'622 



NA TURE 



[April 28, 1898 



the scale at a metre's distance was obtainable with a current of 

 o "000,000,0005 of ^" ampere. At present, under such cir- 

 cumstances, a similar deflection would be obtained with 

 0000, 000,000, 0012 ampere, that is to say, the apparatus is 

 about 400 times as sensitive as it was when first described. 



At present the bolometric apparatus, under the conditions 

 already cited, will indicate a change of temperature in its strips 

 of, at any rate, much less than one-ten-millionth of one degree 

 Centigrade. S. P. Langley. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Mrs. Phebe Hearst has offered to erect for the University 

 of California a new building for the School of Mines. 



Draughtsmen and engineering students familiar with the 

 principles of the science of steam, are given opportunity of 

 advancing their knowledge by a special class in steam-engine 

 trials which will commence at the South-Western Polytechnic, 

 Chelsea, on May 17, and terminate on June 28. The class will 

 be conducted by Mr. W. W. F. Pullen and Mr. H. A. Clark. 



The trustees of Cornell University have just established a 

 Medical Department and a State College of Forestry. The 

 medical department will be situated in New York City, and its 

 faculty will be made up principally of those surgeons and 

 physicians who have heretofore been connected with the medical 

 department of New York University ; including all but three of 

 the instructors of that department. The endowment of the new 

 medical school is by a donor whose name is not disclosed. The 

 College of Forestry established by Cornell University will be 

 situated* at Ithaca, and called the State College of Forestry, 

 having been authorised and endowed by the State with a grant 

 of 10,000 dollars by the legislature which adjourned a few days 

 ago. Prof. Bernard E. P'ernow, director of the United States 

 Division of Forestry, has been made director of this department. 



One of the most important educational problems at the 

 present time refers to the coordination of the work of the 

 University and Technical Colleges with that of other educational 

 institutions in the neighbourhood. It is unfortunate that in several 

 cities the educational institutions are competing with one 

 another instead of working together as an organic whole, in 

 which each part has a definite function to perform. Efforts are, 

 however, being made in the large provincial centres to prevent 

 the undesirable overlapping which at present exists, in order to 

 make the various educational institutions complement each 

 other's work without competition. Summaries of what has been 

 done in this regard at Birmingham, Manchester, Plymouth, and 

 Sheffield appear in the current number of the Record of Technical 

 atid Secondary Education. In Birmingham, though no formal 

 machinery exists for the coordination of educational work, the 

 various institutions have adapted their organisation to the cir- 

 cumstances of their environment, supplying any need that was 

 felt, and avoiding duplication of function. An educational 

 ladder has, in fact, been constructed, up which a boy may climb 

 from the Board School to the highest University honours without 

 exciting the jealousy of other schools than those which he 

 attended. This event actually occurred last year, when Mr. W. H. 

 Austin, who began his education at a Birmingham Board School, 

 came out Senior Wrangler at Cambridge. In Manchester the 

 provisions for coordination take the form of an agreement 

 between the Technical Instruction Committee of the City 

 Council and the School Board, and between the authorities of 

 Owens College and the Manchester and Salford Technical 

 Schools. As between Owens College and the Technical Schools 

 it is arranged that the latter shall aim at demonstrating how the 

 general principles of science and art may be applied to the 

 advancement of trade and industry, whilst the college will 

 eschew these obviously bread-and-butter subjects, and address 

 itself to the higher walks of pure science. In Plymouth, also, a 

 scheme has been arranged which correlates and connects the 

 whole of the science and art teaching of the town, from the 

 infant school upwards. In Sheffield a scheme which secures the 

 effective coordination and economical management of the Board 

 Schools, the Technical School, and the School of Art, has been 

 at work since last September, and appears to give entire satis- 

 faction to all concerned ; and Bradford has just taken steps to 

 grade its various educational forces. Through all the schemes 

 one main principle runs — that, namely, of making the common 

 schools, Primary and Secondary, the kindergarten and nursery 

 of science and art, and of making the Technical Schools true to 



their name as the places where is taught the application of science 

 and art to the purposes of industry and commerce, while to the 

 University Colleges are allocated the higher scientific studies. 

