412 



NATURE 



[January 24, 19 18 



Common is a remarkable spot for the botanist, and is 

 still fortunately an untouched and unspoilt piece of 

 country. For this and other interesting places care- 

 ful lists of the more uncommon plants are given. 



Capt. T. S. Masterson read a paper on "The 

 Petroleum Industry of Rumania" before the meeting 

 of the Institution of Petroleum Technologists on 

 January 15, in which he presented a very useful 

 summary of the position of this industry up to the 

 time of the entry of Rumania into the European war. 

 He gives a brief account of the geography and geology 

 of the Rumanian oilfields, and discusses at some length 

 the methods of exploitation employed. He shows why 

 t'he American method of drilling has proved a com- 

 parative failure, whilst the Canadian method has 

 proved very successful, and is preferred by most Ruma- 

 nian operators. The percussive water-flush method 

 has not fared much better than the American 

 method, but, on the other hand, the modern rotary 

 system has been highly successful in the loose sandy 

 marls met with in certain areas. The author con- 

 cludes that no one system can be advocated for general 

 use in Rumania, but that in each case the system 

 best adapted to the conditions must be selected, wher- 

 ever these conditions are known; in unexplored fields 

 he recommends the use of the percussion system. He 

 states that Rumania possessed sixty-one refineries with 

 a total capacity of 4^ million tons, whereas the 

 highest output of crude oil obtained in any year was 

 only 1-9 millions. He further directs attention to the 

 fact that practically the whole of the plant for these 

 refineries was supplied from Germany, together with 

 most of the raw materials employed in the construc- 

 tion of drilling rigs. In November, 19 16, when the 

 retreat of the Rumanian Army became inevitable, the 

 wells and refineries were destroyed as completely as 

 possible, and the paper concludes with an expression 

 of tJie hop>e that when the times comes for reconstruc- 

 tion Gre^t Britain will take steps to see that she shall 

 be in the position to furnish the requisite materials. 



A NEW type of difYerential dilatometer for thermal 

 investigations on steels is described in the September- 

 October Revue de M^tallurgie. The author, M. Pierre 

 Ghevenard, claims that the instrument is well adapted 

 for use in a steel works laboratory on account of trust- 

 worthiness and simplicity of design. Only small quan- 

 tities of metal are necessary ; the instrument is easy 

 to set up, and the readings are unaffected by vibrations. 

 An instrument of the type he describes has been used 

 for some time for routine tests in a large steel works 

 in France. It provides a useful complement to the 

 chemical and micrographic examination of certain 

 steels and their constituents, such as cementite, etc. 

 Finally, it has proved of value in the qualitative exam- 

 ination of slight modifications in the dilatability of 

 metals due to thermal or mechanical influences. The 

 author remarks, in conclusion, that the examination of 

 these and certain other phenomena rightly comes within 

 the scope of precise metrology. 



The following volumes are announced for early ap- 

 pearance in the "Collection Horizon" of Messrs. Mas- 

 son et Cie., Paris : — " Les premieres heures du Blesse [ 

 de Guerre," P. Bertein and A. Nimier; " L'Evolution I 

 de la Plaie de Guerre," Prof. A. Policard ; " Commo- { 

 tions et Emotions de Guerre," Prof. A. L^ri and Th. 

 Beck; "Traitement des Psychon^vroses de Guerre," 

 G. Roussy, J. Boisseau, and M. d'CElsnitz; " Blessures 

 du Crane," T. de Martel (revised edition) ; " Blessures 

 du Cerveau," C. Chatelin (revised edition) ; " Prothese 

 fonctionnelle en Chirurgie de Guerre," Ducroquet ; and 

 " Blessures de la Moelle et de la Queue de Cheval," 

 Prof. G. Roussy and J. Lhermitte. 



NO. 2517, VOL. lOOj 



OUR ASTRONOMICAL COLUMN. 

 Encke's Comet. — ^The following continuation of the 

 ephemeris of Encke's comet is from Mr Viljev's- 

 elements, and is for Greenwich midnight : — 



The magnitude was 15-0 on December 30, but may be 

 expected to reach at least 90 by the end of February. 

 In 1852, when perihelion was at about the same time 

 of the year, the comet was visible in bright twilight in 

 February, but it has probably declined in physical 

 brightness since that date. 



Solar Observations at Madrid. — In addition to the 

 usual convenient astronomical and meteorological 

 tables, the "Anuario" of the Madrid Observatory for 

 19 18 includes the detailed results derived from direct 

 photographs of the sun, observations of solar promin- 

 ences, and spectroheliograms of the sun's disc taken in 

 calcium light. The sun-spot record is for 19 16, and 

 gives the heliographic latitude and longitude of each 

 spot, together with its duration, area, and classification. 

 The prominence catak>gue is also for 1916, and includes 

 position, extent of base, height, and brightness of each 

 prominence observed. A similar catalogue of calcium 

 flocculi covers the period from October i, 1916, to 

 September 30, 1917. In addition, there are valuable 

 discussions of the distribution of each group of pheno- 

 mena in regard to time and position on the sun. In 

 the case of calcium flocculi, the discussion covers the 

 whole period of observation at Madrid, and is of par- 

 ticular interest because so few data have hitherto been 

 published. The unit of time adopted is that of the 

 sun's rotation, and the following mean daily numbers 

 of fliocculi for approximate years have been calculated 

 fiom the table given : — 



Period Rotations P''^^ f Mean daily 



observation number 



1912, Apr. 4-1912, Dec. 5 1-9 131 1-247 



1912, Dec. 5-1914, Jan. 18 10-24 169 0-704 



1914, Jan. 18-1914, Dec. 12 25-36 128 1-499 



1914, Dec. i2-i9i5,Nov. 4 37-48 134 4782 



1915, Nov. 4-1916, Dec. 17 49-63 149 7-506 



Spectra of Jupiter and Saturn.— A photographic in- 

 vestigation of the spectra of the planets Jupiter and 

 Saturn has been made at Glasgow by Dr. L. Becker 

 (Monthly Notices R.A;S., Ixxviii., 77). The spectra 

 extended from B in the red to K in the extreme violet, 

 and were about 11 cm. in length. Apparent absorption 

 bands introduced by the dyes used to sensitise the plates 

 were eliminated by the superposition of a positive 

 photograph of the lunar spectrum. The only absorption 

 band discernible in the spectra of the two planets is 

 the well-known band in the red, which Dr. Becker 

 finds to extend from A 6174 to A 6214. The supposition 

 that water vapour is present in the atmospheres of 

 these planets is not supported by the photographs in 

 question, as the water- vapour lines near D do no 

 differ in appearance in the spectra of the moon an 

 planets. 



