would be of great interest, and would throw some needed light on the magnitude of the errors involved in the ordinary magnetic formulæ used in engineering.

Prof. S. P. THOMPSON, in reply to Mr. Skinner, said that in their experiments there was an immediate ageing of their magnets on the application of the field. With regard to Mr. Campbell's remarks, different materials would of course give different curves. A forged ring was used in the research, but the forging could not have had much effect on the curves obtained. They had not tested hollow magnets, but experiments had been made on magnets with holes in the ends and the results were similar to those obtained for solid magnets. He had not performed experiments with Robison ball-ended magnets, but the effect of magnetic material at the ends of a magnet was to reduce its self-demagnetising factor. Referring to Dr. Russell's remarks, he said the corrections he mentioned could be neglected.

Prof. S. P. THOMPSON gave an exhibition of the optical properties of combinations of mica and selenite films (after Reush and others) in convergent polarised light.

Mr. C. R. DARLING exhibited the following :An Experiment to illustrate the Temperature of Equal Density of Aniline and Water.-The density of aniline at 0° C. is 1038, and at 100° 0°945, the diminution in density between the two temperatures being practically constant. As the density of water at 100° is o'959, the temperaturedensity curves of the two liquids cross each other, showing an equal density at about 63°. By dropping aniline into water at atmospheric temperature, the superior density of the former is shown by the drops remaining at the bottom of the vessel; but when allowed to fall in water at about 80°, the drops of aniline sink until the temperature of the water is attained, and then rise to the surface. By taking a U-tube, with the communicating part of narrow bore, and placing aniline in one branch and water in the other, the aniline column is seen to be shorter at low temperatures; but on surrounding the U-tube with a water-bath and heating, the columns will be seen to be equal in height at 63°; whilst at higher temperatures the column of aniline is longer than that of water.

apparatus may be used as an ordinary bridge, or as a bridge with calibrated wire, it being possible to calibrate any wire by the aid of the others. It may also be used for the measurement of the E.M.F. of thermal junctions, constants of cells, &c., and all the ordinary purposes of a stretched-wire potentiometer.

A new form of Carbon-plate Rheostat, suitable for control of small electric furnaces.-The defect of the ordinary carbon-plate rheostat-difficulty of accurate control when consuming a large amount of energy-is overcome in this instrument by the use of four rows of plates, each 2 inches square, there being 22 plates in each row. Each set of plates is furnished with a separate adjusting-screw, and hence may be kept at different degrees of tightness. By means of simple connecting devices, the plates may be used in series or parallel as desired. This form of rheostat is found to be well adapted for regulating electric-tube furnaces, and for varying the current to any desired extent during the calibration of instruments, &c.

NOTICES OF BOOKS.

Thoughts on Natural Philosophy and the Origin of Life. By A. BIDDLEcombe. Third Edition. Newcastle-onTyne: R. Ward and Sons. 1908.

THE author of this pamphlet shows himself to be unhampered by conservatism of thought and undeterred by the magnitude of difficulties, and also, we are bound to confess, unfamiliar with the work of his predecessors in the scientific world. He claims to have presented his readers with a new key to the riddle of the Universe, but the most trustful will feel that this key is but poorly constructed to unlock the doors it should enable them to pass through. Platitudes in plenty are to be found scattered through the pages of the book, and many inadmissible generalisations and exaggerations, while some theories which have been suggested previously and, at accepted are stated as if they were the product of the any rate, provisionally author's own brain; for example, he appears to be unaware that the idea that the ether is a form of matter is not new. However, it is not impossible that some readers will find intellectual pleasure in following the author's argument, and will, perhaps, thus widen their conceptions of the structure of matter and the origin of life.

MEETINGS FOR THE WEEK.

sold, in which no provision is made for a cold junction, are avoided; and no damage ensues from dropping or rough usage, as in the case of pyrometers protected by porcelain or silica. The cap, when worn out, is readily replaced.

