January i8, 19 12] 



NATURE 



401 



at University College, London, on Tuesday evenings at 

 8.30 p.m., beginning on January 30. The first two 

 lectures will be delivered by Prof. Karl Pearson, and will 

 deal with " Sir Francis Galton : his Life and Parentage, 

 Work and Teaching." 1 ue^e will be followed by two 

 lectures on " Infantile Mortality," by Miss Ethel Elderton 

 and Dr. M. Greenwood, jun. The fifth lecture will be on 

 "Alcoholism," by Dr. David Heron; the sixth on 

 " Physical Degeneracy," by Mr. Bishop Harman ; and the 

 seventh and eighth on " Heredity and Environment " and 

 on " Social Problems," by Prof. Karl Pearson. Further 

 particulars may be obtained on application to the secretary 

 of the college. 



At the annual general meeting of the Royal College of 

 Science Old Students' Association, held on January 13 at 

 the college, Sir William Crookes, O.M., F.R.S., was 

 elected as president of the association on the motion of 

 Captain John Spiller, who shares with Sir William the 

 honour of being the oldest students connected with the 

 college. Prof. R. A. Gregory was elected as one of the 

 vice-presidents in succession to Sir William Crookes, the 

 : remaining five vice-presidents being re-elected. Mr. T. LI. 

 Humberstone and Mr. A. T. Simmons were re-elected 

 secretary and treasurer. The evidence relating to the 

 college presented to the Royal Commission on University 

 Education in London was to have been considered at this 

 meeting, but owing to the. lateness of the hour it was 

 decided to adjourn the meeting, and another general meet- 

 ing will be called shortly, on a date to be fixed by the 

 (ummittee, at which the principal business will be the dis- 

 I ussion of this evidence. The report of the committee 

 showed that the membership of the association had in- 

 creased to 665, of whom 595 are associates of the college. 



The report of the principal of the Huddersfield Technical 

 College, read at the prize distribution on December 21 

 last, has been published in pamphlet form. We find that 

 the age of admission to evening classes was raised by one 

 ! year, and the total of student hours was well maintained, 

 I in spite of the fall in the number of students which followed 

 I the raising of the age of entry. Although a number of 

 individual students engaged in local industries attend day 

 classes for one or more mornings or afternoons in the 

 week, the conditions of employment seem to be unfavour- 

 able to the release of young persons during working hours 

 for the purpose of attending classes. As yet, little success 

 has attended efforts to make systematically organised 

 arrangements for such students. In making recommenda- 

 tions with regard to the award of college diplomas, the 

 staff has not hitherto had the advantage of any outside 

 help or advice, such as is rendered in many university 

 examinations by an external examiner acting conjointly 

 with members of the university staff. To remedy this 

 defect, the governors have sanctioned a scheme for the 

 appointment of honorary assessors, whose cooperation and 

 assistance will, it is expected, prove to be of value in deter- 

 mining these awards. There is an increasingly satisfac- 

 tory relationship of the college with employers of all kinds. 

 Cases are frequent in which students are allowed to leave 

 work early on class nights, or are given help towards the 



Sayment of class fees or the cost of books or instruments, 

 luch interest is displayed from time to time by employers 

 and others in proposals for new classes, as well as in 

 attempts to improve the existing instruction. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, January 11. — Sir Archihaldj Geikie, 

 K.C.H., president, in the chair. — Lord RayieiKh : The 

 propagation of waves through a stratified medium, with 

 special reference to the question of reflection. — Prof. F. T. 

 Trouton : The mechanism of the scmi-permoable mem- 

 brane and a new method of determining osmotic pressure. 

