4o6 



NA TURE 



[August 27, 1896 



scale is, as far as I know, unique in the world's history, and it 

 is the very marrow of our splendid development. Each large 

 work has the greater jiart of its scientific staff — and there are 

 often more than lOO tiodores phil. in a single manufactory — 

 occupied, not in the management of the manfacture, but in 

 making inventions. The research laboratory in such a work is 

 only different from one in a university by its being more splen- 

 didly and sumptuously fitted than the latter. I have heard 

 from the business managers of such works that they have not 

 unfrequently men who have worked for four years without 

 practical success ; but if they know them to possess ability they 

 keep them notwithstanding, and in most cases with ultimate 

 success sufficient to pay the expenses of the former resuUless 

 years. 



It seems to me a point of the greatest importance that the 

 conviction of the practical usefulness of a theoretical or purely 

 scientific training is fully understood in Germany by the leaders 

 of great manufactories. When, some years ago, I had occasion 

 to preside at a meeting, consisting of about two-thirds practical 

 men and one-third teachers, I was much surprised to observe 

 the unhesitating belief of the former in the usefulness of entirely 

 theoretical investigations. And I know a case where, quite 

 recently, an "extraordinary" professor of a university has been 

 offered a very large salary to induce him to enter a works, only 

 for the purpose of undertaking researches regarding the practical 

 use of some scientific methods which he had been working at 

 with considerable success. No special instructions are given to 

 him, for it is taken for granted that he himself will find the most 

 promising methods ; only, in order to increase his interest in the 

 business, part of his remuneration has been made proportional 

 to the commercial success of his future inventions. From this 

 clear understanding of the commercial importance of science by 

 the directors of industrial establishments there science itself 

 gains another advantage. A scientific man can be almost sure, 

 if he wants in his investigations the help of such technical means 

 as only great works can afford, that he will get such assistance 

 at once on application to any work ; and the scientific papers of 



<">erman chemists very often contain acknowledgments, with due 

 thanks, of considerable help they have thus obtained. 



Besides these advantages for the development of scientific and 

 technical chemistry in Germany there exists another very 

 important factor — practical assistance from the Government. 

 Universities are in Germany affairs of the State, not of the 

 Empire, and in no other point has the division of the Fatherland 

 into many smaller countries proved itself to such a degree a boon 

 and a blessing. The essential character of the German univer- 

 sities, the freedom conferred by the independence of the numer- 

 ous universities, is never lost. There have been hard times 

 occasionally for the universities of one country or another ; but 

 some universities were always to be found where even in times 

 of hard oppression liberty of teaching and learning remained 

 complete and unaffected, and the spirit of pure unalloyed scien- 

 tific research was preserved and encouraged. So this palladium of 

 intellectualfreedom has never been lost; and it regained the former 

 influence as soon as the casual oppression ceased. In our days there 

 is among all the separate State Governments in Germany a clear 

 conviction of the importance of practical support being given 

 to pure scientific research. To take one instance, in order to 

 facilitate teaching and research in electro-chemistry (a recently 



■ developed branch of science) a suggestion by some leading 

 practical scientific men to the members of the Government was 



•sufficient. Upon such a suggestion a considerable sum of money 

 -was spent first by the Prussian Government for the endowment 



■of electro-chemical chairs and laboratories in the three "poly- 

 technic " colleges of that country. A short time afterwards it 

 was resolved to erect at one of the universities (Gottingen) an 

 institute for physical chemistry, and especially electro-chemistry, 

 in the shape of a building which has just been completed. At 

 the same time, other German countries have begun to grant to 

 their universities and technical colleges considerable sums of 

 money for similar purposes, e.g. the .Saxon Landtag alone has 

 unanimously voted half a million marks {= ;^25,chx)) for the 

 erection of a splendid laboratory for physical chemistry at 

 Leipzig. 



