New and Recent Publications AN IMPORTANT NEW SERIES Monographs on Industrial Chemistry Edited by SIR EDWARD THORPE, C.B., LL.D., F.R.S. Those who are responsible for organizing this valuable series may well be congratulated on this wealth of material illustrating the applications of recent scientific knowledge to modern manufacture."-THE LANCET. Organic Compounds of Arsenic and Antimony By GILBERT T. MORGAN, D.Sc., F.R.S., F.I.C., M.R.I.A., A.R.C.SC., Professor of Applied Chemistry, City and Guilds Technical College, Finsbury, London. 8vo. $5.00 net. "The work (Prof. G. T. Morgan's "Organic Compounds of Arsenic and Antimony") forms one of the admirable Monographs on Industrial Chemistry, now being issued. There is no need now for us to go to Germany for information on chemical matters when we have British literature of this high quality at hand."-MEDICAL PRESS. Edible Oils and Fats By C. AINSWORTH MITCHELL, B.A., F.I.C. 8vo, $2.00 net. Coal and Its Scientific Uses By WILLIAM A. BONE, D.Sc., Ph.D., F.R.S., Professor of Chemical Technology in the Imperial College of Science and Technology, London. 8vo. $7.00 net. The Zinc Industry By ERNEST A. SMITH, Assoc. R.S.M., Deputy AssayMaster, Sheffield. 8vo. $3.50 net. Colour in Relation to Chemical Constitution By E. R. WATSON, M.A., D.Sc., Professor of Chemistry, Dacca College, Bengal; Temporary Research Chemist with British Dyes, Ltd. 8vo. $4.00 net. The Applications of Electrolysis in Chemical By ARTHUR J. HALE, B.Sc., F.I.C., Demonstrator and The Natural Organic Colouring Matters By ARTHUR GEORGE PERKIN, F.R.S., F.R.S. E., F.I.C., Professor of Colour Chemistry and Dyeing in the University of Leeds; and ARTHUR ERNEST EVEREST, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; late Head of the Department of Coal-Tar Colour Chemistry, Technical College, Huddersfield. 8vo. $9.00 net. Catalysis in Industrial Chemistry By G. G. HENDERSON, M.A., D.Sc., LL.D., F.R.S., "Freeland" Professor of Chemistry, The Royal Technical College, Glasgow. 8vo. $3.00 net. Other volumes in preparation The Physical Chemistry of the Proteins By T. BRAILSFORD ROBERTSON, PH.D., D.Sc., Professor of Biochemistry in the University of Toronto. With very complete lists of Literature cited, and Indexes (authors and subjects). 8vo. 498 pages. $5.00 net. The book is a most welcome addition to the literature of the subject and will prove a valuable aid to the biochemist. Every student of the subject will feel grateful at finding here an account and discussion of the experimental material for which he must otherwise search the journals, together with useful tables and a bibliography. Dr. Robertson is himself a research worker in this field and has contributed largely to the present importance of this phase of the study.-THE NATION, N. Y. The Human Machine and Industrial Efficiency By FREDERIC S. LEE, Ph.D., LL.D., Dalton Professor of Physiology in Columbia University; President of the American Physiological Society; Consulting Physiologist to the U. S. Public Health Service; Chairman of the Sub-Committe on Fatigue in Industrial Pursuits of the National Research Council; Executive Secretary of the Divisional Committee on Industrial Fatigue under the Advisory Commission of the Council of National Defense. With 74 Illustrations. Crown 8vo. $1.10 net. Many of the facts presented in this book relate to war industries, but they are none the less pertinent as illustrating the principles enunciated; and the principles, it is hoped, will survive and receive attention long after the end of the war. Tables of Physical and Chemical Constants and Some Mathematical Functions By G. W. C. KAYE, D.Sc., The National Physical Laboratory, London; and T. H. LABY, M.A., Professor of Natural Philosophy, The University of Melbourne. 8vo. $2.25 net. Third Edition. X-Ray Atlas of The Skull By A. A. RUSSELL GREEN, M.B., B.S. (Lond.), M.R.C.S. (Eng.), Capt. R.A.M.C.T., Medical Officer in Charge of the X-Ray Department, 2/1 Southern General Hospital, Radiographer to the Birmingham Skin Hospital and to Birmingham Board of Guardians, etc. With 11 Plates (9 Colored): together with a Table showing relation between displacement of shadows and distance of bodies throwing those shadows. 4to. $3.50 net. LONGMANS, GREEN, & CO., 4th Avenue and 30th Street NEW YORK Compton Quadrant Electrometer (Developed by Drs. Karl T. and Arthur H. Compton, at Princeton University) For the measurement of very small currents or electrostatic potentials in connection with (a.) electronic currents (b.) radio-activity (b.) small capacities In construction, it resembles the Dolezalek design, except that it is much simpler and has a much smaller moving system and quadrants. A good working sensitivity is 0-20,000 mm. per volt with a period of 10 seconds, though higher sensitivities up to 50,000 mm. per volt are obtainable with proportionally longer period. For very low sensitivities it has a period of approximately 2 seconds. The instrument is dead beat, and its deflection proportional to the voltage applied. The high sensitivity is in virtue of employment of electrostatic "control," which acts against the restoring