November io, 1904] 



NA TURE 



39 



he published a valuable work on embryology. About i860 

 he was nominated professor of physiology, and two years 

 later he was appointed to a newly founded chair of pathology. 

 He was also appointed consulting physician to Princess 

 Margherita, mother of the present King. Throughout his 

 career he worked hand in hand with his colleague Tommasi. 

 <iaetano Giorgio Gemmellaro was born at Catania in 1832. 

 At the age of twenty he produced his first paper on certain 

 volcanic minerals from Patagonia, and from then onwards 

 published papers almost continuously for fifty years. The 

 geological history of Sicily was almost made by him. He 

 was professor of geology and mineralogy at Palermo, a 

 member of the Accademia dei Lincei and of many other 

 academies of different countries, one of the " Forty " of 

 the Italian Society of Science, a Senator, and Knight of the 

 Order of Savoy. Prof. Giustiniano Nicolucci was born in 

 the island of Liri, and graduated in medicine at Naples in 

 1S43. Under Stefano delle Chiaje he developed a taste for 

 biological science, and in 1842 published his first paper on 

 the structure and functions of the human cerebral nerves. 

 During the political disturbances he left his country, and 

 three years later returned to practise medicine. The various 

 types of humanity with which he came in contact in his 

 profession attracted his attention to the study of anthro- 

 pology, which he continued to his last day. His researches 

 dealt with both historic and prehistoric anthropology, his 

 favourite theme being the prehistoric anthropology of Italy, 

 and especially of southern Italy. 



A NEW and revised edition of " Object Lessons in Elemen- 

 tary Science," by Mr. Vincent T. Murch^, has been published 

 by Messrs. Macmillan and Co.,. Ltd., in two parts at 3s 

 each. 



The " London University Guide and University Corre- 

 spondence College Calendar " for 1905 contains in a con- 

 venient form the kind of information required by a privatr 

 student desirous of taking a degree at the University ol 

 London. 



Mr. Hemming's book entitled " Billiards Mathematical! \ 

 Treated " has reached a second edition, which has just been 

 published by Messrs. Macmillan and Co., Ltd. In 

 appendi.x iii. of the new edition Mr. Hemming institutes .1 

 comparison of strokes played through and fine, and of the 

 margin of error in each case. 



Messrs. Whitt.^ker and Co. have published a third edition 

 of " The Optics of Photography and Photographic Lenses," 

 bv the late Mr. J. Traill Taylor. The short chapter on 

 lenses of Jena glass which was included in the last issue 

 of the book has been omitted, and one on anastigmatic 

 lenses, written by Mr. P. F. Everitt, inserted in its place. 



An authorised translation, by Dr. M. Ernst, of the presi- 

 dential address delivered by Mr. Balfour at the Cambridge 

 meeting of the British Association has been published by 

 Herr J. M. Barth, Leipzig, under the title " Unsere heutige 

 Weltansschauung. " Dr. Ernst has rendered the address 

 into fluent German, and has added a few short descriptive 

 notes — mainly of a biographical character — which will be 

 of interest to readers unfamiliar with the names of Newton, 

 Cavendish, Stokes, Maxwell, Kelvin, Rayleigh, and other 

 natural philosophers to which reference is made. In the 

 first note, on the foundation and objects of the British 

 Association, the list of sections should have included the 

 section of educational science. 



The " Notes on Shooting, with Instructions Concerning 

 the Use of Nitro-Powders," written by " An Expert," and 

 published by Messrs. Curtis's and Harvey, Ltd., has reached 

 NO. 1828, VOL. 71] 



an eighth edition. This little volume of 83 pages has been 

 completely re-written, and now contains a practical account 

 of the results of recent researches in sporting gunnery. 

 The actions of guns and gunpowder are based on the laws 

 of physics and chemistry, and the results which have 

 followed the application of the scientific method to the 

 problems in connection with this branch of technology have 

 been incorporated in the book. The volume provides 

 evidence that manufacturers are coming to realise that sub- 

 stantial advantages in their work follow an acquaintance 

 with results arrived at by the man of science. The six 

 chapters into which the book is divided deal with smokeless 

 powders and the methods of testing them, with patterns on 

 the distribution of pellets on the target, with cartridge 

 shooting, and aiming at moving objects. 



OVR ASTRONOMICAL COLUMN. 



.•VPPAR.'iTUS FOR MeASI^-RING THE \'EL0CITY OF THE EaRTH'S 



Rotation. — Prof. A. Foppl, of the Munich Technical High 

 School, has devised a new gyroscopic apparatus for measur- 

 ing the angular velocity of the earth's rotation. 



As shown in the accompanying figure, the apparatus con- 

 sists of a large top carrying at each end of a horizontal 



spindle an iron wheel 50 cm. {10-7 inches) in diameter and 

 30 kilograms (66-i lb.) in weight. This spindle is the axle 

 of a small electro-motor which is capable of turning the 

 wheels 2400 revolutions per minute. The whole framework 

 is suspended by three fine, strong steel wires to the ceiling 

 of the room in which the experiment is performed, and a 

 cross piece immediately under the centre of the axle dips 

 into a bath of oil, thereby deadening the subsidiary inter- 

 fering oscillations. The angle through which the whole 

 apparatus turns about its vertical axis is read off, on the 

 two scales shown in the figure, to about the tenth of a 

 degree. 



To perform the experiment the current is disconnected 

 from the motor, and the latter run as a generator for a 

 short period, when a reading of a voltmeter placed in circuit 

 enables the angular velocity of the revolving wheels to be 

 found. Knowing this, one deduces the moments of inertia 

 of the turning masses, and then by an equation which takes 

 for its arguments the combined moment, the constant 

 angular velocity of the wheels, the torsion of the trifilar 



