February i i, iqoq] 



NA TURE 



437 



Tiiic Meteorological Office has recently published an 

 Knglish edition of the report of the meeting of the Inter- 

 national Meteorological Committee at Paris in September, 

 1907. The consideration of the classification of meteor- 

 ological stations, and of the definition in a clear and 

 precise manner of the terms used for frozen aciueous 

 vapour, referred to the committee by the conference at 

 Innsbruck (1905), was postponed. Among the various sub- 

 jects discussed we may mention a proposal of the Rev. L. 

 Fror (Zi-ka-\vei) for a system of signals for communicating 

 to ships the information at present sent to sea-ports, &c. 

 After a long discussion a special commission was appointed 

 to report upon the question ; the same commission was re- 

 quested to report upon a proposal by Dr. Shaw for uni- 

 formity in the scale and projection of marine meteorological 

 charts. After an exhaustive discussion of questions raised 

 hy Dr. Shaw and Mr. Xakamura relating to mean values 

 of climatological data, the committee decided to request 

 directors of meteorological systems to enumerate the publi- 

 cations containing such information for long periods for 

 their countries. This resulted in the publication in the 

 present report of a very valuable appendix giving refer- 

 ences to such data. Special commissions were appointed 

 to consider proposals for the publication of new isothermal 

 charts (Prof. J. Hann) and daily weather reports for the 

 whole globe (M. Teisserenc de Bort). Dr. HcUmann's 

 proposal that a commission should be appointed to deal 

 more especially with the question of wireless telegraphy 

 was adopted. Dr. Shaw and Dr. Hellmann were re- 

 spectively elected president and secretary of the Inter- 

 national Committee in place of MM. Mascart and 

 Ilildebrandsson. Reports of commissions on terrestrial 

 magnetism, aeronautics, and solar physics are printed in 

 the appendices. 



.\ P.1PER on a practical method for the improvemrnt of 

 existing railway curves was read by Mr. W. H. Shortt at 

 the Institution of Civil Engineers on January 12. The 

 subject-matter comprises methods for the introduction of 

 transition curves for connecting straight lines with circular 

 curves, and also for connecting reversed curves at the 

 reversal of curvature. The paper should be of service in 

 pointing out the scarcity of such relieving curves on exist- 

 ing lines in this country, a defect which leads to damage 

 of both line and rolling stock, and also contributes in no 

 small degree to the discomfort of the travelling public. 



The claims of the propeller problem are advanced by 

 Mr. J. Hamilton Gibson in an article on the efficiency of 

 marine engines and propellers in the Engineer of 

 January 29. The power developed by marine turbine 

 machinery is measured by application of a torsionmeter, 

 by means of which the angle of twist of a measured length 

 of the propeller shaft is ascertained and taken as a measure 

 of the torque passing through the shaft. The necessity of 

 calibrating the shaft on which the instrument is to be 

 used is shown from the results of experiments on appar- 

 ently identical shafts, in which the value of the modulus of 

 rigidity was found to vary from 11,500,000 lb. to 

 12,500,000 lb. per square inch, a variation which would 

 introduce an error of nearly 9 per cent, had the same value 

 of the modulus been assumed for all. Mr. Gibson has had 

 great experience with torsionmeters, and makes some 

 useful recommendations. Torsionmeter shafts should be 

 periodically re-calibrated. The torque in turbine-driven 

 shafts is found to be remarkably steady, consequently there 

 is but small interference in the torsionmeter readings due 

 to torsional oscillations of such shafts. Methods of obtain- 

 ing the zero reading are described; this should be done at 



XO. 2050, VOL. 79] 



the commencement of each trial. Data obtained from 

 torsionmeter trials point to a marked inefficiency of the 

 small high-speed turbine-driven propeller as compared with 

 the large low-speed piston-driven screw, and Mr. Gibson 

 suggests the need for a trustworthy thrust indicator which 

 would indicate the amount of compression on the shaft, and 

 thus enable turbine-driven propellers to be compared direct 

 with piston-driven screws. Experiments on multiple-bladed 

 propellers are also suggested, the analogy of modern wind- 

 mills, fans such as the Sirocco, and many vaned water 

 turbines being cited. Meanwhile, trial-trip data alone are 

 available until some public-spirited firm takes upon itself 

 the responsibility and cost of carrying out experiments on 

 full-sized propellers. 



The Physikalische Zeitsclirift for January 15 reproduces 

 an address by Prof. M. Planck to the science students at 

 the University of Leyden on the unity of natural philo- 

 sophy, in which he dealt mainly with the recent tendencies 

 of theoretical physics, and pointed out how marked had 

 been the absorption by electrodynamics of branches of the 

 subject formerly distinct. In his own field of work he 

 dwelt at length on the greater precision which had been 

 introduced into the study of thermodynamics by the reduc- 

 tion by the late Prof. Boltzmann of the idea of entropy to 

 that of probability. From this, since the entropy of two 

 independent systems is the sum of their separate entropies, 

 while the probability of the two systems is the product of 

 their separate probabilities, it follows that the entropy of 

 a system is proportional to the logarithm of its probability. 

 Finally, Prof. Planck pointed out the directions in which 

 future advances will be made, and predicted much dis- 

 cussion of these fundamental questions, for, as he said, 

 " theorists are many and paper is patient." He pleaded 

 above all for conscientiousness in self-criticism and avoid- 

 ance of personalities in the controversies which must arise. 



We have received from Messrs. \^'. and J. George a 

 new simplified form of burette stand, which they designate 

 the W.J. Burette Stand. It consists of a stout upright 

 fastened to the usual form of base, both of w^hich are of 

 teak. The upright, of wood, has two permanently fixed 

 arms, which are 9 inches apart. The arms are placed 

 directly above each other, and are slotted so that a burette 

 can easily pass into them. In order to hold the burette in 

 position the wood at the sides of the slots is counter- 

 sunk in the form of a ring about half-way down its thick- 

 ness. To fix the burette in position two circular rubber 

 bands are placed over it at such a distance apart that they 

 will just rest upon the counter-sunk part of the arms. 

 There are no screws to turn or get out of order, and by 

 simply slipping the burette between the slots it falls into 

 position without any further adjustment. For elementary 

 students this is certainly a very simple stand, and one 

 which cannot get out of order. The stand was invented 

 and patented by the Rev. A. Wentworth Jones. 



Messrs. Jaeger and von Steinwehr have recently com- 

 pleted at the Physikalisch-Technische Reichsanstalt, 

 Charlottenburg, an exhaustive research on the silver volta- 

 meter, in connection with which comparisons of Weston 

 normal cells have also been made (Zcitschrift fiir Instru- 

 mentenkunde, November and December, 1908). These 

 two experimenters have arrived at the following con- 

 clusions : — (i) The weight of silver deposited in the volta- 

 meter does not, within the errors of experiment, depend 

 on whether the Rayleigh form or the Richards modifica- 

 tion is employed. The absolute measurements show a 

 difference of i part in 10,000, but it was not possible to 

 find a measurable difference in the exact relative measure- 