 These examples should encourage other courtty boroughs to con- 

 sider and adopt educational schemes which will prevent waste 

 of effort and do away with conflicting interests. 



SOCIETIES AND ACADEMIES. 

 London. 

 Physical Society, April 22.— Mr. Shelford Bidwell, F.R.S., 

 President, in the chair. — A paper by Prof. T. C. Porter, on a 

 method of viewing Newton s rings, was read by Prof. S. P. 

 Thompson. If a parallel beam of light from a rectangular slit 

 falls at oblique incidence upon a plane plate of glass, the first two 

 reflections occur at the upper and lower surfaces of the glass, 

 respectively, and give two corresponding images that may be 

 formed on a screen. If now a second glass plate is added below 

 the first, and parallel to it, at a short distance, four images of 

 the slit appear on the screen. But when the lower plate is 

 brought into contact with the upper one, the reflection from the 

 lower surface of the upper plate follows the same path as that 

 from the upper surface of the lower plate, so that only three 

 images are now to be distinguished. For the two glass plates 

 the author substitutes a " Newton's rings" apparatus, and by 

 the above device for eliminating a set of reflections he is able to 

 restrict the illumination to the light that comes from the two- 

 interior surfaces. As thus observed, the colours of the rings 

 are very brilliant. When the plates are very clean, the darkest 

 area of the " black" spot has a sharply-defined edge, similar to 

 that of the black film of a soap-bubble. By using mono- 

 chromatic light, the various sets of rings may be photographed ; 

 they appear as several systems of concentric circles, the systems 

 intersecting one another. This method of illumination by a slit, 

 enables Newton's rings to be viewed free from all light except 

 that due to reflections at the bounding surfaces of the air-space 

 between the plates. It reveals to the eye the subordinate in- 

 terference-systems that coexist with the primary rings, and 

 it demonstrates which of these reflections must be taken into 

 account in the theory of the phenomenon. Moreover, it sup- 

 plies a means for analysing these systems, and it indicates that 

 the interference of monochromatic light is never complete under 

 these circumstances. Prof. Herschel said it was rather difficult 

 to follow the arguments of the author without witnessing the 

 phenomena. Much complication was introduced by the suc- 

 cessive reflections ; it was not clear what became of them. There 

 was no doubt as to the advantage of a narrow slit for the illum- 

 ination. He thought some of the secondary reflections might be 

 got rid of by using plates that were slightly prismatic. Prof. 

 Thompson had, in his own laboratory, verified the advantages o» 

 the author's method of illumination. The result was a very 

 sharply-defined first system of rings. Curves of subordinate 

 interference were easily to be observed by this arrangement. 

 Prof. Boys noticed in the photograph of the ring-systems that 

 the independent systems of bands were distorted at the points of 

 intersection. The intersecting curves formed a sort of honey- 

 comb, or hexagonal system, instead of a system of curvilinear 

 quadrilaterals. This distortion reminded him of similar effects 

 observed in the photographs of " ripples." Mr. Edser said he 

 had often noticed similar distortions, but he had always been able 

 satisfactorily to explain them as being the result of imperfect 

 focussing. The author had referred to the fact that a thin film 

 when viewed by reflected light appears black. A phase-change 

 of half a wave-length takes place either on reflection at a rarer, 

 or at a denser medium ; but there is no information from which 

 to decide between these two alternatives. The truth of the 

 assumption that the phase-change occurs at the denser medium 

 seems to depend, so far as experimental evidence is concerned, 

 upon the observation that in Lloyd's bands the central one is 

 black. To produce the Lloyd's bands only one mirror is used ; 

 the bands produced by Fresnel required three mirrors. Wernicke 

 performed an interesting series of experiments in which white- 

 light reflected for various angles of incidence from a thin sheet 

 of glass was examined spectroscopically. The spectrum was 

 crossed by numerous black bands, and from the position of 

 these bands in the spectrum the thickness of the glass was cal- 

 culated. The calculated thickness when the angle of incidence 

 was great, differed from that obtained with small angles of 

 incidence ; the conclusion was that when light is internally 

 reflected, even at an angle of incidence less than the angle of 



NO. 1487, VOL. 57] 