A combined Metre-bridge and Potentiometer, with new tapping-key device, for pyrometric and general laboratory work. The arrangement of this apparatus is that of an ordinary metre-bridge, with four gaps, but with 4 metres of stretched wire; so that 1, 2, 3, or 4 metres of wire may be used in a bridge test. Between each pair of wires is placed a groove, through which passes a rod of phosphorbronze on which the tapping-key slides. These rods are connected to a terminal at the side: hence it is not necessary to connect directly to the keys. The keys are furnished with two knife-edges, and may be depressed on to the wire on either side of the groove in which they slide, thus facilitating the finding of the balance-point. Each wire is furnished with an arrangement for tightening. The

MONDAY, 22nd.-Royal Society of Arts, 8. (Cantor Lecture). “Steam Turbines," by G. Gerald Stoney. TUESDAY, 23rd.-Royal Institution, 3. "Evolution of the Brain as an Organ of Mind," by Prof. F. W. Mott, F.R.S. WEDNESDAY, 24th.-Royal Society of Arts, 8. "Afforestation and Timber Planting in Great Britain and Ireland," by J. Nisbet.

THURSDAY, 25th.

Royal Institution, 3.

"Aerial Flight in Theory and

Practice," by Prof. G. H. Bryan, F.R.S.

Royal Society of Arts, 4.30 "Native Man in Southern India," by Edgar Thurston.

Chemical, 4. Annual General Meeting. President's Address, "Elements and Electrons."

Research," by A. Stanley Eddington, F.R.A.S. Physical, 5. "Production of Steady Electric Oscillations in Closed Circuits, and a Method of Testing Radiotelegraphic Receivers," by J. A. Fleming. "Effect of an Air Blast upon the Spark Discharge of a Condenser charged by an Induction Coil or Transformer," by J. A. Fleming and H. W. Richardson. "Action between Metals and Acids, and the Conditions under which Mercury causes Evolution of Hydrogen," by S. W. J. Smith. SATURDAY, 27th.- Royal Institution, 3. Properties of Matter," by Prof. Sir J. J. Thomson, F.R.S.

Royal Institution.-On Thursday next, March 25, at 3 o'clock, Professor G. H. Bryan begins a course of two lectures at the Royal Institution on "Aërial Flight in Theory and Practice. The Friday Evening Discourse on March 26 will be delivered by Mr. Arthur Stanley Eddington, on "Recent Results of Astronomical Research"; and on April 2 by Professor Sir J. J. Thomson, on "Electrical Striations."

NEWS

THE CHEMICAL NEWS.

VOL XCIX., No. 2574.

from the moment when the powdering was half completed to half-way through the period of accumulation. Naturally the first rapid variations can only be roughly investigated in this way.

Leakage of helium from this sample is still continuing, and it is intended to watch its future course.

It will be observed that the whole quantity which has

ACTIVE MINERALS.*

By the Hon. R. J. STRUTT, F.R.S., Professor of Physics, Imperial College of Science, South Kensington.

In a paper published in Roy. Soc. Proc., 1908, A., vol. lxxxi., p. 272, I showed that phosphatised bones and similar materials were notably radio-active, and that helium could be detected in them. The quantity of helium found was not, however, uniformly greater in the geologically older materials than in younger ones of equal activity. This was hypothetically attributed to escape of helium in certain cases. I desired if possible to obtain direct experimental

confirmation of this conjecture.

It would clearly be impossible to detect leakage of helium from materials such as the mineralised bones, even in a lifetime. For any chance of success it was necessary to have recourse to the ores of uranium and thorium, in which the quantity of helium is something like 100,000 times greater.

The method of experimenting was to place a considerable quantity of the ore (usually a kilo. or more) in a bottle, provided with an exit tube and stopcock, and connected to a mercury pump. The bottle was exhausted and the stopcock closed. After the lapse of a definite interval of time, usually a day or more, a small quantity of oxygen was admitted to the bottle and then collected through the pump, carrying with it any helium which had come off from the mineral. The oxygen was absorbed with melted phosphorus, leaving a small residue of helium, together with impurities. Any hydrogen present in the original gas, which may have been liberated by radio-active decomposition of traces of moisture, was burnt along with the phosphorus, and thus got rid of. The residue was transferred to an apparatus consisting of a McLeod gauge in connection with a reservoir containing charcoal. On cooling the charcoal with liquid air, helium was isolated, and the quantity could be measured. As a test of purity, the spectrum could be examined in the capillary measuring tube of the gauge, using external tinfoil-electrodes.

I was astonished at the quantity of helium observed in the first experiments. It exceeded anticipation by hundreds, or even thousands, of times. I shall not describe the experiments in the order in which they were made, but rather in that which seems to connect them best.

It was found that after a radio-active mineral had been powdered, helium was evolved from it, rapidly at first, then at a diminishing rate. The following observations illustrate this.

