January 19, 1899] 



NA TURE 



that, in the opinion of this Association, it was both undesirable and 

 impracticalile to draw any line of separation between secondary 

 and technical education in any legislation concerning central 

 or local authorities, and another to the effect that in no case 

 should a permanent consultative committee be attached to the 

 Board of Education. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, December 15, 189S.— "The Action of 



Magnetised Electrodes upon Electrical Discharge Phenomena in 



Rarefied Gases." Preliminary Note. By C. E. S. Phillips. 



Communicated by Sir William Crookes, F. R.S. 



The experiments described in this paper were undertaken in 

 order to study, more especially, the action of magnetised elec- 

 trodes upon the phosptiorescent afterglow which is often seen to 

 illuminate the inner surface of the glass walls of vacuum tubes 

 when an electrical discharge has passed within them. 



The apparatus employed consisted of a glass bulb, nearly 

 spherical in shape and about 2j inches in diameter, open at both 

 ends, for the purpose of inserting and sealing into position, two 

 soft iron electrodes, so placed that their pointed ends were within 

 1/16 inch of one another. 



Each electrode had a screw-thread of suitable pitch cut upon 

 it in order that two brass cups, when screwed into position and 

 sealed with cement to the glass, might serve to keep the elec- 

 trodes central, to reduce the possibility of their rushing together 

 under the influence of strong magnetic forces, and to seal air- 

 tight the two ends of the bulb. 



Suitablearrangements having been made for strongly magnetising 

 the electrodes by means of a powerful external electro-magnet, 

 the bulb was then connected to a .Sprengel air-pump and slowly 

 exhausted. During this process the usual luminous phenomena 

 were observed whenever a discharge was passed through the bulb ; 

 while on magnetising the electrodes the results obtained were, in 

 some cases, very remarkable 



A rarefaction having been obtained such that a three-inch 

 spark from a ten-inch Apps induction coil could scarcely start the 

 glow, it was observed that, after a strong stimulation of the bulb 

 had taken place and then been stopped (the electrodes mean- 

 while remaining urmagnetised), on exciting the magnet a luminous 

 ring suddenly appeared within the bulb, between the pointed 

 ends of the electrodes, and in a plane at right angles to the 

 direction of the magnetic lines of force. It shone brightly for a 

 moment, when the magnet circuit was " made," and it was more 

 sharply defined at high exhaustions — becoming, in fact, hazy and 

 indefinite if the pressure within the bulb were slightly increased. 

 Even with the connecting wires between the coil and the bulb 

 completely removed after stimulation, the ring formed as well as 

 ever when the magnet was turned on. At the moment the ring 

 appeared within the bulb the glass w-alls became electrically 

 charged so strongly that, in some cases, a spark could be seen to 

 pass between the glass and either of the exposed ends of the 

 electrodes at the moment the magnet was excited. It was 

 further noticed that the ring was in rapid rotation and also 

 very sensitive to variations in the electrical charges, upon the 

 bulb. 



Under certain conditions a second ring formed concentrically 

 with the first. Experiments were also made with external 

 magnetic electrodes, and irregular green splashes and puffs of 

 white cloudy light appeared in the interior of the exhausted 

 vessel when the electrodes were magnetised. 



Geological Society, January 4.— W. Whitaker, F.R.S., 

 President, in the chair. — Capt. A. W. Stifife exhibited a fossil 

 Cardhiin (?) from the beach at the foot of the cliffs of Ormara 

 (Makran Coast). — "Geology of the Ashbourne and Buxton 

 Branch of the London and North-Western Railway : Ash- 

 bourne to Crake Low," by H. H. Arnold- Bemrose. The 

 southern ]iart of the new railway from Ashbourne, through Tis- 

 sington and Crake Low to Buxton, exhibits several sections in 

 Trias, Boulder Clay, Mountain Limestone, and Voredale Beds. 

