September 3, 1908] 



NA TURE 



439 



it is still more difficult to fix a variety ; this is abundantly 

 proved by the difficulty of improving wheat. A single ear 

 is selected because it possesses some desirable property ; 

 the seed from it is sown ; an ear is selected showing the 

 same property, and the process is continued for several 

 generations. " Pedigree " seed is thus obtained, but it 

 rarely remains true ; the farmer has to renew his stock 

 periodically from the raiser, who keeps on the selection 

 process. The work done on the selection of seed wheats 

 at the Roseworthy Agricultural College is described in the 

 Journal of Agriculture for South Australia ; it is hoped in 

 this way to obtain strains which will keep their character 

 for two or three seasons, and prove much more profitable 

 than the seed wheat now in use. There is no question 

 that a good deal can be done by selection, especially in 

 South .'\ustralia, where, we are told, little or no attention 

 has been given to the matter, and the best grain is some- 

 times sold and the worst kept for seed. But it is now 

 clear that the only safe method for the improvement of 

 crops grown from seed is to breed on Mendelian lines, as 

 Biffen is doing at Cambridge, and South Australia would 

 do well to breed, as well as to select, seed wheat. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Cambridge. — Mr. Robert Forsyth Scott, fellow and 

 senior bursar, has been elected master of St. John's 

 College in place of the late Rev. Dr. Charles Taylor. 



Prof. D. J. H-amilton, F.R.S., has, in consequence of 

 ill-health, resigned the chair of pathology in the University 

 of .'\berdeen to which he was appointed in 1882. 



.Mr. VV. Galloway Duncan, of Dundee, has been 

 appointed head of the Government Engineering School, 

 Dacca, Bengal. 



The Senate of the University of Bombay has, according 

 to the Allahabad Pioneer Mail, decided to include a test 

 in science for all candidates for a degree. 



The jubilee of the University Museum at Oxford will be 

 celebrated on October 8. Honorary degrees will be con- 

 ferred upon Prof. Arrhenius and Dr. Vernon Harcourt, 

 F.R.S., and a bust will be unveiled of Prof. W. F. R. 

 W'eldon, who died in .^pril, 1906. 



The Year-book of the Michigan College of Mines, 

 1907-8, shows that the college is better equipped and more 

 prosperous than at any previous period since its founda- 

 tion in 1885. There are now 253 students, their average 

 age being 22J years. The concentration of effort on train- 

 ing men for the field of mining, the situation of the college 

 in the heart of the copper-mining region of Lake Superior, 

 together with its special methods of instruction, have 

 brought to the institution a large measure of success. 

 Considerable range is allowed in selecting the courses or 

 subjects which shall compose a particular student's curri- 

 culum, and the Record of Graduates, published as a 

 separate pamphlet, giving their occupations, affords 

 interesting evidence of the success attained. 



It is now recognised that the teaching of hygiene and 

 physical exercises to pupils in both primary and secondary 

 schools is of equal importance to their education in other 

 branches of knowledge. In primary schools it is of special 

 importance, as the opportunity for games is often absent 

 in large towns. For this reason the Board of Education 

 makes a knowledge of the methods of teaching and the 

 aims of physical education one of the necessary parts of 

 the equipment of a primary-school teacher. With this 

 qualification is associated the requirement of a knowledge 

 of hygiene, particularly in relation to schools and school 

 children. For the last ten years a systematic course for 

 women has been carried on at the South-Western Poly- 

 technic, Chelsea. This training has been so successful 

 that the course, originally designed for two j-ears, has 

 developed now into one of three years. The governors of 

 the Chelsea Polytechnic are now instituting a similar 



XO. 2027, VOL. 78] 



course for men, and for this purpose they have engaged 

 a teacher of gymnastics on Ling's Swedish system. In the 

 first instance a course of one year for men will be provided, 

 and it is hoped to obtain students who have passed already 

 two years in training colleges, as well as university 

 graduates with an initial equipment of general and 

 elementary scientific knowledge. Such students, after a 

 year devoted mainly to the study of hygiene, physiology, 

 gymnastic exercises, and the part of anatomy bearing on 

 physical training with study of the theory of movements, 

 should be in a position to take charge of physical educa- 

 tion in schools and to take their proper positions as teachers 

 of usual subjects. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, Match 5. — "On the Nature of the 

 Streamers in the Electric Spark." By Dr. S. R. Milner. 

 Communicated by Prof. W. M. Hicks, F.R.S. 



(i) The streamers in the inductive spark consist of 

 metallic vapour, the atoms of which are charged, and the 

 motion of the vapour towards the centre of the spark gap 

 is mainly due to the action of the electric force of the 

 spark on the charged atoms. The chief evidence in support 

 of this consists in a number of photographs in which the 

 streamers move back again towards the poles as the 

 oscillating electric field of the spark reverses its direction. 



(2) Very great differences were found in the appearances 

 of the streamers which correspond to the different lines of 

 the same metal. The streamers may be divided in this 

 respect into three classes, between which there is in most 

 sparks a sharp distinction. 



(a) Blurred streamers, which are often partly masked by 

 the whole spark gap being filled with their light. These 

 invariably correspond to lines prominent in the arc. 

 (b) Sharply defined streamers, which appear throughout 

 the whole time during which the electrical discharge lasts. 

 These correspond to pure spark lines, i.e. lines which are 

 not present in the arc under ordinary conditions, (c) A 

 third class of streamers show very brightly at the first 

 oscillation, but fade away so rapidly that they appear for 

 only one or two oscillations, even when the other lines, 

 initially no brighter, show ten or twelve. These lines are 

 very sensitive to the influence of self-induction in the 

 circuit ; they are very bright in the condensed spark with- 

 out inductance, but disappear from the spectrum altogether 

 when a moderate inductance is inserted. 



By studying the duration of the lines in the inductionless 

 spark, the difference between the three classes of streamers 

 is found to be solelv a auestion of the duration of the 

 luminosities of the metallic lines to which they correspond, 

 the arc lines having a long, the spark lines a short, and 

 the " condensed spark " lines a very short, duration. 



(3) No other difference than this one of the dufations of 

 the lines has been discovered in the character of the 

 streamers. The photographs obtained show clearly that 

 the velocities of the streamers corresponding to the different 

 lines in the same spark are the same, in spite of the 

 different character of the streamers. 



.^pril 30. — " The Supersaturation and Nuclear Condensa- 

 tion of certain Organic Vapours." By T. H. Laby. 

 Communicated by Prof. J. J. Thomson, F.R.S. 



(i) The least expansion, which causes condensation in 

 air initially saturated with an organic vapour and ionised 

 by Rontgen rays, has been determined for five esters, six 

 acids (formic to iso-valeric), and iso-amyl alcohol. 



(2) In the case of acetic acid the expansion required was 

 greater for feeble Rontgen rays than for more intense 

 ones. 



(3) The supersaturation, S, existing at the end of each 

 of the expansions mentioned in (i) has been calculated, 

 and also for four alcohols and chloroform from Przibram's 

 experiments. 



(4) The acids are found to have the largest values of S 

 and the alcohols the least. The isomers examined have 

 the same value for S with one exception. In the case of 

 the alcohols, ethyl to iso-amyl, a fairly regular decrease 

 in S accompanies the addition of a CH, group. 