You will excuse my boasting about our German management 

 of this most important question of scientific education. It is no 

 blind admiration without criticism, for I know by practical ex- 

 perience the management in other countries, and I can compare 

 them. And it is only for the sake of science itself that I write 

 these lines. If they should help the spread of the conviction of 



the incomparable practical usefulness of every support given to 

 pure science, together with the recognition of the fact that the 

 latter can only grow in an atmosphere of liberty and confidence, 

 I should regard it as tending towards the progress of science 

 itself, and destined to exercise such an influence on scientific 

 progress as may be compared with the discovery of the most 

 remarkable scientific fact. 



THE HOMOGENEITY OF ARGON AND OF 

 HELIUM.'' 

 'T'^HE question of the homogeneity of argon has been discussed 

 by Lord Kaylcigh and one of us in their memoir on Argon 

 (Phil. Trans., A, p. 236, 1895). 1*"' at that epoch the data 

 were not sufficiently numerous to enable us to arrive at very de- 

 finite conclusions. The discovery of helium and the analysis of 

 its spectrum by Runge and Paschen (Sitzuitgsberichte d. Akad. d. 

 ll'issfiischafteii, pp.639 and 759, Berlin, 1895) lead to the thought 

 that this body may be a mixture of two gases. 



To elucidate this question we submitted these two gases to a 

 methodical diffusion, causing them to traverse a duct of porous 

 pipeclay submitted on one of its surfaces to the action of a 

 vacuum. We satisfied ourselves that we might thus effect the 

 separation of hydrogen and helium and that of oxygen and car- 

 bonic acid, and that, by measuring the rapidity of the descent 

 of a column of mercury introduced in the circuit of the apparatus, 

 it is possible to arrive at a good determination of the molecular 

 weight of various gases. We have then tried to separate argon 

 into two parts by a method analogous to the separation of liquids 

 by fractionated distillation. 



The quantity of argon was close upon 400 c.c. The gas was 

 then treated in the manner shown in the following scheme : — 



: diflTusible. 



i . . . . 



{ I : : : : ' 



{ i ; ; ; : ' 



I ■ . ■ 



I. 



Less diffusible. 



■ ■ 4 



h i 



NO. 1400, VOL. 54] 



We determined the density of the two extreme portions, and 

 found that the one which ought to be the lightest had the 

 density (O = 10) of I9'93, and the heaviest of 20'0I. The 

 separation, if it takes place, is therefore minimal. 



The same experiment executed with helium yielded other 

 results. The density of the specimen which passed first was 

 I •874, and that of the gas remaining in the apparatus 2 '133. 

 A great number of fractionations did not change these figures ; 

 even the spectra of the two specimens were absolutely identical. 

 Even the first bubbles of the lighter gas showed the same lines, 

 with the same intensity, as the last bubbles which remained 

 in the apparatus. There was no difference in fifty fractions. 



Lord Rayleigh has had the kindness to measure the refraction 

 of the two specimens of gas. Whilst the lighter gives the 

 figure O'i350 {atmospheric air = I), the heavier had a refraction 

 expressed by the figure o' 1 524. Now these two numbers have 

 a relation almost identical with the relation of the densities, 

 for— 



°'I350 ^ i;8H i„ 1^,^ „f i;87_4 



01524 2-IIO 2133 



Let us now consider what happens when we submit a mixture 

 of the two gases to diffusion. Let us take, e.g., a mixture of 

 hydrogen with an excess of oxygen. After a sufficient number 

 of operations we obtain pure oxygen on the one hand, and on 

 the other a mixture of I part of hydrogen with 4 parts of oxygen. 

 It will not be possible to separate this mixture into its consti- 

 tuents, on account of the equal diffusion of oxygen and hy- 

 drogen when thus mixed. The identity of the spectra of helium 

 prevent us from deciding which is the pure gas and which is 

 the mixture. Calculation establishes that if we suppose the 

 heavier gas is a mixture, the density of the lighter, supposed 

 pure, ought to be I '58. Helium, lastly, if it consists of a mix- 

 ture of two gases, is formed either of two gases of the densities 



1 A paper presented to the Paris Academy of Sciences on July 27, by 

 Prof. W. Ramsay and Dr. J. Norman Collie. (Reprinted from the Chemical 



