George H. Gabb, F.C.S.: Eggs of the Powder Pest Beetle (Lyctus brunneus). (Exhibited for the first time.)

R. Ruggles Gates, M.A., Ph.D., F.L.S., F.R.M.S.: Comparison of Crossing Overstages in Lactuca and Enothera.

F. B. Gibbard: Arrenhurus caudatus. L. G. Gilpin-Brown: Legs of Syrphid Trophidia scita.

H. Goullee: Entomological Specimens. J. T. Holder, F.R.M.S., and Miss Holder: Eyes of Spider.

J. R. Leeson, M.D., F.L.S., F.R.M.S.: The Fall of the Leaf."

R. J. Ludford, Ph.D., B.Sc., F.R.M.S.: Keratin Formation (Cornification) in Cancerous Growth of Mouse.

J. A. Murray, M.D., F.R.M.S.: IronAlum Hæmatoxylin Preparations (27 years old).

J. C. Myles: Diatoms.

H. W. R. Room, F.R.M.S.: Marine Hydrozoa (Obelia geniculata), showing Development and Liberation of Sexual Gooids.

J. Smiles and F. Welch: The Elements of Dark-ground Illumination.

66

C. Tierney, D.Sc., F.L.S., F.R.M.S.:
The Horrors of War.

E. E. Warr: Living Diatoms.
TRADE EXHIBITS.

R. & J. Beck, Ltd.: New form Museum Microscope. New form Dissecting Microscope, with and without Greenhough Binocular. New Apertometer. Aplanatic Ring Illuminator. Focussing Dark-ground Illuminator. Aquarium Microscope. Various forms of Microscopes and Apparatus.

The British Drug Houses, Ltd.: Microscopic Dry Stains and Solutions. Mounting Media. Indicators and Buffer Solutions. Comparator Case. Microscope. Slides stained with B.D.H. Standard Stains.

Chapman & Alldridge, Ltd.: A NonAchromatic Microscope Sub-stage Con

stuffs Corporation, Ltd., of 70. Spring Gardens, Braddiley, J., and Hill, J., of Crumpshall Vale Chemical Works, Blackley, both in Manchester, and Anderson, E. B., Mill Heys, Hemyock, near Tiverton, Devon.

A

Acid wool and substantive dyes, dyeing with; azo dyes, forming on the material.-Cellulose acetate silk is dyed by means of aminoazo dyes containing one or more carboxylic groups but not sulphonic group, the amino group being diazotizable. The dyes may be diazotized on the fibre, and developed with the usual components. table is given, showing the direct shades and those deevloped with -naphthol, -oxynaphthoic acid, and p-aminodiphenylamine of the dyes obtained from the following components: m-aminobenzoic acid and o-anisidine, anthranilic acid, mtoluidine, -naphthylamine, 4-nitro-2-anisidine, or 1:2-aminonaphthol ether; anthranilic acid and o-anisidine; p-aminobenzoic acid and aminohydroquinone dimethyl ether; p-aminosalicylic acid and -naphthylamine; 5-acetylamino-2-amino-4methoxytoluene and oxynaphthoic acid, the product being hydrolyzed; m-aminobenzoic acid, p-xylidine, and m-phenylenediamine or -naphthylamine. The fibre is dyed in an aqueous dyebath, with or without the addition of weak acids or salts.

Messrs. Rayner & Co. will obtain printed copies of the published specifications and abstract only, and forward on post free for the price of 1s. 6d. each.

THE CHEMICAL NEWS,

VOL CXXVII. No. 3315.

ARE THE NATURAL GROUPINGS OF THE ELEMENTS AND THE SPECTRAL LINES OF HYDROGEN RELATED? PART I.

By F. H. LORING.

It seems probable from Bohr's theory of the atom that there is a place principle involved, for the electrons automatically take up definite orbits when they are displaced outwardly, and on returning to their proper orbits definite wave lengths are revealed in the line spectrum then emitted, thus involving equally definite orbits. This is at very extraordinary phenomenon, and Bohr's formulation of the action by the use of Planck's quantum energy relation stands out as one of the great achievements of science.

It is very curious that the orbits should occur in definite places as due to definite quantised energy emissions, hence the term 'place principle" stated above. There are, however, other phenomena involving a simi

Referring to The Chemical News, 1923, CXXVII., p. 225, the five natural groups and groupings were given as 7, 9, 13, 21, 43. The recent discovery of hafnium (= celtium, atomic number No. 72-there is a dispute as to priority of discovery of this element, so that one is facetiously inclined to think of it as "celtafnium") as an element closely allied to zirconium, by Coster and Hevesy (Nature, Jan. 20, 1923) makes it necessary to raise the "18 level" in the wedge table originally given in The Chemi cal News, 1922, CXXV., p. 386.

It will be seen that "17" then becomes a limiting number in the wedge system, so that hafnium may bear a secondary number 4 in order to complete the series to which it belongs to the limit 17. This will be made eivdent by referring to the table.

lar place principle as the present writer has touched upon in his book, "The Chemical Elements," published by Messrs. Methuen, and which is due to appear shortly. Mention may be made of several relative papers by the present writer, which appeared in this Journal under the title :-" Is there an element of zero atomic number?" In particular see this Journal, 1923, CXXVII., p. 225, and the references therein should be consulted.

The foregoing studies do not, however, bring out clearly the "principle" in question, but they do lead up to it. If it is now assumed that the wave-lengths of the five main lines of hydrogen give expression to five orbital places round the nucleus of the atom, in conformity with Bohr's work, then it may only be a step to regard the periodic table as made up of natural groups and groupings, as already discussed in these pages-see citations above-and that these groups represent similar places. An attempt is here made to show an exact connection between these two "place" ideas, but before doing so a brief elementary statement of the characteristic feature of the hydrogen emission lines will be given.

Balmer, in 1885, showed that these lines could be closely formulated, which leads to the following well-known calculation:

One is therefore driven to the supposition that there should be 4 elements immediately before hafnium, bearing secondary numbers 0, 1, 2, 3. This would raise the total number of elements in the large grouping to 47; but since the last wedge is incomplete from the view of limiting numbers, a blank should follow the place occupied by uranium of atomic number 92. This would

then raise the number to 48. The necessity of a lacuna of atomic number 93 was shown in a paper by the present writer in The Chemical News, 1922, CXXV., p. 309.

Now, plotting the numbers 7, 9, 13, 21, 48 against wave lengths of the a to e lines of hydrogen, taken as the main lines, gives a straight-line curve as depicted in the accompanying diagram, which is, by the way, carefully drawn, showing that the intersec