductance leaks to earth, and I may be made negative 

 by the use of condensers in series with the line. To 

 introduce I, as Mr. Pupin has done, by inductance coils 

 at equidistant places on the line, or to introduce the other 

 properties mentioned by placing other contrivances at equal 

 distances, is a mathematical problem of great complexity. 

 Contrivances placed close together have the same effect as 

 the continuous distribution of properties, but there is con- 

 siderable expense ; the problem is to find how far apart 

 the contrivances may be placed so that the effect produced 

 shall still be beneficial. Mr. Pupin has given a rule for 

 the spacing of his coils, but practical men dispute its 

 accuracy ; nobody has given a rule for other contrivances ; 

 the object of the author is to give an easy method of 

 calculation which is practically correct, and can be used 

 when the contrivance is any network or other combina- 

 tion of resistances, inductances, and capacities — some being 

 leaks to earth — and it may include transformers, motors, 

 and generators. Suppose there are contrivances at the 

 equidistant places A, B, &c., m miles apart in a cable 

 which has the above-mentioned properties r, k, I, and 5. 

 There is a contrivance the terminals of which are A and 

 A„, another the terminals of which are B and B„ ; between 

 A„ and B there is m miles of cable. Let the currents in 

 the line at A, A^, and B be c, c„, and C. Let the voltages 

 at these points be v, v„, and V. The assumption on which 

 the whole method is based is that V/C = v/c = p. This is 

 practically true everywhere in a long line except near the ji 

 ends. Now whatever be the nature of the contrivance, we | 

 can calculate v^ and c„ from v and c. It is also known 

 that 



TT 1 . r-\-loi • , 



y = v^ co'h w«+ („ snn vm. 



Q = Cc, cosh inn + ■ 



when 



r + l(]i 

 n = V (;■ + Iqi) (j + kqi). 



z'n sinh w//, 



Putting V/C or p equal to t'/c, we have a quadratic to 

 calculate p, and therefore V and C, and the problem is 

 solved. Taking c = singf and calling it i, then t) = p. 

 Whatever the contrivance may be, we find that V = o + j8p 

 and C = a4-bp, where o, /3, a, and h are given in value; 

 they are usually unreal quantities of the form M + Nt, 

 where t is >J — \. Solving for p, and finding C, we have 

 two answers which are reciprocals of one another. If 

 |(a + /3) be called P, and this is very easily evaluated, 

 then 



c=p±-v/p*^r 



Examples of the use of the method are given, some show- 

 ing that the detached contrivances produce much the same 

 and others very different effects from what might have 

 been expected from a study of the cable with continuous 

 properties. It was shown that a line may have contri- 

 vances somewhat far apart which will tune it to a musical 

 note merely, so that it acts almost like an ohmic resist- 

 ance, but which will not transmit well the currents of 

 other frequencies, and that for the commercial transmission 



