December 8, 1904] 



NA TURE 



141 



the United States of America, where, by their munificent 

 donations, counting by millions, they have covered the land 

 with a net-work of universities which have brought higher 

 education within the reach of almost every citizen. I hope 

 the time is coming when men who have more than they 

 want, more, perhaps, than is good for them, can find no 

 better opportunity of disposing of the surplus than by bene- 

 factions which not only are of present usefulness, but, what 

 is of more importance, are of permanent advantage to the 

 community amongst which they live." 



O.N Thursday last, December i, the prizes and certificates 

 gained by students of the Sir John Cass Technical Institute 

 during the session 1903-4 were distributed by Sir William 

 White, K.C.B., F.R.S., when the chair was' taken by Sir 

 Owen Roberts, chairman of the governing body. Sir 

 William White, in the course of his address, said that 

 during his recent visit to America he had had the oppor- 

 tunity of studying the methods of technical education in 

 vogue there, and he must certainly confess that both 

 America and Canada can teach us a great deal so far as 

 technical colleges in general, and the interest taken by 

 employers of labour in the future employment of men trained 

 in technical institutions, is concerned. The essential 

 advantage which .-Vnierica and Canada, and also Germany, 

 possess over this country is that they are all imbued with 

 the idea that it is a wise investment on the part of a nation 

 to provide for all kinds of education from the elementary 

 up to the highest. It is almost impossible to make expendi- 

 ture on education too lavish, provided it is well directed, 

 if the nation is to be well educated. This country, in his 

 opinion, will never reach a truly healthy condition until 

 everv man or woman, in whatever position the accident of 

 birth may place them, shall, if they possess the capabilities, 

 have also the opportunities of self-culture. Nevertheless, 

 there is one respect, he thought, in which this country 

 stands supreme. It is in the provision of evening classes for 

 the. working man and the working woman who, from the 

 very nature of their circumstances, are compelled to work 

 all day to get a living. Employers should assist these 

 educational classes more than they do at present. The 

 London and South-Western Railway Company are doing 

 what may well be done by other large employers. They 

 grant to the apprentices in their works at Nine Elms the 

 necessary time to attend the early morning classes at the 

 Battersea Polytechnic. The apprentices are allowed to go 

 to these classes twice a week, and are paid for the time 

 that they are away from the company's service, on the 

 condition that they do a certain amount of study at home, 

 thus completing in the evening the training which they 

 receive during the day at the polytechnic. This is not 

 altogether an experiment. The Admiralty has done the 

 same thing for fifty years or more, with the result that 

 the .Admiralty, from the apprentices in its own dockyards, 

 has trained not only many of its principal shipbuilding 

 officers and naval architects for the Royal dockyards and 

 the Admiralty service, but has also furnished to the private 

 shipbuilding industry of the country some of its most 

 famous shipbuilders. The leaders and managers in those 

 great private establishments to-day are in no small pro- 

 portion drawn from men who were trained in the .Admiralty 

 service under the system which has been in operation, and 

 by which every apprentice who cares to improve his mind 

 has the opportunity to do so. If employers will give the 

 utmost encouragement to institutions like the Sir John 

 Cass Institute, they will be rewarded by having capable 

 men on their staff who will know the principles of their 

 business. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, November 17. — " The Electrical Con- 

 ductivitv and other Properties of Sodium Hydroxide in 

 .'\queous Solution, as Elucidating the Mechanism of Con- 

 duction." By W. R. Bousfleld, K.C., M.F., and T. M. 

 Lowryi D.Sc. 



