the wheel, enabling the effect of each light to be seen in turn through the eyepiece.

The Rev. T. C. PORTER expressed his interest in the instrument, and said there was no doubt that the flicker photometer measured intensity independent of colour. The results obtained directly from a flicker photometer agreed with those deduced by indirect methods from observations with ordinary instruments.

Mr. L. GASTER expressed his admiration for the photometer, and explained that this type of instrument was becoming more important because of the great number of improvements made during the last few years in the manufacture of incandescent lamps and arc-light carbons by the addition of other substances to the pure carbon. A great step towards the simplification of the process of photometry had been attained by Prof. C. P. Mathews, by the aid of whose photometer one is enabled to get in one reading an illumination upon the screen, proportional to the mean spherical intensity of the source.

Dr. W. WATSON said the authors had compared a red light with a white light, and also a blue light with a white light. He asked if they had compared a red with a blue directly, and if so, how the results agreed with those deduced from the comparison of both with a white light. Mr. W. DUDDELL asked what was meant by the equality of two lights of different colours. Was it judged by the eye, the bolometer, or the flicker effect? On account of the Purkinje effect the inverse square law could not be used, and he asked for the real fundamental relation underlying the use of the instrument.

Mr. J. ABADY, replying on behalf of the authors, said the discussion had turned mainly on two points :-(1) Does the instrument measure candle-power? and (2) is it independent of the Purkinje effect? If a Bunsen disc were taken and used to compare the candle-powers of two lights of the same colour, the grease-spot vanished at a certain point. If a flicker photometer was substituted for the Bunsen disc, the flicker disappeared at the same point. In both cases candle-power had been measured. In reply to Prof. Ayrton he said that results obtained from the photo meter by different observers agreed among themselves and also agreed with results obtained from the Bunsen disc photometer. With regard to the Purkinje effect, he did not think it affected the readings of a flicker photometer, because the same values for the ratio between the intensities of two different coloured lights were obtained by varying the distances of the lights from the instrument within wide limits. Answering Dr. Watson, they had carried out the experiments suggested, and the results from the direct and the indirect comparison were in absolute agreement.

Mr. ROLLO APPLEYARD exhibited a Conductometer, the theory and mechanical details of which are fully described in the Proceedings of the Institution of Civil Engineers, vol. cliv., Session 1902-3, Part IV.

near the other end are constrained to move transversely, the phenomenon of polarisation can be illustrated. If the balls are put in neutral equilibrium, by supporting them on the upper ends of vertical rods, when suspended by spiral springs which very nearly balance their weights, the reflection of both transverse and longitudinal waves at surfaces of infinite and zero density can be illustrated. By substituting, for some of the vertical rods, vertical rectangular frameworks with heavy pendulum - bobs hanging from the upper sides, the phenomenon of anomalous dispersion can be exhibited.

NOTICES OF BOOKS

Liquid Fuel and its Combustion. By Wм. H. BOOTH. Westminster: Archibald Constable and Co., Ltd. 1903. THE first part of this book deals with the theory and principles of the subject, and the second with their application to practice. This latter part describes in detail the various systems adopted in using liquid fuel at sea, for stationary purposes and for locomotives; the Holden system as used by the Great Eastern Railway naturally occupies an important place, but those employed in other countries are not by any means neglected. The analysis by Mr. Horace Allen. The author in the preface has foreof flue gas is discussed in a chapter which has been revised stalled the obvious criticism regarding the omission of the consideration of some aspects of the subject which might possibly the requirements of readers will justify his selection have been expected to be found in such a treatise, and in most cases; the practical impossibility of including in fuel will explain the selection of types only of apparatus. one volume the description of all methods of utilising liquid The earlier part on the theory and principles is less satishardly seem to have much bearing on the subject, are factory. Some elementary details, which, moreover, treated in a misleading manner, as in the pages dealing with heat and temperature, and nowadays it can no longer be stated as an axiom that the scientific man rejoices at the specimen of what results when those to whom science is inutility of the discovery he has made. Judging by this caused by the neglect of important industrial methods by "less familiar, but more attractive," step into the breach scientific men, their efforts are not likely to be attended with enough of success to make it appear advisable to recommend the practice to others in the same category.

