July i, 1909] 



NA TURE 



19 



basalts of County Anlrini, and consists of basic lava flows 

 covering Mcsozoic beds, and at Scawt Hill occurs the 

 " neck " of one of the volcanoes from which the lavas 

 came. A few years ago one of the members of the 

 section came unexpectedly on a basic dyke traversing the 

 dolerite neck. The neck has been found to be a fine- 

 grained ophitic dolerite. The dyke is a granitoid basic 

 rock, and may be classed as a diabase without olivine. 

 A section' of the chalk taken two yards from the dyke 

 showed it to be converted into a typical crystalline lime- 

 stone with large crystals of calcite. The geologists of 

 the Belfast Naturalists' Field Club made during the 

 excursion the observation that even at a distance from 

 the dyke the band of chalk in contact with the dolerite 

 neck seemed to have undergone a similar change, and to 

 have been converted into hornstone. 



In the U.S. Monthly Weather Reviciu of January last 

 references are made to interesting communications by Mr. 

 R. F. .Stupart, director of the Canadian Meteorological 

 Service (dated March, 1909), relating (i) to the establish- 

 ment of new stations in Newfoundland and Labrador, and 

 the proposed extension of storm warnings and weather fore- 

 casts to Newfoundland, and (2) to the supply of a complete 

 equipment to several stations in the north of Canada, 

 extending as far as Fort Macpherson (lat. 67° 27', long. 

 134° 57' W.). In connection with the source of " cold 

 waves " frequently experienced in North America, Mr. 

 Stupart thinks that the study of the far north with trust- 

 worthy barometer readings will be most valuable. He 

 remarks that the persistent high pressures found there in 

 some seasons apparently owe their origin to upper currents 

 from the equator coming to earth farther north than usual, 

 and that " we may very probably in the future connect the 

 situation in the equatorial regions and trade-wind belts 

 with that in the high latitudes." 



The first complete account of the new method which 

 hjs been adopted by the Gesellschaft fiir drahtlose Tele- 

 graphie to secure an almost undamped series of oscilla- 

 tions in the secondary circuit of the sender is given by 

 Prof. Fleming in the Electrician for June 11. The 

 primary spark is divided into eleven very short sparks of 

 about o-oi inch in length, which are formed between twelve 

 discs of copper, which may be water-cooled. The damping 

 is so great that not more than two or three oscillations 

 occur in the primary circuit, and the oscillations in the 

 secondary are therefore free oscillations, which are only 

 slightly damped. The device evidently marks a distinct 

 advance in wireless telegraphy. 



L.AST year in the Complcs rcndiis and in Lc Radium 

 M. J. Bccquerel described experiments on the electric dis- 

 charge through vacuum tubes which appeared to indicate 

 that, in addition to the canal rays, there existed positive 

 rays which could be deviated by a magnetic field by 

 amounts comparable with those to be expected if the rays 

 were composed of free positive electrons. In the Journal 

 de Physique for June, M. A. Dufour describes his own 

 work on the same subject. He has repeated and extended 

 M. Becquerel's experiments, and comes to the conclusion 

 that the observations do not warrant the statement that 

 the deviable rays observed are due to free positive 

 electrons. 



Mr. R. H. Collingiiam contributes an article in 

 Engineering for June 18 dealing with Ilgner-operated 

 winding-engines. The principle of the Ilgner system is 

 the employment of a motor-generator set coupled 

 mechanically to a heavy fly-wheel and electrically to the 

 motor driving the mill or winding gear. The motor of 

 the motor-generator is driven off the power mains, and 

 NO. 2070, VOL. Si] 



the function of the fiy-wheel is to minimise the variation 

 in the load drawn from the source of supply. All the 

 heavy loads which come on the mill are met from the 

 store of energy in the fiy-wheel. In order to obtain this 

 result, an automatic slip-regulating device is provided 

 in the rotor circuit of the induction motor driving the 

 motor-generalor set, which regulates the amount of slip 

 on the induction motor according to the amperes taken 

 by the stator, the slip-regulating device only coming into 

 operation when the stator current has reached a certain 

 fixed value. When this value has been attained the 

 regulating device increases the slip of the induction motor, 

 causing the speed of the set to drop ; the fly-wheel then 

 gives up energy corresponding to the given variation in 

 velocity. By this means the load on tlie supply mains is 

 kept much more steady than would be the case if no fly- 

 wheel were employed. Mr. Collingham treats especially 

 the mechanics of the problems involved with the view of 

 finding expeditiously the weight of wheel, size of motor, 

 &c., required in given cases. 



In our article upon the Astrographic Congress at Paris 

 (June 10, p. 440) it was stated that Rome was represented 

 by Signor Lias. We are asked by Dr. P. Emanuelli to 

 state that this should have been Signor Lais, who is vice- 

 director of the Vatican Observatory, and was the repre- 

 sentative, not of Rome, but of the Vatican. 



We have received from Messrs. Flatters and Garnett, 

 Ltd., of Manchester, a copy of their conveniently arranged 

 catalogue of collecting apparatus, nature-study appliances, 

 cabinets, museum glassware, glass-top boxes, pocket lenses, 

 and so on. The list is well illustrated, and reference to 

 its contents is made easily. 



Mr. John Murray has published a second edition of 

 Mr. R. H. Lock's " Recent Progress in the Study of 

 Variation, Heredity, and Evolution." The first issue of 

 the book was reviewed at length in Nature of April 18, 

 1907 (vol. Ixxv., p. 578), but it may be pointed out that 

 several alterations and additions have been made in the 

 present edition. A short list of references has been added 

 at the end of each chapter; the different chapters have 

 been revised and supplemented, and a new chapter has 

 been added. 



" A Short History of English Agriculture," by Mr. 

 W. H. R. Curtler, is announced by the Oxford University 

 Press for early publication. As the agriculture of the 

 Middle Ages has often been ably described, Mr. Curtler 

 devotes the greater part of his book to the agricultural 

 history of the subsequent period, especially the seventeenth, 

 eighteenth, and nineteenth centuries. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in July: — 

 July 3. I4h. 30m. Uranus in conjunction with the Moon 

 (Uranus 2° 22' N. ). 



7. lyh. Mercury at greatest elongation (21° 11' W.). 



8. 3h. 46m. Mars in conjunction with the Moon (Mars 



i" 21' N.). 

 II. I5h. Uranus at opposi ion to ihe Sun. 

 II. Mh. Saturn at quadrature to Ihe Sun. 

 iS. I7h. 5oni. Venus in conjunction with the Moon 



(Venus 3° 5' S.). 



19. i8h. Mars at greatest heliocentric latitude S. 



20. I7h. 39m. lupiter in conjunction with the Moor> 



(Jupiter 4' 22' S.). 

 2;. 5h. lyni. Mercury in conjunction with Neptune 



(Mercury 1° 6' N.). 

 25. I9h. Mercury in perihelion. 

 30. 22h. 4m. Uranus in conjunction with the Mosrk 



(Uianus 2° 16' N.). 



