lampworking operations a short distance from the hottest zone. He showed that when pure hydrogen and air were used there was no clouding effect, and hence came to the conclusion that some impurity in the gas was an important factor in causing clouding. Further experiments showed that sulphur dioxide when present in the gas in more than a very small proportion, was the chief factor in producing this effect. Theoretical considerations also pointed to the probability of sulphur compounds being the cause of clouding, and some figures obtained by using Nernst's heat equation agreed very closely with the results obtained experimentally. In one experiment, pure sulphur dioxide was passed through a tube heated by a bunsen flame. No fogging occurred until

the tube had cooled.

The lecturer pointed out that the cure for the defect seemed to lie in the purification of the gas used. He referred to the work of Dr. C. Carpenter, of the South Metropolitan Gas Co., who passed the gas through an iron tube containing clay balls soaked in nickel salts. The reaction that followed was represented by the equation CS,3H,=CH ̧H2S.

In the course of the discussion that followed, Mr. W. W. WARREN remarked that one of the difficulties encountered in the use of the Westlake machine was the effect of sulphur in the working pot. A white splotch was produced on the glass which made the bulb unusable.

Mr. F. F. S. BRYSON, Physicist to the Glass Research Association, said that that Association had also been considering the same problem, and had been in communication with Dr. Travers on the matter. He exhibited a number of lantern slides in which the effect in question was well shown. Mr. E. A. Coad-Pryor, Mr. Marden, and Prof. W. E. S. Turner also took part in the discussion of the papers.

Owing to lack of time, the last paper on the agenda, namely, "The Shrinkage, Porosity, and Density of British Fireclays after Firing at 1500°," by Edith M. Firth, B.Sc., and Prof. W. E. S. Turner, D.Sc., was postponed to another meeting.

NOTES.

CATALYTIC DECOMPOSITION OF CHLORACETIC ACIDS.-Whereas catalysis gives cetones with acids, chlorinated cetones are not obtained with chlorinated acids. Whether thorine, kaolin, or bone black be employed, the mixture HCI, CO, CO2, and C, is produced with monochloracetic acid. With trichloracetic acid bone black gives, at 250° C., chloroform and CO2, chloral did not give chloroform with CO, as might have been expected.-Comptes Rendus, January 17, 1921. CHEAP MANURES FOR THE FARMER.-An important arrangement which will have considerable bearing upon prices and supplies of artificial manures next season has just been completed between the Phosphate Commissioners, in conjunction with the Ministry of Agriculture, and Mr. George V. Parker, acting on behalf of the South Wales Basic Slag Company, Ltd., which is closely allied with the well-known steel firms of Messrs. Baldwins, Ltd., and Messrs. W. Gilbertson & Co, Ltd. It will be remembered that the mandate for the administration of the Island of Nauru, for merly owned by Germany, was conferred upon the

British Empire, an Act of Parliament was ultimately passed by which the United Kingdom was entitled to 42 per cent of the yearly output of phosphate produced in the island. Mr. George V. Parker has acquired the whole of this allocation of 42 per cent of the output of phosphate rock from Nauru. Although the purchase price is not stated, the amount involved constitutes by far the largest transaction which has taken place in the history of the British fertiliser industry, the previous largest deal having been in Florida phosphate rock, which was purchased by the British Government during the war. It is anticipated that some 180,000 tons of high-grade phosphate rock will be shipped during each year, and the material will be delivered to various ports here, from which it will be distributed throughout the United Kingdom. By arrangements with the Ministry of Agriculture, a proportion will be sold next season as basic phosphate, at under 3s. per unit of phosphate of lime, delivered to farmers' stations. As the present quotations of phosphate of lime range from about 5s. to 7s. 6d. per unit, it would seem that the Government pledge of cheap phosphatic manures for the farmer, as the outcome of the acquisition of Nauru Island, is at long last going to be kept. The first consignments of phosphate rock from Nauru are expected to arrive in this country in June and July, and already one-third of the next six months' production has been contracted for.

6232-Angel, H. R.-Treatment and reduction of sulphide refractory, etc., ores. Feb. 24th. 6160-Carpmael, W.-Manufacture of ethylene derivatives. Feb. 23rd.

6313-Christenson, O. L.-Production of ammonium chloride in coking or distilling coal. Feb. 24th.

6446-Christenson, O. L-Method of producing ammonium chloride. Feb. 24th.

6521-Humphries, H. B. P.-Packing, etc., material for scrubbing and absorption towers distilling columns, etc. Feb. 26th. 6036-Imray, O.-Manufacture of mordant dyeing dye stuffs and chromium compounds thereof. Feb. 22nd.

Specifications published this Week.

158992-Kelly, A. A. and Jones, B. D.-Process for the preparation of alkali pentaborates direct from boron ores. 135854 Fleming, R.-Process for conversion of hydrocarbons into hydrocarbons of lower boiling point. 159054-Maass, O.-Process of separating aqueous and other vapours from liquids and solids for preparing dilute sulphuric acid. 159086-Sierun, S E-Process of producing oxide of aluminium from chloride of aluminium.