A quantity (337 grms.) of monazite from the Transvaal was powdered and passed through a wire gauze sieve of 120 threads to the inch. This took about one hour. Immediately afterwards it was put in a bottle and the air pumped out. The rate of evolution of helium in cubic millimetres per day per kilo. of material was as follows:Time (days).

0.031

0'59

1.6

2.6

4.6

10.6

33'0

Rate.

261

76.6

17'1

12.3

9'57

4'38 I'14

The first experiment was made as quickly as possible, helium being collected for one hour. Times are measured

* A Paper read before the Royal Society, January 21, 1909.

but an insignificant fraction (probably less than a 500th) of the whole quantity present. (This sample of monazite was very poor in helium, containing only one-tenth cc. per grm.).

Moss (Roy. Dub. Soc. Trans., viii., 153) has observed that quantities up to 1 per cent of the helium contained in a mineral can be liberated by grinding in a vacuum. The present observations show that this is but the first rapid stage of a long continued leakage of helium from the newly created surfaces. The view that heat generated in grinding is the important factor appears untenable; for in that case escape of helium should cease on cooling. tinues; in all probability, however, the period is prolonged: and since the majority of radio-active materials can only be obtained in the form of pieces which have been broken off from their natural home a moderate number of years back, any observations made upon them are inconclusive as to the rate at which helium escapes when they are undisturbed in their original surroundings.

It is uncertain how long this evolution of helium con

It was found, in fact, that pieces from the same stock of monazite, about the size of a lump of sugar, which had not been fractured since they came into my possession two years ago, evolved helium at the rate of 0'002 cmm. per kilo. of material per diem.

This rate, though quite insignificant in comparison with that exhibited by the powdered material, is much in excess of the probable rate of generation of helium by radio-active change. It follows that the present stores of helium could never have been accumulated had the present rate of evolution prevailed throughout the life-history of the mineral.

With a view to testing a mineral more nearly in its natural condition, experiments were made on thorianite, which occurs in gravels, in detached cubic crystals, washed out of their original matrix. This, too, showed a considerable leakage of helium (0.069 cmm. per kilo. per diem). Tests were made at intervals over a considerable period. The rate was found quite uniform, the volume of helium pumped out being proportional to the time of accumulation. A second collection, made immediately after the first, yielded scarcely anything. It is difficult to account for this large evolution of helium from a mineral so nearly in its natural condition. It was thought possible that an explanation might be found by supposing that the temperature of the laboratory (65° F.) was somewhat higher than that of the natural surroundings of the mineral. The latter must, however, be above the freezing-point; and i was decided to test experimentally the rate of evolution at that temperature. The bottle containing the mineral was kept in ice for some days; under these conditions the helium leakage was reduced to about a quarter of its value at the higher temperature (0.018 cmm. per kilo. per day). This is still greatly in excess of the rate of accumulation.

It seemed possible, though unlikely, that the mineral, when kept in a vacuum, lost helium which it would have retained at atmospheric pressure. To test this explanation, the bottle containing the mineral was left filled with oxygen up to atmospheric pressure. At the close of several days the oxygen was pumped out, and absorbed with phosphorus. The ordinary quantity of helium was obtained, the rate of escape being undiminished.

It was noticed that the surfaces of some of these crystals were somewhat weathered. With the idea that this might thorianite much fresher in appearance was tested. The determine the escape of helium, another sample of rate of evolution in this case was only o'o127, about one fifth of that observed with the previous sample.

The majority of minerals allow water to percolate through them. The effective superficial area must therefore much exceed the external surface.

It is probable that loss of helium occurs from the weathering of these interior surfaces as well as from the

external faces of the crystals. Abrasion of the external surfaces by comparatively recent rolling in water-courses may have produced some effect.

Under laboratory conditions the rate of escape of helium from minerals always far exceeds the rate of production by radio-active change. Therefore the conditions under which the life of the minerals has been mainly passed, deep down in the earth, where atmospheric agencies have no place, must be supposed more favourable to retention of helium, for otherwise the present accumulation could never have been formed. The observations here recorded leave little room for surprise that fossilised bones and other materials do not always contain as much helium as would be expected from their radio-activity and geological age.

A SIMPLE LECTURE EXPERIMENT TO ILLUSTRATE SIMULTANEOUSLY THREE STAGES OF OXIDATION.

By JOHN E. MACKENZIE.