Manuel Guide de la Fabrication du Sucre. ("A Manual on the Manufacture of Sugar"). By R. TEYSSIER. Paris: C. Naud. 1903. THIS handbook does not aspire to be a complete treatise on the manufacture of sugar, but aims at describing in as simple language as possible the ordinary appliances to be found in a factory, with the methods of using them, and the means generally adopted to obviate difficulties and remedy

The model consists of a series of brass balls suspended in a line by spiral springs and capable of transverse or up and down motion. The balls can be set in vibration by releasing them from extreme positions by means of triggers, one set of triggers controlling the up and down motion, and another set the pendular. If the vertical and transverse periods are unequal, the release of the triggers in rapid succession produces a disturbance similar to that produced by the passage of light through a crystal. If

very meagre attention, and the book will be found more useful by foremen and works managers than by chemists. The advice and hints given are all thoroughly practical, and the author has evidently had considerable experience in the management both of workmen and machinery. A great deal of the matter, however, would seem to be better and more easily learnt in the factory itself than from the best text-book ever written, though, on the other hand, a good many useful suggestions might be gathered from the pages which deal with the building of an ideal sugar plant

CHEMICAL NEWS, Dec. 18, 1903.

and its management. An appendix of very elementary mathematical results seems somewhat out of place in such a book, but the other tables are very full, and will be constantly found useful for reference.

The

Beiträge zur Chemischen Physiologie und Pathologie. ("Contributions to Chemical Physiology and Pathology"). Edited by Franz HOFMEISTER. Band IV. 9-11 Heft. Braunschweig: Friedrich Vieweg und Sohn. 1903. THE first article of this issue deals with the important question of the conditions of action of the fibrin ferment and its bearing on the coagulation of the blood. author, Dr. P. Morawitz, adopts Alexander Schmidt's views, and endeavours to explain the discrepancies between them and those of later investigators; but he cannot be said to have done very much towards the elucidation of this obscure problem, though he has apparently subjected it to a careful investigation. Another interesting paper, by Dr. Otto von Fürth, describes researches on the behaviour of the oil in seeds during germination; in the course of the experiments it was hoped that some light would be thrown on the transformations which fat undergoes in the animal body. Although this hope was not realised the results of the experiments, which were carried out with the seeds of helianthus and ricinus, are very interesting. Most of the other papers are mainly concerned with physiological questions, and are not of much interest to the chemist.

305

more rapid and complete as the temperature is lower; (2) the phenomenon is assisted by the presence of mineral acids, even in so small a proportion as 1/10,000th; (3) it tends towards a limit, which in a neutral medium at 0° appears to be about 30 per cent.

MISCELLANEOUS.

:

Royal Institution.- The following are the Lecture Arrangements at the Royal Institution before Easter:A Christmas Course of Lectures (illustrated by lantern slides and adapted to a juvenile auditory) on "Extinct Animals," by Professor Ray Lankester. To be delivered on the following days at 3 o'clock :-Tuesday, Dec. 29, Thursday, Dec. 31, 1903, and Saturday, Jan. 2, Tuesday, Jan. 5, Thursday, Jan. 7, Saturday, Jan. 9, 1904,

Professor L. C. Miall, Fullerian Professor of Physiology, R.I., six lectures on "The Development and Transformations of Animals."

Mr. E. Foxwell, three lectures on "Japanese Life and Character."

Dr. E. A. Wallis Budge, two lectures on "The Doctrine of Heaven and Hell in Ancient Egypt " and "The Books

of the Underworld."

SOURCES.

NOTE.-All degrees of temperature are Centigrade unless otherwise expressed.

