April 4, 1901 J 



NATURE 



553 



12 per cent, gives an approximately even passage from black 

 into white. 



The discrepancy between the ring-grading and the smooth 

 shading is shown to be probably dui to the contrast effects 

 before mentioned, of which a rough quantitative estimate can be 

 given. 



The curve through 12 per cent, mid-point, with equal incre- 

 ments of sensation correlated with increments of sensation in 

 geometrical progression, is accepted as affording an arbitrary and 

 empirical scale for increase of brightness due to increase in 

 physical luminosity. 



■ Colours are dealt with and even shading is obtained from black 

 into blue, and into red, orange, &c. ; white into similar colours, 

 and one colour into another — for example, red into blue through 

 intervening shades of purple. 



The luminosity of these colours is determined in terms of the 

 arbitrary scale on Sir Wm. Abney's method ; and the results, as 

 deduced from the empirical curve, are compared with those' 

 directly observed by the method of shading in rotating discs. 



For comparison, the results are given in terms of the mid- 

 points of curves analogous to that for the shading of black into 

 white : — 



Midpoint Percentages. 



Deduced from Observed by method 



If these results be accepted as 'giving a sufficiently close 

 agreement, it follows, first, that for colour shading the per- 

 centages of stimulus required are dependent on the lummosity 

 of the colours employed ; and, secondly, that all the data ob- 

 tained by the method of shading can be plotted on a single 

 curve which exhibits the relation of stimulus to sensation in 

 visual impressions. 



If we assume that the black on the arbitrary scale has a value 

 of I 87474, and if this amount be added to the stimuli through- 

 out the scale, so that the white becomes loi "87474, the mid- 

 point 13 87474, and so on, the scale becomes, so far as stimulus 

 is concerned, an absolute scale. And on this absolute scale of 

 stimulus, the sensations, plus some undetermined constant, 

 form an arithmetical series, while the stimuli which are in 

 relation to them form a geometrical series. In other words, the 

 addition of this constant to the summed increments of stimulus 

 at any stage of the scale causes these summed increments to fall 

 into line as the terms of a geometrical progression. The 

 stimulus value of the mid-point on the absolute scale is the 

 geometrical mean between the values of the extremers on the 

 same scale. On this assumption, therefore, and between these 

 limits, Weber's Law and Fechner's expression of it hold good. 



Its validity beyond these limits is questionable. Dr. Waller 

 has shown good reasons for believing that near the threshold of 

 sensation the completed curve shows change of sign, and be- 

 comes sigmoidal. Apart from the evidence he adduces, some 

 such assumption seems to be well nigh necessary if we are to 

 attempt to give a complete curve, which, near the threshold of 

 sensation, does not land us in the maze of difficulties arising 

 from the asymptotic character of a wholly logarithmic curve. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Dr. J. J. SuDBOROUGH, senior lecturer and demonstrator in 

 chemistry of Nottingham University College, has been appointed 

 professor of chemistry at the University College of Wales, 

 Aberystwith. 



Recent gifts in aid of the funds of the McGill University, 

 Montreal, amount to more than 42,000/. Of this sum, nearly 

 one-third was provided by the chairman, Sir Wil'iam C. Mac- 



NO. 1640, VOL. 63] 



donald, who has already given over half a million sterling to the 

 same institution. As the development of the University has 

 recently been mainly on the lines of applied science and medi- 

 cine, it is the faculty of arts which will mainly benefit by this 

 new donation. 



In the Court of Appeal, on Monday, it was decided that 

 School Boards cannot provide out of the rates for instruction in 

 subjects prescribed by the Department of Science and Art, either 

 in day schools or in evening continuation schools. It is thus 

 declared illegal for a School Board to expend money out of a 

 local rate for any purpose other than elementary education. In 

 schools in which instruction is given in subjects such as those in 

 the Science and Art Directory any assistance afforded to them 

 must come from funds other than those provided by the rate- 

 payers for primary education. As many School Boards have 

 been providing instruction of this kind, it is evident that the 

 decision accentuates the urgent need of an authority to describe 

 the powers of the various bodies concerned with primary and 

 secondary education. 



The Association of American Universities recently met at 

 Chicago and discussed, among other topics, (i) inter-university 

 migration of graduate students ; (2) fellowship ; and, (3) the 

 examination for the degree of doctor of philosophy. From a 

 report in Science we learn that with regard to the first topic it was 

 considered desirable to promote by all possible means the inter- 

 umversity migration of graduate students, to the end that they^ 

 may come under the guidance of teachersof varying points of view^ 

 and so may receive the broadest possible introduction to theijr 

 chosen field of study. As regards the question of fellowships, the 

 opinion was expressed that it would be advisable to make some of 

 the fellowships distinctly research fellowships, to be awarded, 

 only to students who had already taken the degree of doctor of 

 philosophy, and who had, therefore, received their academic 

 equipment for their life work. In discussing the best type of 

 examination for the doctor's degree, it was held very emphatic- 

 ally that the practice which is growing up in American universi- 

 ties, especially in some of the departments dealing with natural, 

 science subjects, of permitting the candidate to pass his exam-~ 

 ination course by course, as is usual in undergraduate instruction, 

 is a pernicious one, and one which stands in the way of the 

 attainment of the best and broadest scholarship. It was held 

 that the examination for the doctor's degree should, in all cases, 

 be upon subjects and not upon courses of instruction, the under- 

 lying principle being that the courses of instruction which a 

 graduate student attends are but a small part of the work which , 

 he is supposed to do in order to prepare himself for his 

 examination. 



Mr. Andrew Carnegie has presented to the Iron and Steel 

 Institute thirty-two looo-dollar Pittsburg, Bessemer and Lake 

 Erie Railroad Company 5 percent, debenture bonds, the income 

 derived from which will be applied to awarding annually one or 

 more research scholarships of such value as may appear expedient 

 to the council of the Institute. The awards will be made on the 

 recommendation of the council irrespectively of sex or nationality. 

 Candidates, however, must be under thirty-five years of age, and 

 application must be made on a special form to the secretary of' 

 the Institute before the end of April in every year. The scholar- 

 ships will be tenable for one year, but the council will be at 

 liberty to renew them for a further period if thought desirable 

 instead of proceeding to new elections. The object of this 

 scheme of scholarships is to enable students who have passed 

 through a college curriculum, or have been trained in industrial 

 establishments, to conduct researches in the metallurgy of iron 

 and steel and allied subjects, with the view of aiding its advance 

 or its application to industry. It is suggested that the National 

 Physical Laboratory — on the governing body of which the Iron 

 and Steel Institute is represented — would for many reasons be a 

 very suitable establishment in which such researches could be 

 carried out. There is, however, no restriction as to the place of 

 research that may be selected, whether University, technical 

 school, or works, the only absolute condition being that it shall 

 be properly equipped for the prosecution of metallurgical inves- 

 tigations. The results of the researches are to be communicated 

 to the Iron and Steel Institute in the form of a paper to be sub- 

 mitted to the annual general meeting of members. If the paper 

 appears to the council to be sufficiently meritorious, the author 

 will be awarded the Andrew Carnegie gold medal. 



