December i6, 1909] 



N.-l rURE 



201 



Messrs. Gallenkamp and Co., Ltd., have favoured us 

 with a copy of their catalogue of spectroscopes, spectro- 

 meters, vacuum tubes, induction coils, and other accessories 

 essential to modern spectroscopical research. After 

 examining the publication carefully we recommend all who 

 are engaged or interested in such work to acquire a copy, 

 for it is plentifully illustrated, the instruments are described 

 ill detail, and instructions are given as to how they should 

 be set up for the best use in various researches. The 

 accessories for the production of spectra, such as tubes, 

 burners, coils, and cells, are very numerous, and the firm 

 makes a speciality of vacuum tubes to which we have 

 previously directed attention (vol. I.\xi., p. 448). The 

 " C " type of tube, in which the illuminated gas is viewed 

 end on in a capillary tube, without the interference of the 

 electrodes, is now made in Uviol glass and with ground-in 

 quartz windows, so that investigations of the ultra-violet 

 part of the spectrum may be carried out with the various 

 ultra-violet spectrographs figured and described in the 

 catalogue. 



Some results ^of trials of the new transmission gear for 

 marine turbines constructed for Mr. George Westinghouse 

 to the designs of Rear-.Admiral George VV. Melville and 

 Mr. John H. Macalpine appear in Engineering for 

 December 3. In this gear the reduction of speed from 

 5 to I is attained by the use of double helical spur wheels 

 and pinions mounted in such a manner as to secure an 

 even distribution of the bearing pressure between the teeth. 

 The full load to be transmitted is 6000 horse-power at 1500 

 revolutions of the pinion shaft, and a special hydraulic 

 brake was employed in the tests to take up the load. A 

 few of the results are given in the following table :— 



B. H. P. delivered by gear ... -171 

 H.H. P. of turbine .. .. 377 

 Efficiency, per ctnt yS' 



156 ... 4576 ... 5036 ... 54H6 ... 59:7 

 ■97 ... 4623 — 5> 8 ... 5567 ... 6o=;7 



This efficiency is very remarkable, being as good as has 

 been recorded with the best cut gears of ordinary 

 dimensions. An endurance test of the gear at full load 

 has also been carried out, extending from 3.15 on Saturday 

 afternoon until 7.15 the next Monday morning. During 

 the last thirty-four hours of the run the temperature of the 

 gear remained constant, and there was every indication 

 that the trial could have been extended indefinitely. The 

 performances of this gear on board ship will be looked for 

 with interest, both as regards the working of the gear 

 and the anticipated economy which will result by running 

 both turbine and propeller at their best speeds. 



The conditions of award of the prize of loooi. offered by 

 Mr. Alexander for a British-built aeronautical engine have 

 now been issued. We extract the essential conditions from 

 Engineering, as follows. The engine must develop not less 

 than 35 brake-horse-powcr, and not exceed 245 lb. weight ; 

 that is, 7 lb. per horse-power, including all parts necessary 

 for running, cooling apparatus, and accessories. .iVrms 

 suitable for bolting down to a testing bed are included in 

 the weight, and such arms must be arranged so that the 

 motor-shaft is not less than 16-13 inches above the test- 

 bed. The points on which the award will be given are: — 

 (■a) weight ■ and petrol consumption ; (b) trustworthiness 

 and steadiness^ of running ; (c) wear of working parts; 

 (d) security against fire; (<•). air-resistance offered by motor. 

 Each motor will be tested on, a 24-hours' run, and if the 

 stoppages during this time exceed three, or if the total 

 time of Stoppage exceeds thirty minutes, the motor will 

 be disqualified. The balancing wilf be taken into .con- 

 sideration, and the engine'.wjll.ajsb be tested at an inclina- 

 tion of 15 degrees, first one way and then the other, an 

 hour's run each way being given. A thrust of 175 lb. will 

 NO. 2094, VOL. 82] 



be applied during the tests to represent the thrust of the 

 propeller. The tests will be made in an air current of thirty 

 miles per hour. The regulations comprise subsidiary 

 details, but the above are the essentials. The tests will' 

 be carried out at the National Physical Laboratory under 

 the sole control of the advisory committee, and entries 

 may be made not earlier than February i and not later 

 than April 30 on entry forms which may be obtained' 

 from the secretary, advisory committee for aeronautics,. 

 Bushy House, Teddington. 



Messrs. Longmans, Green and Co. have published a 

 seventh edition of Prof. W. D. Halliburton's " Essentials- 

 of Chemical Physiology for the Use of Students." Scarcely 

 a page of the book has escaped revision, and a new lessori 

 on some typical organic compounds has been included in 

 the book. 



A THIRD edition of the " Elementary Treatise on Elec- 

 tricity and Magnetism," by Prof. G. Carey Foster, F.R.S., 

 and Prof. A. W. Porter, has been published by Messrs. 

 Longmans, Green and Co. The whole book has been re- 

 vised, and many additions have been made. The final 

 chapter has been re-written, and provides a good summary 

 of recent progress in electrical science. 



Mr. M. Kanade, Baroda, India, has sent us a copy of a 

 list of books he has compiled and classified according to 

 the system, known as the decimal classification and relative 

 index, devised by Mr. M. Dewey, director of the New York 

 State Library. The catalogue does not make it quite clear 

 how the books chosen for classification have been selected, 

 but the scheme provided for the classification of the works 

 in any library should prove useful. 



OUR ASTRONOMICAL COLUMN. 

 Daniel's Comet, igoge. — A second observation by Prof. 

 Daniel of the comet discovered by him on December 6 is 

 reported by a telegram from the Kiel Centralstelle, and the 

 following elements and ephemeris, computed by Dr. EbelL 

 from observations made at Princeton (December 7), 

 Northampton (December 8), and Nice (December 9), are 

 published in Circular No. 116 from the Kiel Centralstelle :=— 



Elements. 

 T =1909, December 5-6011 (Beilin). 

 o) = 8° i6-42'| 



/ =26 56 -go' J 

 logy = 0-1 9674 



Ephemeris i2h. {ALT. Berlin). 



,909 a i l°g -i I'.right- 



Dec. 13 ... 6 i8-i ... +39 310 -. 97S9 ■•• o'99 



15 ... 6 18-4 ... •f4i 62 



17 ... 6 1S7 .. +42 38-8 --• 9794 •■■ °'96 



19 ... 6 189 ... H-44 8-4 



21 ... 6 190 ... -4-45 347 ■-■ 9802 ... 092 



As the comet is travelling northwards through Auriga, 

 nearly parallel to the line joining 9 and /3 Auriga;, it will; 

 probably remain observable in the northern hemisphere for 

 some time. 



The above elements show a likeness to those of comet 

 1867 I., but are, as yet, too uncertain to permit of any 

 definite conclusions. 



It will be seen from the ephemeris that the comet is 

 now receding from the sun, and is becoming fainter ; 

 the unit brightness, at time of discovery, was given as ii-o. 



Halley's Comet, 1909c. — A further ephemeris for 

 Halley's comet, based on the assumption that perihelion 

 passage will take place at 1910 .Xpril 19-67, is published' 

 in No. 416 of the Observatory (December, p. 476), and' 

 extends to April 5-1 (Berlin Time)- In the interval the- 

 comet will pass from Taurus, through ."Xries, graze the 



