46 



NA TURE 



[May 9, 1907 



remarkable, the omissions are not less so. The explan- 

 ation that Dr. Forstemann offers for the absence of refer- 

 ence to Jupiter or Saturn in these hieroglyphs is that their 

 synodic periods are too nearly equal to the solar year. 

 This can scarcely be regarded as a satisfactory explan- 

 ation. But still more curious is the small attention paid 

 to the moon. It is true that the writer traces a rcf<'rence 

 to the synodic period of 29I days, but the effort strikes 

 one as rather forced, and the reference is by no means 

 so prominent as in the case of Venus. There is, too, no 

 mention of eclipses. In one passage Dr. Forstemann finds 

 an allusion to clouds, and one need be very cautious how 

 he disagrees with the opinion of so distinguished an 

 expert. But it seems scarcely likely that such ordinary 

 phenomena as clouds should be referred to, in what is 

 evidently the production of considerable labour, intended 

 for a permanent record. This omission is the more strange 

 if we accept Dr. Seier's view that the Maya documents 

 declare an advance on the Mexican pictorial writings, and 

 possess greater accuracy, indicating more elaborate com- 

 putation. For in a Mexican MS., Codex Vaticanus, No. 

 3773, ^ve have a distinct reference to the sun being 

 devoured by a jaguar, and causing or explaining a solar 

 eclipse (Kingsborough, iv., 22). 



The commentary offers many other instances in which 

 ingenuity and resource are exhibited in deciphering or in 

 assigning meanings to these pictures, but here we can ao 

 no more than express our admiration of the patience and 

 skill, which have solved so many enigmas and offered so 

 many interesting suggestions. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Oxi-ORD. — The Robert Boyle lecture for 1007 will be 

 delivered by Prof. Karl Pearson, on " The Scope and 

 Importance to the State of National Eugenics," on Friday, 

 May 17, at g p.m., in Balliol Hall. 



The Herbert .Spencer lecture for 1907 will be given by 

 Mr. Francis Gallon, on " Probability, the Foundation of 

 Eugenics," in the Sheldonian Theatre on Wednesday, 

 June 5, at 2.30 p.m. 



Mr. C. Ci. Douglas, formerly Demy of Magdalen College, 

 has been elected to an official fellowship in natural science 

 at St. John's College. 



Cambridge. — During their visits to England, it is pro- 

 posed to confer the degrees of Doctor of Law upon the 

 King of Siam and Prince Fushimi. 



At a congregation to be held in June, the degree of 

 Doctor of .Science, honoris causa, will be conferred upon 

 Sir Clements R. Markham, Colonel Sir T. H. Holdich, 

 and Sir T. R. Fraser, professor of materia medica and of 

 clinical medicine in the University of Edinburgh. 



Prof. Hughes has been nominated to represent the 

 University at the celebration of the centenary of the Geo- 

 logical Society of London in September. 



Mr. A. D. Imms, Christ's College, has been appointed 

 professor of biology at Allahabad University. 



Prof. Nuttall will deliver his inaugural lecture in the 

 anatomical lecture theatre on Wednesday, May 22, at 

 4.30 p.m. 



\n exhibition of 50!. a year tenable for two years is 

 offered by the governing body of Emmanuel College to an 

 advanced student commencing residence at the college in 

 October. .>\pplication should be sent to the Master of 

 Emmanuel not later than October i. 



The professorship of agriculture is vacant by the 

 resignation of Prof. Middleton. The title of the pro- 

 fessorship will in future be '" The Drapers Professorship 

 of .■\griculture. " The election of a professor will take 

 place on .Saturday, June i, at the University Offices, St. 

 .'Andrew's Street. Candidates for the chair are requested 

 to communicate with the Vice-Chancellor of the University 

 on or before Thursday, May 23. 



The Mercers' Company lectures on " The Internal Media 

 of the Body imd their Relation to the Tissues " will be 

 given in the physiological department of LTniversity College 

 (University of London) by Prof. E. H. Starlingj F.R.S., 



NO. 1958, VOL. 76] 



on Fridays at 5 p.m., commencing Friday, May 10. 

 These lectures are open to all students of the London 

 medical schools, and to medical men on presentation of 

 their cards. 



In the course of some remarks at the annual dinner of 

 the Institution of Mining and Metallurgy on May 3, Mr. 

 R. McKeniia, M.P., President of the Board of Education, 

 I referred to the new Imperial College of Science and 

 Technology, and said ho hopes that a year hence it will 

 be in a state of flourishing existence. He announced that 

 this week it will be his duty to petition the King for a 

 charter for the new college. The Bessemer memorial 

 fund now amounts to 13,000/. or 14,000/., and it is hoped 

 that the amount will rapidly be increased to 30,000/. or 

 40,000/. The very best equipment the world can produce 

 is needed for the Roy.il School of Mines, which even 

 without such facilities iias created a world-wide reputation 

 for itself. 



In the House of Commons on Monday, Mr. Murray 

 Macdonald asked the Prime Minister whether, in view of 

 the recent and prospective increased expenditure upon the 

 iinprovement and development of State-aided education, of 

 the importance of connecting it more closely with the 

 universities, and of the fact that more than twenty-six 

 years had elapsed since the last public inquiry into the 

 universities and colleges of Oxford and Cambridge was 

 held, he would appoint a commission to examine into the 

 desirability of amending the existing enactments with re- 

 gard to the finances, emoluments, and government of these 

 universities. In reply to the question. Sir H. Campbell- 

 Bannerman said : — I am disposed to agree with my hon. 

 friend that the conditions of the universities are ripe for 

 a thorough and comprehensive inquiry, but I am not 

 disposed to add, at the present moment, to the number of 

 Royal Commissions already existing. 



SOCIETIES AND ACADEMIES. 

 London. 

 Royal Society, Februarv 28. — " On the Dispersion in Arti- 

 ficial Double Refraction." By Dr. L. N. G. Filon. 



Communicated by Prof. F. T. Trouton, F.R.S. 



It is well known that glass compressed unequally in 

 different directions behaves like a temporary crystal. If 

 T|, T, be the principal stresses in the wave-front, t the 

 thickness of glass traversed, then the relative retardation 

 of the two oppositely polarised rays is R = C(T,— TjK. 

 C may be called the " stress-optical coefficient " of the 

 glass. 



The experiments described were undertaken in order to 

 find out how C for borosilicate glasses varied with the 

 colour of the light used and with the composition of the 

 glass. 



Polarised light was passed through a combination of 

 glasses under flexure optically equivalent to a slab under 

 uniform stress. It was then analysed by a Nicol and 

 spectroscope. The spectrum was crossed by a dark band 

 whenever R = integer multiple of \. The measurement of 

 A. then gave R and C. 



It is found that, on the whole, the dependence of the 

 stress-optical coefficient on the colour is very well ex- 

 pressed by the empirical formula 



il-'lt')- 



C„, X„ being constants. This gives a hyperbolic law. 



In certain glasses, however, systematic deviations from 

 this law exist. These deviations are local in character, 

 and their study suggests a strong analogy with the effect 

 of absorption bands on the dispersion in single refraction. 



With regard to the effect of chemical composition, it 

 appears that an increase in the percentage of B,Oj in- 

 creases C„ ; an increased percentage of K,0 probably de- 

 creases C„. A„, on the other hand, seems roughly inde- 

 pendent of the composition, so that, for the glasses ex- 

 amined, the curves of C plotted to A. differ only in their 

 scale ; the dispersion increases with the stress-optic^i 

 coefficient. 