The original object of the research was to investigate 

 the decay, as the temperature rises, in the " ionising " 

 properties of water, which is manifest in the inflected 



character of the curves e.xpressing the relation between 

 temperature and conductivity in aqueous solutions of the 

 alkalies.' The principal results of the investigation are as 

 follows : — 



(i) In the most dilute solutions, in which " ionisation " 

 is nearly complete, and again in the most concentrated 

 solutions, the curves expressing the relation between 

 molecular conductivity and temperature in aqueous solutions 

 of sodium hydro.xide are not inflected between 0° C. and 

 100° C. In each case the form of the curve appears to be 

 determined mainly by the rapid changes of viscosity which 

 accompany changes of temperatures. Moderately dilute 

 solutions give curves that are inflected between 0° C. and 

 100° C. ; the temperature of inflection reaches a minimum, at 

 48° C, in the case of a normal (4 per cent.) solution, but 

 rises to 100° C. when the concentration is raised to 30 per 

 cent. 



(2) The inflected conductivity-temperature curves can be 

 represented by the formula 



This formula is applicable to conductivity-temperature curves 

 of all kinds, and gives expression, not only to the inflection 

 now under consideration, but also to the maximum con- 

 ductivity and the second inflection in the general con- 

 ductivity-temperature curve. - 



(3) The maximum conductivity of caustic soda at 18° C. 

 is 03490 in a 15 per cent, solution, the value given by 

 Kohlrausch being 03462. At higher temperatures the 

 maximum conductivity is considerably greater, rising to 

 more than 1.4 at 100° C, and occurs in solutions of greater 

 concentration. 



(4) The viscosity of a 50 per cent, solution of sodium 

 hydroxide is approximately seventy times as great as that of 

 water. The influence of this factor may be to some e.xtent 

 eliminated by dividing the molecular conductivity by the 

 fluidity, and this ratio it is proposed to call the " intrinsic 

 conductivity " of the solution. Whilst the molecular con- 

 ductivity of sodium hydroxide solutions decreases steadily 

 as the concentration is increased, the intrinsic conductivity 

 falls to a minimum at about 8 per cent. NaOH, and then 

 rises, until at 50 per cent. NaOH, the value is considerably 

 greater than in the most dilute solutions. It is believed 

 that this increase is due to the fact that liquid soda is an 

 electrolyte, per se, and that, in concentrated solutions, the 

 current is conveyed partly by the soda alone, as if it were 

 in the fused state. 



(5) In re-determining the densities of aqueous solutions 

 of sodium hydroxide, quantities of sodium, amounting to 

 about 150 grams at a time, were weighed, and converted 

 quantitatively into concentrated solutions of sodium 

 hydroxide by the action of steam in a platinum vessel. 

 Eleven determinations, made with six different standard 

 solutions, gave, as the density of a 50 per cent, solution 

 at 18° C, the value 1-5268, with an average error of ooooi. 

 Solutions of known concentrations having been prepared by 

 dilution, their densities were determined with a probable 

 error of not more than ooooi : the values recorded by 

 previous observers were derived from solutions standardised 

 bv titration only, and appear to contain errors in the third 

 or even in the second place of decimals. 



(6) In the formula 



p, = Pi) + <U + Bt- + yfi. 

 which represents the influence of temperature on the density 

 of water and aqueous solutions of soda, the coefficient of t' 

 vanishes when a concentration of 12 per cent. NaOH is 

 reached, whilst the coefficient of t' vanishes at 42 per cent. 

 NaOH ; at the latter concentration there is a simple linear 

 relationship between density and temperature. 



(7) The molecular volume of sodium hydroxide in dilute 

 aqueous solution has a large negative value, a litre of water 

 dissolving 140 grams of sodium hydroxide at 0° C, 100 

 grams at 18" C, or 60 grams at 50° C, without in- 

 creasing in volume. The molecular volume does not in- 

 crease continuously as the temperature rises, but reaches a 

 maximum value at about 70° C. In a 50 per cent, solution 

 the temperature has little effect on the molecular volume, 

 the extreme variation being only about 10 per cent. 



1 Compare Roy. Soc. Prac, 1922, vol. l.-cxi. pp. 42-54. 

 - Loc. cit., p. 52. 



NO. 1832, VOL. 71] 



