March 2, 19 16] 



NATURE 



n 



21 56-9 ... II-9 

 1915. — We have received 



OUR ASTRONOMICAL COLUMN. 



A New Comet. — The Astronomer Royal informs us 



,it he has received the following telegram from 

 Prof. O. Baeklund, director of the Pulkova Observa- 

 tory : — " New comet Neujmin.. i lomag., February 24, 

 9h.'i7m. Simeis M.T., R.A. 8h. 58m. 40s.. declination 

 16° 24' N. Motion slow. Probably south." A further 

 observation telephoned to us as we go to press is as 

 follows :— R.A. 8h. sSm. 29SS., declination -f 14° 42' 

 --^'. February 27. iih. 33-6m., G.M.T. 



Comet 1915a (Mellish). — Additional measures of the 

 condensations in the tail of this comet are given in 

 Lowell Obser\'atory Bulletin, No. 70. Photographs 

 taken with the 40-in. reflector have been measured by 

 Mr. C. O. Lampland. Mr. E. C. Slipher made visual 

 ^■crometric measures with the 24-in. refractor. 



The following positions of the comet are extracted 

 trom an ephemeris given in Circular 501 of the Astro- 

 tiomischen Nachrichten : — 



i2h. G.yLT. 



R.A Dec. Mag. 



h. m. s. 



March 2 ... 3 37 24 ... +20 56-6 ... 11-7 

 6 ... 40 12 



10 ... 43 9 



U.S. Naval Observ.\tory 

 a copy of the report of the superintendent of this 

 extremely active institution. The Gaithersburg Sta- 

 tion of the International Latitude Service has been 

 discontinued. Dr. F. E. Ross has been transferred 

 to Washington, together with the photographic zenith 

 tube for continuous determination of the variation of 

 latitude. 



A Daylight Meteor. — An extremely interesting 

 account of a great meteor seen over the Chusan 

 Archipelago during the forenoon of February 13, 

 1915, has been given by Capt. W. F. Tyler, R.N.R., 

 in a paper communicated to the North China Branch 

 of the Royal Asiatic Society (Journal, vol. xlvi.). 

 Capt Tyler's attention was directed to the matter by 

 the report of the light-keeper at Steep Island that 

 a man-of-war had fired an aerial torpedo which nearly 

 hit the tower. The combined observations from a 

 number of adjacent islands and from Shanghai seem 

 to be best fitted by assuming the meteor followed a 

 strongly curved path, at first travelling a little east of 

 north, and finally moving towards the south-east. The 

 meteor was seen to fall into the sea near Video Island, 

 and a violent explosion was heard over a ver\' wide 

 area. It is notable that exceptional meteoric displays 

 have been recorded about this date in previous years. 



.\ Transxeptu.nian Planet. — The first number of 

 ne first volume of the Memoirs of the Lowell Ob- 

 servatory deals with this alluring subject. Although 

 the cometary evidence which has been held to indicate 

 the existence of an additional member of the solar 

 system may be open to other interpretation, yet it 

 may be confidently predicted that extended knowledge 

 of the motions of the known outer planets will ulti- 

 mately settle the matter if, that is, the hypothetical 

 body, or bodies, exist. It is interesting to compare 

 the material Dr. Lowell finds available with that which 

 led to the capture of Neptune. In the first place, the 

 latter has not yet been known long enough to enable 

 its theory to be developed with the accuracy required 

 as a basis of a search for a source of perturbation, 

 hence instead of the planet next in the series, recourse 

 must be made to the antepenultimate Uranus. Then, 

 secondly, the residuals given by Gaillot's theory of 

 Uranus do not exceed 45" at any point of its path 

 (1709-1910), whilst in 1845 Uranus showed an unex- 

 plained discrepancy amounting to 133'. A comparison 

 of the present residuals, small though they be, with 



NO. 2418, VOL. 97] 



