posed per pair of ions (in air), and calculated the decomposition to be 4'7 times greater than Duane and Scheuer found for water. Wourtzel later reported briefly the results of other reactions, namely, decomposition of ammonia, of nitrous oxide, and of carbon dioxide (Fourn. Russ. Phys. Chem. Soc. Proc.,1915, xlvii., 210, 493,494). In all these reactions Wourtzel finds the amount of reaction to be in excess of the ionisation.

A. Debierne (Ann. Phys., 1914, [9], ii., 97) has been led by the statistical disagreement found by Scheuer and by Wourtzel between ionisation and chemical action to reject the theory of ionisation put forward by the writer as the primary cause, and to substitute one based on the hypothesis that the passage of an a particle through a gas may thermally decompose molecules lying outside the path of its ionising effect. This view of thermal decomposition is not favoured by Wourtzel (loc. cit.) because in some cases he found reactions actually having negative temperature coefficients.

The difference between the conclusions drawn by the writer in regard to the role played by ionisation and those of Debierne, Scheuer, and Wourtzel, based on the Paris measurements, demonstrate the desirability of further experimental work to determine, first, whether the discrepancy lies in the data themselves, or in their treatment; and, second, whether the higher chemical values, if correct, are too great to be brought into accord with ionisation. In order to settle the first point it appeared advisable to make an exhaustive experimental study of the simplest possible case, such as the combination of hydrogen and oxygen gases, in order to establish thoroughly the laws governing the reaction under various conditions as regards volume of the reacting vessel, pressure of the gases, concentration of emanation, temperature, and variation of the proportions of hydrogen and oxygen. The results of this study are reported in the present paper. In the main the experimental method of Cameron and Ramsay has been used and found well suited for the purpose. The writer was able to profit by the experience of Cameron and Ramsay to improve the manipulative details somewhat, to which attention will be called later. Following the course of the reaction manometrically enables one to study the kinetics of the reaction thoroughly. The reaction between hydrogen and oxygen has been chosen because the products of reaction are continually removed, and the system maintains itself in a constant condition with respect to the composition of the gases being acted upon.

The kinetic equation earlier deduced by the writer (loc. cit.) for the data of Cameron and Ramsay has been confirmed over a much wider range than was formerly possible. By varying the size of the spherical reaction bulbs, experimental confirmation has also been obtained of the law of the average path of a-particles as applied to their chemical effect in such vessels. Briefly expressed, all the assumptions previously made by the writer in treating the Cameron and Ramsay data have now been verified by direct experiment, and show that the treatment was in every way justified. The disagreement, however, between the data of Cameron and Ramsay and of Scheuer has been found to be real, and must be decided in favour of Scheuer through a good agreement between his and the new results. The explanation of the discrepancy lies in the quantities of emanation reported by Cameron and Ramsay, which were not measured in loco, but calculated from the amount of radium employed and the time of accumulation, which apparently led to a considerable error through incomplete evolution or collection of the radium emanation.

2. Source of the Radium Emanation. The radium employed as a source of emanation was part of that produced in the co-operative work of the U.S. Bureau of Mines (Bull., 104, 1915, by C. L. Parsons, R. B. Moore, S. C. Lind, and O. C. Schaefer) and the National Radium Institute. 297 8 mgrms. of radium element in the form of bromide, protected by a nine-fold excess of

barium bromide, was dissolved in water containing 20 per cent of hydrobromic acid; the high percentage of the latter has proved somewhat disadvantageous on account of the liberation by the a-rays of so much free bromine. In later work the salt will be converted into chloride and only 5 per cent of hydrochloric acid employed in the solution.

The Duane apparatus for the purification of radium without the use of liquid air has been employed and given very satisfactory results (Phys. Rev., 1915, [2], v., 311). The pumps employed for the apparatus were the Gaede mercury pump and the Gaede preliminary oil pump. The latter was used not only to start the mercury pump, but in handling the mercury in the three reservoirs of the Duane apparatus, and also the mercury in the McLeod gauge.

the setting of the mercury at e. By means of a capillary tube, b, connection was made at a with the Duane apparatus. After thorough exhaustion through a, b, and c toe by means of the Gaede mercury pump the purified emanation was introduced into c and sealed off at b.

Electrolytically prepared hydrogen and oxygen were collected over mercury in a Ramsay gas pipette (Proc. Roy. Soc., 1905, A, lxxvi., 113; Trans., 1907, xci., 939) sealed on at j, from which the gas could be passed through g and later through f to c, where it mixed with the emanation. This arrangement avoids bringing the emanation into contact with any stopcock grease, which caused Cameron and Ramsay much trouble in their early experiments through the continued generation around the stopcock f of foreign gases which would rise into c and vitiate the manometric results. The gas mixture can be collected below f, either before or after the collection of emanation

mination of the atomic weights of the fractions were performed in exactly the same manner as in the fractionation of the chlorides.