It is well known that by heating lead peroxide, PbO2, it may be converted into red lead, Pb304; and the latter into itharge, PbO, by further heating. This may be simply and effectively shown in the following way :

Lead peroxide is sprinkled on to a flat-bottomed porcelain basin so as to form a thin layer. The basin, supported on an ordinary triangular tripod, is heated gently at first, and then strongly by the flame of a Bunsen burner placed

directly under it. After a few minutes the hottest part of the basin is found to be covered by yellow litharge, PbO; the hot part immediately above the iron triangle by red lead, Pb304, and the colder part beyond by unchanged lead peroxide, PbO2 (vide diagram).

The contrast between the yellow, red, and puce coloured areas is very striking, and the experiment is therefore one eminently suitable for lecture demonstration.

Chemistry Department,

University of Edinburgh.

A NEW RADIO-ACTIVE PRODUCT OF THE URANIUM SERIES.

By JACQUES DANNE.

A YEAR ago in Mdme. Curie's laboratory I undertook the separation and concentration of the uranium X contained in 20 kilogrms. of uranium nitrate. While thus engaged I discovered a new radio-active substance which appears to be the immediate parent of uranium X; I propose to give

this substance the name radio-uranium.

The following are the chief operations which were performed in order to concentrate the uranium X, and by means of which I separated this new substance :

I removed a large part of the uranium X contained in an aqueous solution of uranium nitrate by repeated precipitations of barium sulphate in the solution. The sulphates obtained were converted into carbonates, and after dissolving these carbonates in hydrochloric acid the ordinary analytical separations were performed. The hydrates resulting from this separation contained a small amount of iron, a larger amount of uranium, and in addition the greater part of the uranium X. The hydrates converted into nitrates were dissolved in acetone to separate the uranium from the uranium X, according to Schlundt and Moore's method. Under these conditions the uranium X and the nitrates are insoluble in acetone. However, a certain amount of uranium X may remain in the solution. To remove it the acetone solution was shaken with a small quantity of freshly prepared ferric hydrate, which fixes the uranium X in solution. The nitrates insoluble in acetone and the ferric hydrate were put together and thoroughly washed with acetone to in water, evaporated to dryness and ignited, were taken up remove all traces of uranium. These products, dissolved by a small amount of hot water to which a little hydrochloric

acid had been added.

The product A, insoluble in acidulated water, contained the uranium X; it had an activity equal to sixty-three times that of uranium, and weighed 0.5 grm. As for the product B, obtained by evaporating the liquid to dryness, it contained iron, had an activity equal to 0.51, and weighed o 4 grm.

In October last year I again examined all the products obtained by the above treatment. One fact in particular attracted my attention, namely, that product B had become ten times more active, and I decided to seek for the cause of this abnormal increase of activity.

After having successively eliminated the possible presence of a radio-active impurity belonging to the actinium or radium series, I was able to prove that this increase of activity was due to the formation of uranium X.

Thus I was able to separate a small quantity of uranium X from product B, and to study the laws of the variation of activity of each of the products resulting from the separation.

Product B dried at 150° was taken up with warm water; the insoluble part, consisting chiefly of iron oxide, formed product B.; the liquid was shaken with freshly precipitated ferric hydrate; the washed and dried hydrate formed product B2; finally the evaporation of the liquid to dryness gave product B3.

I determined the activity of these three substances as a function of the time. The following table summarises the results obtained during the last three months :

February, 1909.

I. 3. 5.

Activities. Dec., 1908. January, 1909. Products. 23. 28. 4. 8. 13. 20. 25. 28. BI 221 2 12 1'99 1'92 1.81 1.65 1'53 1'47 1'41 1*38 1*35 B2 1'50 128 1.03 0.91 0.78 0.64 0'54 0'50 0'44 0'41 0*39 B3 141 168 2.04 2.25 2.51 2.82 3.02 313 3.26 3.31 3.35 From these measurements it follows that products Bi and B2 have a decreasing activity and product B3 an increasing activity. Moreover, if the curve representing the logarithm of the activity of product B2 as a function of

A NEW METHOD OF MATHEMATICALLY HARMONISING THE WEIGHTS OF THE

Kremers, in 1852, "drew attention to the equivalents of several elements showing difference among themselves

KINDRED WORK,

AND SOME OBSERVATIONS CONCERNING THE INERT GASES AND SATELLITES.

By F. H. LORING.