THE CHEMICAL NEWS.

VOL. CXXII., No. 3183.

DISINTEGRATION OF ATOMS BY a-PARTICLES.

By F. H. LORING.

THE following abstract should be of interest to readers of the CHEMICAL NEWS. In a recent communication to Nature (March 10, 1921, cvii., 41), Rutherford and Chadwick state: It had been found that the long-range particles were charged hydrogen atoms (CHEMICAL NEWS, cxviii., 311) which indicated that some of the nitrogen atoms were disintegrated by the a-particles. Recent improvements in the optical conditions have been made, whereby the counting of the scintillations on the zinc-sulphide screen has been made easier, and the results now obtained are considered more reliable. They had been able to show definitely that the H-atoms from nitrogen have a greater range than those from hydrogen. The H-atoms driven from the hydrogen molecule or from a hydrogen compound have a maximum range of 29 cm. of air, while the H-atoms from nitrogen have a greater range of 40 cm., giving a ratio of I to 14. The range of the bombarding a-particles | in these experiments was 7 cm. "This result shows that these particles cannot possibly arise from any hydrogen contamination."

Other elements were subjected to the a-particle bombardment with the result that long-range H-atoms were liberated from boron, sodium, fluorine, aluminium and phosphorus; but the number from boron and sodium was much fewer than from the other four elements. It had been found previously that the long-range Hparticles were not liberated from either oxygen or carbon dioxide molecules.

With solids, the bombardment was against a thin film of the element or its oxide. Observations of the number of scintillations were made through a thickness of mica corresponding to a distance of 32 cm, of air, and the results are said to be independent of the presence of hydrogen or any hydrogen compound in the material.

The following elements were bombarded, and they showed very little, if any, effect with an absorption corresponding to 32 cm. of air :-Li, Be, C, O, Mg, Si, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Sn and Au.

The gases O2, CO, and SO, were examined for H-particles. At absorptions less than 32 cm. of air no traces of H-atoms were obtained. Elements other than the foregoing have not yet been examined for particles having a range less than 32 cm, in air.

The particles from all the first-mentioned elements have a maximum range of at least 40 cm. The particles from aluminium have a surprisingly long range of 80 cm.

While there is no experimental evidence of the nature of these particles, except in the case of nitrogen, it seems probable that they are all H-atoms liberated at different speeds. Assuming the law connecting the range and velocity of the H-particles to be the same as that for the a-particles, it would appear that the energy of the

H-particles from aluminium is about 25 per cent greater than the energy of the incident a-particle. Rutherford and Chadwick remark "It is of interest to note that no effect is observed in 'pure' elements [those without isotopes, such as C, N, O and F] the atomic mass of which is given by 4n, where n is a whole number. The effect is, however, marked in many of the elements the mass of which is given by 4n+2 or 4n+3. Such a result is to be anticipated if atoms of the 4n type are built up of stable helium nuclei and those of the 4n+a type of helium and hydrogen nuclei.

"It should also be mentioned that no particles have so far been observed for any element of mass greater than 31. If this proves to be general, even for a particles of greater velocity than those of radium C, it may be an indication that the structure of the atomic nucleus undergoes some marked change at this point; for example, in the lighter atoms the hydrogen nuclei may be satellites of the main body of the nucleus, while in the heavier elements the hydrogen nuclei may form part of the interior structure"

The importance of this experimental work is of very far-reaching significance, especially in affording a powerful tool for investigating subatomic phenomena and revealing secrets which some years ago one would consider beyond the power of man to discover. The long-range particles from aluminium seem to show that we are on the track of setting free atomic energy on a larger scale than hitherto found possible.

Now that Aston has been able to isolate spectrographically some of the isotopes of the alkali metals by using a heated anode (Nature, March 17, 1921), we seem to be on the eve of clearing up one or two outstanding problems of chemistry and at the same time more definite knowledge of the atom itself is revealed. It would appear that lithium has isotopes of masses 6 and 7, potassium 39 and 41, rubidium 85 and 87. Sodium gives a single line answering to the atomic mass of 23. If no other mass is discovered sodium would then be known as a "pure" element.

In addition to the references given above, the following literature may be consulted: Rutherford, Phil. Mag., June, 1919; Proc. Roy. Soc., (Bakerian Lecture), 1920, xcvii, 374; Loring, CHEMICAL NEWS, 1920, CXX., 73, 181, 205; cxxi., 105. Aston's results in measuring the masses of isotopes are recorded in the foregoing papers by the present writer. See also CHEMICAL NEWS, 1920, cxxi., 315; cxxii., 8 ("isotypes" was a typographical error: it should read "isotopes").

THE INSTITUTE OF PHYSICS.-The Meeting to inaugurate the Institute of Physics will take place on Wednesday, April 27, 1921, at 6 p.m., in the Hall of the Institution of Civil Engineers, Great George St., Westminster, Sir Richard Glazebrook, K.C.B., President, will preside, and Sir J. J. Thomson, O. M., will deliver an Address. Mr. A. J. Balfour is expected to be present and extend a welcome to the Institute. Non-members of the Institute or of the Societies associated with it may obtain tickets of admission on application to the Secretary, 10, Essex Street, Strand, W.C.2.

then a thin crystalline shell, then a thicker shell of cement intersected by a portion of a very thin crystalline shell following the contour of the first for about a quarter of the way round its perimeter, and lastly, a crystalline casing. 0'2 carat.

