8o 



NATURE 



[September 25, 1919 



of the form : Work of ruplure/area of fracture raised 

 to a power n, gives closer agreement with the experi- 

 mental results than other formulae which have been 

 employed, n ranges from 117 to 1-41 for the Charpv 

 and Thenard results. Dr. Unwin considers, however, 

 that the results are too few for a safe generalisation, 

 and that further progress cannot be made until a 

 greater number of careful tests have been made with 

 bars of different sizes, the results of which are as 

 consistent with each other as those of Charpv and 

 Thenard, the value of whose 1917 paper it would be 

 difficult to overrate. 



An interesting description, with working drawings, 

 of a Michell thrust bearing appears in the Engineer 

 for August 29. This bearing has been made by 

 Messrs. Cammell Laird for H.M. destrover Mackay, 

 and was fitted to the port turbine, whilst the star- 

 board turbine had a thrust bearing of the ordinary 

 type. The pressures on these bearings were 549 lb. 

 and 120 lb. per sq. in. respectively, and it is interest- 

 ing to note that the oil discharged from the Michell 

 bearing was about 18° cooler than that from the 

 ordinary type. Another valuable point about the 

 Cammell Laird design is in the form of a thrust- 

 indicating device fitted to the bearing This consists 

 of a number of small hydraulic cylinders having rams 

 which bear against the abutment ring which carries 

 the thrust pads. By pumping oil into these cylinders 

 the rams force the abutment ring off its seat, and the 

 whole of the propeller thrust is then carried bv the 

 rams. Thus the pressure in the cylinders is a measure 

 of the thrust. On the trials of the Mackay the thrusts 

 registered were 59 tons and 56 tons respectively for 

 the port and starboard engines, and varied to 61 tons 

 and 47 tons when turning. Variations in speed were 

 also recorded by the thrust indicator, and give fair 

 curves on a graph. This device is likely to be 

 extremely valuable in solving problems of propeller 

 efficiency and resistance of ships by enabling experi- 

 ments to be carried out on the ship itself as well as 

 on tank models. 



Messrs. George Bell and Sons, Ltd., announce for 

 early publication a new "Card Test for Colour- 

 Blindness," consisting of twenty-four cards devised 

 by Dr. F. W. Edridge-Green. Mr. J. Reid Moir is 

 publishing through Mr. W. E. Harrison, the Ancient 

 House Press. Ipswich, a volume entitled " Pre-Palaeo- 

 lithic Man," in which will be given an account of the 

 flint implements discovered in certain Pliocene deposits 

 in East Anglia. The book will also contain chapters 

 dealing respectively with flint fracture, the ancestry 

 of the Mousterian palaeolithic artefacts, and the 

 Piltdown remains. Alessrs. Hodder and Stoughton 

 announce for appearance in their New Teaching 

 Series of Practical Text-Books " Chemistry from the 

 Industrial Standpoint," P. C. L. Thome; "The 

 Natural Wealth of Britain : Its Origin and Exploita- 

 tion," S. J. Duly; "Foundations of Engineering," 

 W. H. Spikes; "Chemistry and Bacteriology of 

 Agriculture," E. J. Holmyard ; "Applied Botany," 

 G. S. M. Ellis; "Everyday Mathematics," F. Sandon ; 

 "The Mathematics of Engineering," S. B. Gates; 

 "Mathematics of Business and Commerce," O. H. 

 Cocks and E. P. Glover; and "Geography of 

 Commerce and Industry," R. S. Bridge. The 

 list of announcements of the Oxford University 

 Press (Mr. Humphrey Milford) has just been issued, 

 and contains, among others, the following works : — 

 "Medical Science: .-Xhstracts and Reviews"; "Patho- 

 logy of War Gases," Dr. M. C. Winternitz; "United 

 States Forest Policy," J. Ise; "Fungal Diseases of 

 the Common Larch," W. E. Hiley; "Effects of the 

 NO. 2604, VOL. 104] 



Great War upon Agriculture in the United States 

 and Great Britain," ProL B- H. Hibbard; "Aris- 

 totelis Meteorologicorum Libri Quattuor, " Recensuit 

 Indicem Verborum .4ddidit, F. H. Fobes; "Jami^s 

 Tod's Annals and .Antiquities of Rajasthan," edited, 

 with an introduction and notes, by Dr. W. Crooke; 

 and "The Heart and the Aorta," Drs. Vaquez and 

 Bordet, translated by Dr. Honeij. A new series &f 

 books is to be brought out by the University of 

 London Press, Ltd., entitled "The Education of the 

 Future." It will be edited by Mr. Benchara Bran- 

 ford, who is writing an introductory volume on "The 

 Modern Philosophical Basis of Education." Other 

 volumes of the series will be "Psychology of the 

 Class," F. Watts, and "The Teaching of Geography," 

 Miss A. Booker. 



Re,4DErs of Nature interested in geology should see 

 the latest catalogue (No. 88, new series) of Messrs. 

 John Wheldon and Co., 38 Great Queen Street, 

 W.C.2, which contains the titles of upwards of two 

 thousand publications relating to geology and 

 mineralogy, conveniently classified under the main 

 headings of Geographical, General Geology, and 

 Economic (Mineralogy, Metallurgy, and Mining). 

 The catalogue is particularly strong in French ard 

 German works. 



OUR ASTRONOMICAL COLUMN. 



Comets. — Mr. H. Vanderlinden has computed the 

 following orbit of comet 1919c (Metcalf-Borrellv) 

 from observations on August 24 and 30 and Sep- 

 tember 5. It differs considerably from that already 

 published, but is evidently more accurate : — 



T = I9I9 Dec. 7-2721 G.M.T. 

 o) =185° 49' 37"1 

 S = i2o^ 59' i4"[i9'9"o 

 t = 46° 23' 3o".l 

 log ^ =0046698 



Epheineris for Greenwich Midnight. 



R.A. N. Decl. Log r Log a 



h. m. s. o / 



Sept. 28 ... S 12 8 10 50 01943 0-3221 



Oct. 2 



6 



IS 21 I!: 



0-1827 0-3173 



15 3° 49 6 48 0-1711 0-3127 

 10 ... 15 40 41 4 43 0-1594 0-3083 

 '4 ••- IS SO SS 2 37 0-1478 0-3041 

 The magnitude is 8-8 on October 2 ; brightening 

 slowly. 



Many naked-eye observations of comet i9i()b 

 (Metcalf-Brorsen) are reported, so the brightness 

 evidently exceeds the tabular value. No revis<;d 

 elliptical elements have yet been published. The 

 errors of the Copenhagen ephemeris are now quite 

 appreciable, so a little sweeping may be necessary to 

 find the object. 



The Future of the Transit Circle. — Mr. J. E. de 

 Vos Van Steenwijk has a paper on this subject in 

 the September Observatory. Some ardent supporters 

 of photography think that our transit circles might 

 be scrapped altogether. The paper reminds us that 

 fundamental places of the sun and principal fixed 

 stars are still needed, but they may safely be left in 

 the hands of a few observatories. Reference stars for 

 photographic plates must also be observed, but the 

 number required may be greatly diminished if por- 

 trait lenses with a large field are used for the photo- 

 graphs. The paper suggests two other useful fields : 

 (i) A meridian parallax Durchmusterung ; while the 

 individual results might not be very accurate, probably 

 a good many stars would be found that would repay 