 The amount of water taken up by a liquid, such as ether, 

 from an aqueous solution, the solute of which is insoluble 

 in the liquid, diminishes as the strength of the solution 

 increases, the maximum amount taken up being from pure 

 water. Reasons are given in the paper for expecting that 



I NO. 2203, VOL. 88] 



the amount of water taken up from a given solution would 

 increase under pressure, and further, that at the osmotic 

 pressure of the solution the amount taken up would be 

 the same as that from pure water at the atmospheric 

 pressure. An account is also given of an experimental 

 investigation which has verified these conclusions in the 

 case of a 60 per cent, solution of cane sugar when osmotic 

 pressure is about 80 atmospheres. — Dr. Alois F. Kovarik : 

 Mobility of the positive and negative ions in gases at high 

 pressures. Rutherford and Child have shown that the 

 current t per sq. cm., between two parallel plates when an 

 intense ionisation is confined to the surface of one plate, 

 is given by i = 9V-K/327rd^, where V is potential difference, 

 d distance between plates, and K mobility of ion. When 

 theoretical conditions are fulfilled, the current through the 

 gas in the two directions affords a direct measure of 

 mobility of positive and negative ions. The surface ionisa- 

 tion was obtained by covering one of the plates with an 

 active preparation of ionium, separated by Prof. Boltwood 

 from the uranium residues lent by the Royal Society to 

 Prof. Rutherford. Using high pressures, ionisation is 

 mainly confined within a very short distance of the plate. 

 The theory was tested experimentally, and it was found 

 that over a considerable range « varied as \'^ and inversely 

 as d^. The results for the mobilities of the ions in these 

 gases are as follows : — in dry air and dry hydrogen 

 mobility varies inversely as pressure up to 75 atmospheres, 

 the highest used ; in moist carbon dioxide the product of 

 mobility and pressure is constant up to 40 atmospheres, 

 but for higher pressures the product decreases as the gas 

 approaches the liquid state. The mean values for the pro- 

 ducts of mobility and pressure in atmospheres, for the 

 range of pressures for which the product was constant, 

 are for negative and positive ions, respectively, in dry air 

 i-8g and 1-346, in dry hydrogen 819 and 6-20, and in 

 moist carbon dioxide 067 and 0-705 cm. per sec, for a 

 potential gradient of one volt per cm. — G. A. Shake- 

 spear : A new method of determining the radiation con- 

 stant. The rate of loss of heat of a silvered surface at a 

 temperature of 100° C. in surroundings at 15° C. is 

 observed (a) when the surface is polished, (6) when it is 

 lamp-blacked. The difference is due to difference in radia- 

 tion losses. The ratio of the rates of radiation is obtained 

 by exposing the two hot surfaces in turn to a radiomicro- 

 meter. The rate of radiation from the lamp-black is 

 assumed to be proportional to the difference between the 

 fourth powers of the absolute temperatures 373 and 288. 

 The lamp-black at 100° C. is compared with a full radiator 

 at the same temperature by means of the radiomicrometer. 

 Certain corrections are necessary, and these are dealt with 

 in the paper. As a check on the comparison given by the 

 radiomicrometer, an instrument which constitutes a closer 

 approximation to a full receiver was devised and used. 

 It was found, incidentally, that the apparent radiation 

 from lamp-black depends upon the surface upon which the 

 lamp-black is deposited. The value obtained for <r is 

 5-67 X10-* ergs per sq. cm. per sec. per deg*. — Dr. R. A. 

 Houston : The mechanics of the water molecule. Sup- 

 pose that a hydrogen atom loses one electron to a second 

 hydrogen atom, and that the second hydrogen atom loses 

 two electrons to an oxygen atom. Then the oxygen atom 

 has two negative charges, each hydrogen atom one positive 

 charge, there will be one line of force between the first 

 and second hydrogen atoms and two lines of force between 

 the second hydrogen atom and oxygen atom. Let the three 

 lines of force act as equally strong spiral springs, and let 

 a wave of light pass through a medium composed of such 

 molecules. It is shown in the paper, by moans of the 

 ordinary theory of dispersion, that the absorption spectrum 

 of such a medium consists of two bands, the ratio of the 

 wave-lengths of which is 232. Al.so from the intensity 

 and width of each band it is possible to calculate dm, 

 the ratio of unit charge to the mass of the hydrogen atom. 

 Water is transparent in the ultra-violet and visible spec- 

 trum, and has two great bands in the infra-red at 307 /t 

 and (V15 M. which are not present in oxygen or hydrogen. 

 It is shown in the paper that the values of e/m calculated 

 from these bands are respectively 71 10 and 1550 electro- 

 magnetic units. Hence the structure assumed for the 

 molecule cannot be far off the truth. 