7 A broken-off corner consisting of a black crystal interior surrounded by alternate shells of cement and diamond. Three more or less complete shells and four cement ones may be counted. 0'2 carat.

8. A flat fragment consisting of a crystal central portion surrounded by four concentric shells of about 05 mm. thick, two of light-coloured cement, and two of crystal. 3 carats.

9. A flat fragment broken from one end of what, to outside appearance, must once have looked like a cube of highly crystalline bort. A scraping of the broken face with a knife-blade indicates that it consists of numerous exceedingly thin successive overgrowths of bort and cement.

11. A pyramid consisting of half of a "rounded octahedron." The edges, where dodecahedral striations would emerge on ordinary diamonds, are here of cement. Rather it looks like a piece of octahedral cement with projecting grey crystal bosses on the triangular faces, thus inclining the form to that of the plus and minus tetrahedral twin. 08 carat.

12. An irregular lump of cement to outside appearance. When first seen it was pitted with small elongated holes as though it had been prodded with the point of a pen-knife. At the time of writing it is scored over much of its surface with deep meandering cracks which either are (and look like) shrinkage cracks, or were there all the time, but hidden by being filled up with cement which afterwards fell out. 2'7 carats

13. A fragment similar to No. 10, excepting that it has rather fewer shells, has an outer coat of shiny bort, and gives the impression that the fractured face showing the shells has been glazed over with a vitreous layer and polished. The outer contour is that of the cube carrying the usual well-defined square indentations. Unlike most hailstone forms, which cleave in the dodecahedral plane, the fractured face of this specimen lies in the octahedral plane. o5 carat.

Mr. J. Parry has kindly analysed two small diamonds carrying this cement crust. It was not possible to separate the diamond from the cement, consequently the specimens had to be treated entire. They gave only the familiar indication for iron, and a rather stronger one for magnesia. The actual proportions of these elements in the cement itself cannot, of course, be determined until a large enough sample can be procured separate. Meanwhile, it seems reasonable to infer that the comparative softness of the cement is due to the magnesia, seeing that a considerable admixture of iron with diamond (e.g., stewartite) does not diminish the hardness at all.

Suppose a model octahedron of glass to be split parallel to a pair of opposite faces into a number of thin lamina; next the lamina to be sealed together in their original positions by means of a transparent cement slightly harder (or slightly less solvent) than the glass; and lastly the edges of the octahedron to be abraded (or disolved) away. The layers of cement being more resistant than the glass will stand out in slight relief as the attack proceeds.

Next let the same octahedron of glass be split again into thin laminæ parallel to another pair of opposite faces and the ecmenting and abrading (or dissolving) process repeated. We shall obtain another set of layers protruding in relief and intersecting the first at a constant angle.

Finally, let the series of operations be repeated for laminæ parallel to the two other pairs of opposite faces. The whole octahedron will now be spaced out into a device of small octahedra, marking its faces with a network of flush interlacing equilateral triangles, showing in relief on the reduced edges.

Laminated diamonds are exactly like this. The laminæ are sometimes as thin as paper; more often they are in the vicinity of half-a-millimetre thick. They are not hemitropic. They alter the overall contour of a crystal very little, differing essentially in this respect from the macle, but on the other hand they modify the surface detail to some extent. The layers corresponding to the cement layers of the hypothetical glass model always protrude where they show themselves, and, as a rule, they may be easily felt with the fingernail or with the edge of a knife. A formal analogy will be found in the octahedral structure of iron meteorites, wherein kamacite stands for the glass, and the less easily dissolved taenite for the cement.

The lamina scarcely ever manifest their existence save on the well-developed somewhat coarsely rilled faces of the rhombic dodecahedron or tetrahexadron. On octahedron faces they are rarely seen, as also on the finely-grained rounded edges of the octahedron (which are embryo dodecahedron and tetrahexadron faces). On octahedron-dodecahedron combinations they may be traced all round a stone excepting where the octahedron faces interrupt. The intersections of the lamina with the octahedron faces, however, are often indicated by an array of indented triangles.

In the majority of cases only one set of parallel laminæ appear on any one diamond. When two sets appear, intersecting on a solution face, one set is nearly always much more prominent than the other. An examination of a great number of laminated specimens has only determined a very few-and some of these doubtful-with more than two sets of laminæ in one stone.

In Fig. II. I have attempted to depict a laminated octahedron-dodecahedron combination from Wesselton, showing two sets of laminæ. It is one of the rare cases in which the edges visibly cut the octahedron face. Though some relationship between the lamina and the indented triangles is shown, it is not so marked as in many other specimens, wherein, while the edges themselves are not visible, their course is traced out by rows of little triangles, all much of a size, in a row.