Comptes Rendus Hebdomadaires des Séances, de l'Académie des Sciences. Vol. cxxxvii., No. 20, November 16, 1903. New Preparation of Argon.-H. Moissan and A. Rigaut. The authors have already proved that the metal calcium combines easily with nitrogen at a dull red heat, giving a crystalline nitride of formula Ca3N2. As metallic calcium possesses also the property of fixing hydrogen at the same temperature, giving a crystalline hydride of formula CaH2, and this hydride does not dissociate at 500°, they now apply these different properties of calcium for the extraction of argon from the atmosphere. The process consists of four operations:-(1) The preparation of 100 litres of nitrogen; (2) the gradual enrichment of the argon in the nitrogen; (3) The first purification; (4) a second purification of the argon by circulation over calcium.

Exact Separation of certain of the Rare Earths.G. Urbain and H. Lacombe.-(See p. 295).

Acetylenic Acetones. New Method of Synthesis of the Isoxazols.-Ch. Moureu and M. Brachin.-The authors have previously established the fact that the acetones with acetylenic function R-CEC-CO-R give, on reaction with the hydrazins, pyrazols identical with those from which the 8-diketones are derived on hydration. They now investigate the action of hydroxylamine on the same compounds, and find that isoxazols are obtained, the yield being quantitative.

Retrogradation of Amidon Starch.-L. Maquenne. In a preceding research the author showed that amidon starch retrogrades with time; that is to say, becomes in part insoluble. This transformation is subordinate to a large number of independent variables, such as temperature, the nature of the medium, concentration, &c. He now investigates the influence of temperature and of the mineral acids employed in sufficient quantity to start saccharification. He finds (1) That retrogradation is

་

Shakespeare as

Mr. Sidney Lee, two lectures on Contemporaries knew him." Mr. J. A. Fuller-Maitland, three lectures on "British Folk-Song" (with vocal illustrations).

Mr. W. L. Courtney, two lectures on "Comedy-Ancient and Modern."

The Right Hon. Lord Rayleigh, six lectures on Physics."

During the Season 1904 the lectures on Tuesdays and Thursdays will be delivered at 5 o'clock, and the Saturday lectures at 3 o'clock.

The Friday Evening Meetings will begin on January 15, when a Discourse will be delivered by the Right Hon. Lord Rayleigh on "Shadows." Succeeding Discourses will probably be given by the Rev. Walter Sidgreaves, Mr. D. G. Hogarth, Mr. Alfred Austin, the Dean of Westminster, Mr. H. Brereton Baker, Mr. Alexander Siemens, Professor W. Stirling, Professor F. T. Trouton, Mr. Henry Arthur Jones, Professor Dewar, and other gentlemen.

The pre

The Electrolytic Preparation of Free Periodic Acid.-E. Muller and O. Friedberger.-The authors electrolysed a solution of iodic acid with an anode covered with PbO2. To estimate the HIO4 formed, in the presence of the remaining HIO3, they neutralised with soda until phthalein took a rose colour, added CO3NaH and KI, then with a titrated solution of As2O3 they estimated the iodine set at liberty; the weight of oxygen fixed by the As2O3 is a quarter of that contained by the HIO4. As for the total oxygen of the iodic and periodic acids, it is estimated by means of S203Na2 in solution acidulated with sulphuric acid and treated with potassic iodide. paration of HIO4 is effected in a small cell in which the porous pot contains the solution of HIO3 at 50 per cent, and an anode formed of a lead tube, traversed by a stream of cold water if necessary, and having its surface covered with a layer of electrolytic PbO2. The outer vessel contains a bi-normal solution of sulphuric acid, and a cathode consisting of two sheets of platinum. The details of the experiments will be found in the original paper; in one of them, after four and a-half hours electrolysis with a current of 2 ampères and 6 volts, equal to a density of current of 28 ampères per square c.m., the oxidation was complete. The solution in the porous pot is slightly brown and