IN presenting a new method of harmonising the elements, I purpose at the outset to refresh the mind of the reader by reviewing briefly the previous work. It will be seen that many ideas, advanced from time to time, are to some extent recognisable in the method I have devised.

Many workers in this interesting field have sought to arrange the elements in various ways, with the view to finding some plan or formula which would classify the elements according to their combining weights, or simply express their values by an equation. A considerable degree of success has been achieved, as will be seen from the following brief historic review of the subject.

Probably the first attempt to classify the elements according to their weights was made by Richter (17621807), who thought that the combining weights of the bases formed an arithmetical series, whilst those of acids formed a geometrical series. Prout in 1815, and Meinecke in 1817, regarded the weights as whole numbers and multiples or polymers of hydrogen. Since then others have worked on the same idea, and comparatively recent developments have given some interesting results.*

Döberiner (1817 and 1829) grouped a few elements in "triads." Gmelin, in his "Handbuch der Chemie" (1843), arranged the elements in two ascending rows which formed a broad faced V-figure. Over one limb he placed O, and over the other H, N being placed midway between the other two. F, Cl, Br, and I headed the O-limb, these standing side by side in horizontal alignment. S, Se, and Te formed the next row, and so on.

Pettenkofer (1850) regarded the weights as whole numbers, and, by the addition or subtraction of integers, obtained a series. He thought that similar elements formed an arithmetical series resembling the organic radicals, and Dumas, with a like idea in mind, in 1851 | formulated a law to the effect that those bodies having like characteristics will follow a sequence in weight and chemical properties, as instanced by Cl (gaseous), Br (liquid), and I (solid).t

* Bernoulli (Zeit. Electrochem., 1907, xiii., 551) regards the atomic weights as mean values, the elements being a mixture of polymerides of hydrogen, just as the vapour of sulphur is regarded as a mixture of molecules S, S2, S4, &c. The author calculates by thermodynamic recurring formula the combinations thus possible. The weights need not be integral multiples of H, since the apparent atomic weight of an element may be a kinetic mean value. He gives weights calculated to the third decimal place.

This principle I have recently extended to include molecular groups as shown by the following table, the regularities of which must be regarded, however, as fortuitous :

Gladstone, in 1853, published a paper "On the Relation between the Atomic Weights of Analogous Elements." He compares the atomic weights of elements with the molecular weights of organic radicals, and divides the elements into three broad groups :-(1) "Those having the same weight; (2) those whose weights form a geometrical series; and (3) those whose weights form an arithmetical series." Cooke, in 1854, arranged all the elements then known in six series, each of which he reduced to a general formula of this order :-8+ng; 4+n8; 8+n6; 6+n5; 4+n4; and 1+n3. The first group included O, F, ČI, Br, and I. Lenssen, in 1857, arranged the elements in triads, and obtained twenty groups. Strecker, in 1859, called attention to the following series :-Cr 26.2, Mn 27.6, Fe 28, Ni 29, Co 30, Cu 317, and Zn 32.5. Lothar Meyer, in 1860, observed (1) "if the elements be arranged in order of their atomic weights, there is a regular and continuous change of valency as we pass from family to family; and (2) "that the successive differences of elements in the same column are at first, approximately, 16, except Be, then they increase to about 46, and, finally, approach a number ranging from 87 to 90." De Chancourtois, in 1862, devised the "Telluric Helix," which is well known. The elements are arranged on a cylinder so as to trace a spiral. Supplementary helices are required to take all the elements. Newlands (1863-64) wrote as follows:-"If elements be arranged in the order of their equivalents, with a few slight transpositions, it will be observed that the elements belonging to the same group usually appear in the same horizontal line. It will be observed that the numbers of analogous elements generally differ by 7 or some multiple of 7." In other words, the members of the same group stand to each other in the same relation as the extremities of one or more octaves of music.†

Mendeléeff, in 1869, first published his Periodic System. This was to some extent foreshadowed by Lothar Meyer, Newlands, Dumas, and others. The work is too well known to need description here. Mills, in 1884, sought to express the atomic weights by the equation At. wt. = K-158*. K is practically the number of a series-15, 30, 45, &c.; x is an integer of variable magnitude according to the elements selected, while 8=0.93727. He divided the elements into 16 groups. Reynolds, in 1886 (see CHEMICAL NEWs, 1886, liv., 1), described a geometrical method of illustrating the Periodic Law by a