the probable errors of observations, shows that they 

 are too large to be due to the latter. By a lengthy 

 process of trial by error Dr. Lowell shows .that the 

 hypothesis of a single outside perturbing body can 

 reduce the residuals 71 per cent., or, including error* 

 of observation, by 90 to 100 per cent. Two solutions 

 are found to be equally indicated, one with the un- 

 known situated (July o, 1914) in heliocentric longitude 

 840°, for the other in 2628°. The distances, masses, 

 and eccentricities are closely alike, being about forty- 

 four times the earth's distance from the sun, 1/50,000 

 of the sun's mass, and an eccentricity about 0-2, indi- 

 cating a visibility of 12-13 magnitude, and a disc 

 slreater than i" in diameter. 



ARTIFKLAL IRRIGATION IN THE ' 

 WESTERN STATES OF NORTH AMERICA."^ 



THE hydro logical department of the United States 

 Geological Survey finds nowhere, perhaps, so 

 important and fruitful a field of operations as in the 

 great tract of countr}" which lies west of the looth 

 meridian of west longitude. The difficulties attending 

 the agricultural development of regions in which the 

 rainfall is so scanty as to be almost negligible are 

 sufficiently obvious, but the lack of adequate supplies 

 of water is no less felt for mining and industrial pur- 

 poses, to say nothing of ordinary domestic require- 

 ments. Hence arises the necessity for a close and 

 searching investigation into all such sources as are 

 actuallv available, and the conservation of supplies 

 from streams and wells, so that they may be utilised 

 to the best advantage, with the reduction of waste 

 and loss to a minimum. 



Such are the conditions prevailing on the south- 

 eastern portion of the State of Nevada. Large areas 

 of fertile soil lie idle for want of moisture to make 

 them productive, and very little vegetation survives, 

 unaided, the long periods of drought. The average 

 annual precipitation of rain at seven gauging stations 

 in different localities ranges from 342 to 11-99 in. 

 When a rainfall does occur, it often takes the form of 

 a cloudburst, in which a large quantity of water falls 

 on a small area in a very short space of time. Much 

 consequently is lost. The majority of the upland 

 streams, moreover, disappear in the alluvial slopes at 

 the foot of the mountains, and only flood w^aters from 

 heavy rains reach the central valleys. . Wells and 

 springs, therefore, constitute some of the most impor- 

 tant sources of supply, and they are found to give the 

 best vield in the unconsolidated sedimentary deposits 

 which partly fill the structural basins of the district. 

 The lower indurated strata,, forming what is called 

 the "bed-rock," are much less productive. These 

 lower formations are usually hard, compact, and im- 

 pervious laj'ers, representative of various systems, 

 mostly sedimentary, but with some igneous intrusions. 

 Thev serve the useful purpose of confining the water 

 which enters the "valley-fill," and of preventing its 

 downward escape. 



Tularosa Basin, in New Mexico, with an area of 

 6000 square mites, is another arid region with similar 

 climatic conditions. The sky is generallv clear, the 

 atmosphere dr\', and the average rainfall in the lower 



"Ground Water in South-Fistern Nevada." By Everttt Carpenter 

 (Water Supply Papr -)6?.) Pp. 86, wiih diaeratns and ^ nlates. 



"Geology and Water Rr>ource>! of Tularosa Basin, New Merico." By 

 O. E. Meinz»r and R. F. Hare (Water Supply Paper 343.) Pp. 316, with 

 diai^rams and 19 plates. 



" Spring"; of California." By Gerald A. Waring (Water Supply Paper 

 338.) Pp. 410, with diaeratns and 73 plates. 



" Ground Water for Irrigation in the Sacramento Valley. California." 

 By Kirk Bryan (Water Supply Paper 375 A.) Pp. 49, with diagrams and 

 2 plates. 



'■'Ground Water Res.->urces of the Viles Cone and Adjacent Areas,. 

 California." By W Q. Clark (Water Supply Paper 345 H.) Pp. 43, with 

 diaerams and q plates 



(Issued by United States Geological Survey, Washington, 1Q15.) 