The fractional electrolysis of this solution of the nitrates, using a diaphragm, was found to precipitate the hydroxides of the earths about four times as rapidly as in the chloride electrolysis. It was possible that the hydrogen set free at the cathode might reduce some of the nitric acid to ammonia, as was found to be the case when no diaphragm was employed. Careful qualitative tests of the solution after the ninth fraction had been removed failed, however, to show the presence of a trace of ammonia. The results of this fractional electrolysis of the nitrates are shown in Fig. 5 and Table V.

It will be noted that in this series of electrolyses the coloured earths erbium, holmium, and thulium were present in preponderating amount in the first four fractions and were probably accompanied by considerable amounts of yttrium, as is indicated by the relatively low average atomic weight of the earths in these fractions. The last fractions, however, consist chiefly of yttrium, mixed with small amounts of cerium and neodymium that also were concentrated at this point. The method yields, therefore, in the first fractions a rapid concentration of erbium that is nearly entirely free from the didymium group; and, in the later fractions, yttrium that is quite free from the coloured earths of the erbium group, but is accompanied by any of the didymium group that may have been

present in the original solution. It is interesting to note that the later fractions contained detectable amounts of cerium, although qualitative tests of the original solution failed there to disclose the presence of this element. To obtain further indication as to the efficiency of the method in the separation of the earths of the erbium and yttrium groups, the first four fractions given in Table V. were combined, and were converted into a neutral solution of the nitrates. The weight of the oxides in the solution was about 220 grms., the volume of the solution was 2300 cc., and the average atomic weight of the earths was 116 54. A cell measuring 21 cc. in diameter and 20 cm. in height was used for the electrolysis. In other respects the same apparatus was employed as before. Six fractions were obtained by electrolytic precipitation. The liquid remaining after the last fraction had been removed possessed high resistance and gave no precipitate with oxalic acid. The results of this fractional electrolysis are

Fraction 6 was nearly white.

rapidly. The oxides were light yellowish brown, and about the same colour. (b) Very dark brown oxide.

The eighth fraction, Table V., Fig. 5, showed a sudden rise in atomic weight, which was probably due to the concentration of neodymium in the later fractions of that run. With a view to ascertaining whether the method of fractional electrolysis might profitably be utilised in separating neodymium (and its group elements) from the erbium group, even when the amount of material is comparatively small, the oxides constituting the eighth fraction were converted to a neutral nitrate solution that contained about 45 grms. of rare earth oxides in 600 cc. of solution, and this was fractionally electrolysed in the same manner as before. Six fractions were obtained. The

results given in Table VII. and Fig. 7 again demonstrate the ease and rapidity of the separation of neodymium from yttrium and erbium.

The separation of the rare earths by the fractional precipitation of their hydroxides upon electrolysis of solutions of their salts at voltages considerably higher than the de composition values of the salts is probably due to the action of the hydroxyl ions, concentrated near the cathode, upon earths of different basicities. The hydroxide of the weakest base will first tend to form, and if the deposition

Summary.

1. The decomposition voltages of several neutral, normal solutions of salts of the rare earths were deter mined. The values were found to lie close together and to be in the neighbourhood of two volts.

2. Fractional electrolysis of a solution of the chlorides coloured earths in the earlier fractions, and of yttrium in of yttrium earths yielded rapid concentration of the the later fractions. A small amount of neodymium that was present appeared in the last fractions.

3. Fractional electrolysis, with a diaphragm, of a solution of the nitrates of these earths showed concentration of the earths similar to that obtained in the electrolysis of the chlorides. The rate of precipitation of the hydroxides of the rare earths from the nitrate solution was, however, four times as rapid as from the chloride solutions. No ammonium salts were present in the electrolyte at the close of the run.

4. Fractional electrolysis of a solution high in erbium, holmium, thulium, and yttrium gave, in a series of six fractions, no appreciable separation of the first three

earths one from another, but rapidly separated the three from yttrium.

5. In the fractional electrolysis of solutions of certain salts of the rare earths, the hydroxides of the earths are precipitated, under the conditions here described, in the order of the basicities of the earths. Rapid concentration of certain groups of earths is attained in short series of fractions.

The method is being further studied in this laboratory.

FEDERATION OF BRITISH INDUSTRIES.

A LUNCHEON was given at Princes Restaurant on Wednesday, the 2nd inst., by Sir Algernon Firth, a member of the Federation of British Industries, to His Excellency Liang Chi-chao and the members of his Mission.

Amongst those present were Mr. R. T. Nugent, Mr. Fitzjohn Oldham, Mr. C. Tennyson, Mr. Guy Locock, Mr. P. Lockhart, Sir W. B. Peat, Sir Robert Hadfield, Mr. S. Springer, and Mr. Henry Hobden, of the Federation of British Industries, and Prof. Carsun C. Chang (Professor of International Law at the Peking University), Mr. V. K. Ting (Head of the Department of Geological Survey in China), Mr. Singloh Hsu (Secretary to the Ministry of Finance), Mr. Weishin Yang (Member of the Board of Education), Dr. H. K. Fung, M.S. of Agr., Ph.D. (Expert, Ministry of Agriculture and Commerce and Technical Delegate of the Chinese Government to the Peace Conference), and Mr. S. G. Cheng (Publicist).

