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fore adjusted until, with the required negative in position, there is no change in the deflection of the galvanometer on turning the shutter. The method is extremely accurate. If the opacity of the negative be 10, cutting the light-intensity down to 1/10th of its value so that the density, or logarithm of the opacity, is 1, extreme readings differ by 0.002 per cent. For a density of 5 the difference is less than 0.01 per cent. A Method of Measuring very Small Capacities, by L. HARTSHORN, A.R.C.S., B.Sc., D.I.C.

A Demonstration of A New Form of String Galvanometer was given by PROF. ERNEST WILSON.

A Demonstration of The Phosphorescence of Fused Transparent Silica was given by DR. W. E. CURTIS, King's College.

The phenomenon, to which attention has been called by various observers, was demonstrated, using a mercury lamp and a hydrogen tube, both of transparent silica. The effect of heat in increasing the intensity of the phosphorescence and decreasing its duration was also shown.

Observations made on a silica tube containing helium and a very slight trace of hydrogen were described. It was found

that whereas a condensed (oscillatory) discharge gave the Balmer lines faintly and feeble phosphorescence, an uncondensed (unidirectional) discharge developed neither Balmer lines nor phosphorescence. There

was also a correspondence between the localisation of the Balmer lines and that of the phosphorescence. On admitting hydrogen to the helium tube by heating it red hot in a blowpipe flame, the phosphorescence was obtained strongly. These observations suggested that the effect might be due to radiation of wavelengths occurring in the hydrogen spectrum, but absent from the helium spectrum, and it was pointed out that the hyman series of hydrogen, which lies between XX 1,215-912 A, was probably the effective radiation, since there are in this region no helium lines. Some support

is lent to this view by the fact of the strong absorption of quartz in the region in question, the centre of its absorption band being situated at about A 1,050 A. The other

gases whose radiations are effective in producing phosphorescence are also believed to give rise to lines in this region.

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NOTICES OF BOOKS.

A Textbook of Inorganic Chemistry, Edited by J. NEWTON FRIEND, D.Sc., PH.D., F.I.C. Vol. 2: The Alkali Metals and their Congeners, by A. JAMIESON WALKER, PH.D., B.A., F.I.C. Pp. XXVI. + 379. London: C. Griffin & Co., Ltd., Exeter Street, Strand. 1924. Price 20s. Volume 2 of Dr. Friend's Textbook of Inorganic Chemistry is devoted to the alkali metals and their congeners, and has been written by Prof. Walker.

The occurrence, history, preparation, properties (chemical and physical), atomic weight determinations, compounds, detection and estimation of each of the elements (and the radicle NH1) are described in order. The latest information has been included, and there are extensive references at the foot of practically every page. These, it is stated, have been checked by Mr. F. W. Clifford, librarian of the Chemical Society, and his assistants.

Hydrogen has been included in Group 1 of the Periodic Classification. The inclusion of this element has been the subject of much controversy since Mendeléef first proposed it in 1872. Reasons for placing it at the head of the halogen group have been suggested from time to time. Most of these, however, are simply arguments against its inclusion in Group 1, with the elements of which it certainly has decided resemblances. Loring has recently published in this Journal a Wedge Periodic Scheme, in which its relationship to the alkali metals is indicated without it being actually incorporated in this group.

It is to be hoped that the remaining volumes of the series will appear without undue delay, so that chemists may be able to refer to reliable information over the whole range of inorganic chemistry.

The attention of librarians may be directed to the reasonable price asked by the publishers for such a comprehensive work. J.G.F.D.

BOOKS RECEIVED.

Matter and Change-An Introduction to Physical and Chemical Science, by WILLIAM CECIL DAMPIER WHETHAM, M.A., F.R.S. Pp. VI. + 280. 1924. The University Press, Cambridge.

The U.S. Department of Commerce, Bureau of Standards, has issued the following bulletins :

Some Methods of Testing Radio Receiving Sets, by J. L. PRESTON and L. C. F. HORLE. Pp. 203 to 228.

Emissive Tests of Paints for Decreasing or Increasing Heat Radiation from Surfaces, by W. W. COBLENTZ and C. W. HUGHES. Pp. 171 to 187.

A Camera for Studying Projectiles in Flight, by H. L. CURTIS, W. H. WADLEIGH and A. H. SELLMAN. Pp. 189 to 202.

United States Government Master Specification for Coal Tar Pitch for Waterproofing and Damp Proofing. Pp. 2 to 11.