torque of the suspension, and is dependent on the nature of the disymmetry between the needle and the quadrants. Theoretically, infinite sensitivity could be secured with infinite skill in adjustment, though at the cost of infinite period. Its capacity is about 12 cm. The potential of the needle need not be raised above 30 volts, though a voltage as high as 300 volts is practical, and gives proportionately higher sensitivity. WE SUPPLY DRY CELL CHARGING BATTERIES in 4 sizes up to 144 volts, that are convenient, portable, constant, and well designed in construction. Four quartz suspensions are supplied with each instrument. QUARTZ FIBRES FOR GENERAL USE, CONDUCTING OR NON-CONDUCTING, calibrated and mounted in boxes are here offered for the first time. Further particulars in reply to your inquiry. We are the sole makers and distributors of the Compton Quadrant Electrometer PYROLECTRIC INSTRUMENT CO. Pyrometric and Electrical Precision Instruments 636-640 East State Street TRENTON, N. J. E. F. NORTHRUP, President and Technical Adviser Model 14-B Direct-Current HICKOK M Ammeters and Voltmeters THE BROOKS' INDUCTOMETER In the Brooks' Inductometer is offered a compact form of variable inductance, with a self inductance range of 5 to 50 millihenrys, possessing the following advantages: 1. A fair degree of astaticism, which tends to eliminate errors due to stray field effects. 2. It is less expensive and at the same time fully as accurate as the AyrtonPerry instrument. 3. It occupies less space than the Aryton-Perry form. The instrument has a very nearly uniform scale, obtained by properly proportioning the coils. It may be used as a mutual inductance. It has a good ratio of maximum to minimum inductance (about 9 to 1) and also has as high a time constant as is consistent with good design and moderate size. The instrument is fully described in Bulletin No. 152, a copy of which will be sent upon request. THE LEEDS & NORTHRUP CO. ELECTRICAL MEASURING INSTRUMENTS 4921 STENTON AVENUE PHILADELPHIA Tycos Temperature Instruments Indicating-Recording-Controlling Ther Mercurial, Recording and Mineral Oil Testing Instru- Aneroid Barometers APPARATUS FOR THE MANUFACTURE OF LIPOVACCINES AS USED IN THE ARMY MEDICAL SCHOOL IN THE PREPARATION OF Typhoid-Paratyphoid (A and B) and Pneumococcus (Types I, II and III) See Whitmore, Fennel and Petersen, "An Experimental Investigation of Lipovaccines," The Journal of the American Medical Association, February 16, 1918, Vol. 70, pp. 427-431, Whitmore and Fennel, March 30, 1918, Vol. 70, pp. 902-904; Whitmore, "Lipovaccines with Special Reference to Public Health Work," read at the December, 1914, meeting of the American Public Health Association; and Fennel, "Prophylactic Inoculation against Pneumonia," Journal of the American Medical Association, Vol. 71, No. 26. No. 25519 Triple Jar Bacteria Grinder, for manufacturing purposes Send for copy of Supplement 47 "Apparatus for the Manufacture of Lipovaccines " giving prices and detailed information regarding Pyrex Bacteria Grinding Jar, Steel Balls, Single, Triple, Sextuple and Duodeouple Jar Mills, Sharples Super-Centrifuge, Kolle Flasks, Ampoules and Vacuum Collectors for Bacteria ARTHUR H. THOMAS COMPANY IMPORTERS - DEALERS-EXPORTERS LABORATORY APPARATUS AND REAGENTS WEST WASHINGTON SQUARE PHILADELPHIA, U. S. A. SCIENCE FRIDAY, FEBRUARY 7, 1919 VARIABLE STARS1 THE speaker before such a gathering as this, in this eventful year, faces a dilemma in his choice of a subject. The topic which is foremost in all our minds is, beyond a doubt, the share which our comrades in science have had in carrying to a triumphant close the great work of the war-and an account of this would in some respects be the most suitable subject for a vice-president's address. But most of this work can not be described yet, if at all, for reasons of military secrecy; and it is still too early, in any event, to collect and correlate the records of the work of men who are still in the service, especially when almost the whole of the narrator's time has been spent in attempting, in a very humble way, to aid in the universal effort. I have therefore chosen the opposite horn of the dilemma, and propose to speak to you to-day upon a topic of pure science-removed perhaps as far as anything could be from the theater of war, trusting to whatever intrinsic interest the subject may possess to atone for the lack of timely interest, and the defects incident to hurried preparation. Variable Stars have been the objects of human wonder since the appearance of the Nova of Hipparchus led to the preparation of the first catalogue of the positions and magnitudes of the stars. The period of scientific observation of these changes may be dated from Tycho Brahe's observations of the Nova of 1572 and Fabritius' discovery of the periodic variation of Mira Ceti in 1596. For two and a half centuries after this date the number of known variables remained so small that they could almost have been 1 Address of the vice-president and retiring chairman of Section A-Astronomy-of the American Association for the Advancement of Science, Baltimore, December 27, 1918. |