Sir ALGERNON FIRTH, in proposing the health of Mr. Liang Chi-chao, stated that Mr. Liang, who has occupied the high posts of Minister of Finance and Minister of Justice in former Administrations in China, is the acknowledged leader and exponent of those elements which tend towards the systematic and peaceful development of his country.

On the occasion of his visit to Europe he is the trusted emissary of the President of the Chinese Republic, and I understand that an important feature of his mission is to gauge the feeling which animates Western people in regard to his country. May I express at once my confident belief that Mr. Liang will carry back the conviction that genuine friendship and the desire to help are the characteristics of the British people so far as China is concerned?

I understand also that it is Mr. Liang Chi-chao's desire to expound, so far as is possible in the brief time at his disposal, the economic position in which China finds herself to-day, and perhaps to suggest in general terms the manner in which the nations of the West, and particularly Great Britain, may with advantage to themselves assist in building up a prosperous and stable condition of affairs in

China.

When we in the West speak of China few of us realise that here is a country containing four hundred millions of industrious people, occupying an area comparable in size with the whole of Europe. This vast territory with its teeming population offers almost illimitable possibilities for economic development. The Chinese claim the Empire existed 8-10,000 years. Prof. Pritchard, of Oxford, allowed that they existed 2500 years B.C. as an Empire; 130 B.C. they are recorded as having ravaged coasts of Caspian Sea. Great Wall erected 300 B.C. In more modern times, 1793, Earl of McCartney went to China and reported it had 4202 walled cities, 330 million people, army i million, cavalry 800,000; and the time cannot be far distant when of all the countries in the world China will offer the greatest field for the beneficent enterprise of the industrial countries of the West. I say deliberately beneficent enterprise, because it must be obvious that the real solution of all the trials and tribulations which afflict China lies in her economic emanicipation.

But in order that this economic development shall proceed smoothly and bring about the desired results, it is essential that the policy of the open door and equal opportunity for

July 11 1919

the trade and commerce of all nations in China shall be carried into effect. I am glad to be able to assure His Excellency that the Federation of British Industries has definitely and emphatically associated itself with this policy and that its efforts will continue to be directed towards that end.

Granted that we are to see this policy of equal opportunity upheld, there remains, in my opinion, one great consideration which will prove a determining factor in bringing about a peaceful and prosperous era in China, and that is the factor of co-operation. The old order in which China held herself aloof while foreign enterprise sought to force a footing beyond her coast-lines has passed away, and the tendency to-day is towards a great and greater measure of co-operation. I can conceive of no more useful form of co-operation than that represented by the combined efforts of the Chinese, with their great good sense, their unrivalled commercial sagacity, and their probity, and of the British, upon whose merits I need not dwell. England never had an idea of exclusive trading but a high reputation for honest goods and fair and straight dealings. Indeed I am glad to notice that AngloChinese co-operation is beginning to find shape in many directions, one of the latest evidences being, I believe, a proposal to form in Shanghai an Anglo-Chinese Club at which the business men of both nations will meet in friendly intercourse. All this is to the good. But we must look forward to an even greater measure of cooperation than that of which we have such promising indications to-day.

I understand that the Overseas Trade organisation of the Federation are giving careful attention to this very matter, and I hope that one of the results of their study will be the establishment of close and amicable relations between the Federation and important sources of intelligence in China.

In replying to the toast, His Excellency LIANG CHI-CHAO enlarged upon the great possibilities that await British industrial enterprise in China in actual co-operation with the Chinese themselves. The enormous resources of China in raw material offered an illimitable field for development, but Mr. Liang considered that with the vast changes in trade and transport conditions throughout the World that has been brought about by the War, the obvious solutions lay in working up these raw materials as far as possible in China itself. The desirability of such an economic policy has been quickly recognised by the Japanese, who at a time when Great Britain had her hands tied in Europe neglected no opportuity to establish industrial enterprise through the Republic. Mr. Liang mentioned that the Chinese have awakened to a realisation that foreign assistance was necessary to her social and economic well-being. They would be inclined particularly to welcome British co-operation during the period of their country's regeneration, for the name of Great Britain stood for efficiency and integrity, and in no circumstances implied a sinister political programme. This could not be said of all countries. His Excellency there. fore hoped that British enterprise would bestir itself and take a hand in the industrial development of China. It was, however, of the greatest importance to act without delay as others were in the field in search of monopolies. Mr. P. LOCKHART proposed a vote of thanks to Sir Algernon Firth for acting as host, and the proceedings then terminated.

CHEMICAL EMPLOYERS AND ROAD TRANSPORT.-The Chemical Employers Federation has just entered into an affiliation agreement with the Motor Transport Employers Federation in respect of those of its members who employ commercial motor vehicles. The Motor Transport Employers Federation is one of the three Employers' organisations represented on the Joint Industrial Council for the Road Transport Industry, of which Council Captain F. G. Bristow, 83, Pall Mall, London, S. W. 1, is the Secretary for the Employers.