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216982-Bruni, G.-Process for the production of phosphoric derivatives of inositol. Abstract Published this Week. 214765-Amino anthraquinones.-Drescher, H. A. E., Thomas, J., and Scottish Dyes, Ltd., Murrell Hill Works, Carlisle. Anthraquinoneimides of dibasic acids tained by heating a halogen-anthraquinone with an imide of dibasic acid in the presence of copper and an acid absorber; the latter may be omitted when a metal salt of the imide is employed. The imides yield amino-anthraquinones upon hydrolysis, for example, with concentrated sulphuric acid; by partial hydrolysis of phthalimidoanthraquinones, o-carboxybenzoylaminoanthraquinones are obtained. According to examples 1-phthalimid anthraquinone is obtained from 1-chloran

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thraquinone and phthalimide with or without addition of nitrobenzene, and is hydrolysed with sulphuric acid to 1-aminoanthraquinone; changed halogen derivative may be removed at the hydrolysis stage by partially diluting the sulphuric acid solution and filtering; the following compounds are similarly obtained: 1:5-diphthalimido-, 1:5-diamino-, 1-chlor-5-phthalimido-, and 1-chlor-5-amino-anthraquinones from 1:5-dichloranthraquinone; 4-phthalimido- and 4-amino-1methylamino- 2 bromanthraquinone from methylamino-2:4-dibromanthraquinone; 1-phthalimido-2-nitro- and 1-amino-2-nitro-anthraquinones from 1-chlor-2-nitroanthraquinone; 1-amino-2methyl-4-phthalimido- and 1:4-diamino-2-methylanthraquinone from 1-amino-2-methyl-4-bromanthraquinone; 1-methyl-amino-4-phthalimidoand methylamino-4-amido-anthraquinones from 1methylamino-4- bromanthraquinone; 1-phthalimido-2-amino- and 1:2-diamino-anthraquinones from 1-chlor-2-amino-anthraquinone; 2-phthalimido-, 2-o-carboxybenzoyl-amino-, and 2-aminoanthraquinones from 2-bromanthraquinone; 1succinimido-anthraquinone and a partial hydrolysis product thereof from 1-chloranthraquinone and succinimide. The production of aminoderivatives from 1:8-dichloranthraquinone, 1chlor-4 or 5-nitroanthraquinone, and 1-chlor-4oxyanthraquinones is also referred to.

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.

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will Sell by Auction, in lots, at the above Works, on MONDAY, 28th July, and following days, at Eleven o'clock precisely each day,

CHEMICAL PLANT & MACHINERY, including Steel-Ball and other Grinding Mills, three sets Millstones, Mixers, Dressing Machine, Conveyors and Elevators, six Johnson's Filter Presses up to 66-chamber, an Oliver Continuous Filter, nine 60-inch Electric and Steam Hydro-Extractors, about 150 Lead-Lined Vats, Tanks and Backs, partly with coils and agitators; Vacuum Bottles, 100 tons Lead Piping up to 3 in., lead and metal Cocks and Valves, six cast-iron Mixing Tanks, 14ft. by 10ft. by 3ft. 6in. deep; Steel Tanks, Pans and Vessels various, about 250 Enamelled CastIron Pots, 50 and 80 gallons capacity, partly with stirring gear, set in wood tanks; wrought and cast Piping, Worthington Air Compressor and Receiver, numerous Worthington Steam Pumps, gun-metal Centriugal and other Pumps, three Waygood Lifts, up to 30 cwt. capacity; 26 460-volt D.C. Motors, up to 80 h.p.; two Dynamos, two 30ft. by 8ft. 6in. Lancashire Boilers (120 lb. w.p.), fitted Ferguson superheaters and Bennis stokers; two Bennis Coal Conveyors, Green's 520-Tube Economiser, Sturtevant Fans and Air Trunking, FurDrilling, Screw-cutting Lathes, Milling, Shaping and Screwing Machines; Forge, Smith's Tools, Woodworking

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Machinery, three Weighing Machines up to 20 cwt.; a 1-ton Overhead Electric Runway by Herbert Morris, Ltd., fitted Weighing Machine, erected on steel-framed superstructure 50 ft. high; Grafton's 30 cwt. Loco. Crane, two 10 cwt. Coal Grabs, 20 side-tip Wagons, Trolleys and Trucks, 100 tons Steel Joists, Chequered Floor Plates, Shafting; Driving Belts, General Stores, Office Furniture, Day Time Register, and numerous other effects.

Catalogues may be had of Messrs. FULLER, HORSEY & Co., Mechanical Auctioneers and Valuers, 11, Billiter Square, E.C.3.

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136, GOWER STREET, LONDON, W.C.1.

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