 Interstratified with the latter is a thick bed of volcanic ash, with 

 thinner intercalations of tufif. Within a mile of Tissington ash 

 is exhibited four times in the cuttings, and according to the view 

 of the author it is the same bed repeated by basins and domes, 

 one of the latter of which is faulted. While the rocks succeed- 

 ing the ash in some places are limestones, cherts, and shales of 



NO. 1525, VOL. 59] 



Voredale type, in one section they resemble more closely the 

 upper beds of the Mountain Limestone. The limestones are 

 often dolomitised — "The Oceanic Depo.sits of Trinidad," by 

 Prof. J. B. Harrison and A. J- Jukes-Browne. The object of 

 this communication was to present some observations on the 

 succession and geological relations of the beds which have long 

 been known in Trinidad as the Naparima Marls. In his his- 

 torical introduction Mr. Jukes-Browne deals with the writings 

 of Mr. Guppy and Prof. Harrison, and shows that three definite 

 issues are thus raised : (i) Are the Nariva Beds above or below 

 the Naparima Marls? (2) Do the Globigcrina--mz.x\% occwx in the 

 Naparima district, and, if so, are they connected with the 

 Radiolarian marls, or are they part of a separate formation? 

 (3) What is the relation between the San Fernando Beds and 

 the other groups ? Mr. Guppy and Prof. Harrison agree in 

 answering the first part of the second question in the affirm- 

 ative, and in stating that the two marls are closely connected 

 together. It appears that the G!obigerina-mz.x\^ occupy the 

 place of the basal chalks of Barbados, but are much thicker, 

 while the radiolarian rocks are thinner, and the interbedded 

 volcanic ashes so frequent in Barbados are wanting in Trinidad. 

 Chemical and microscopic analysis of the Glohigeriim and 

 radiolarian beds are given, and, compared with similar analyses 

 of the Barbadian deposits, they show that more quart/, and 

 argillaceous matter occur in Trinidad. The following correlation 

 is proposed : — 



Barbados. Tri.nidad. 



Coral Rocks. 1 , i«„ ,„, «,,:„, f Pleistocene and 



Bissex Beds. } Moruga Series. 1 Pliocene. 



Oceanic Beds. 1 Naparima Mails. Miocene. 



o , J D J { Upper. I San Fernando Beds. ( Oligocene and 



Scotland Beds. | ^ower. , Nariva Series. t Eocene. 



The Oligocene and Eocene Beds are of shallow-water origin, 

 and seem to be unconformably covered by the Naparima Marls. 



P.4.RIS. 

 Academy of Sciences, January 9.— M. van Tieghem itv 

 the chair.— On the hysteresinieter constructed by MM. Blotidel 

 and Carpentier, by M. Marcel Deprez. The author describes 

 an instrument for the measurement of hysteresis, constrticted by 

 him about four years ago for the Conservatoire National des Arts 

 ct Metiers, the principle of which is identical with that of the 

 hysteresimeter recently invented by MM. Blondel and Carpentier. 

 the only differences being that the author's instrument was of 

 dimensions suitable for measuring the hysteresis of iron rings of 

 the size actually used in dynamos, and contained an electro- 

 magnet instead of a permanent magnet. — The cryoscopy of 

 urine, by M. Ch. Bouchard. From the observed depressicH> 

 of the freezing point of urine, suitably diluted if necessary, the 

 depression due to sodium chloride present is subtracted, and the 

 mean molecular weight of the rest of the solid matter determined 

 in the usual manner. In a man in a normal state of health the 

 value of this mean molecular weight is about 62, rarely falling 

 below 60, or rising above 68. In disease the value of this 

 constant is usually raised, varying from 68 to 112. — Histology 

 of the skin. Definition and nomenclature of the epidermal 

 layers in man and mammals, by M. L. Ranvier. Seven distinct 

 layers are described as existing in the epidermis of man and 

 mammals, each layer being characterised by perfectly clear 

 physical characters and chemical reactions. The names given 

 to these strata are : Germinativiim, filaincntosiiin, graniilosiint, 

 intcriiiedintn, Inciduui, corneitnt, anddisjiiiictiim. — Observations 

 of the total eclipse of the moon of December 27-28, made at 

 the Observatory of Bordeaux, made by MM. G. Rayet, E. 

 Doublet, and F. Courty, by M. G. Rayet.— Report on a memoir 

 of M. Partiot on the choice of a velocity formula.— Generalisation 

 of the analytical prolongation of a function, by M. Eugene 

 Fabry. — On the singular points of a function defined by a Taylor's 

 series, by M. Servant. — On the corres]3ondence between right lines 

 and spheres, by M. E. O. Lovett.— On the bending ofacylinder 

 with circular base, by M. Ribiere.— On the experiment of Lord 

 Kelvin and Joule, by M. A. Leduc— On the variations of 

 resistance of an electrolytic conductor in a magnetic field, 

 by M. II. Bagard. The author has succeeded in show- 

 ing that the resistance of a solution of copper sulph.ate, sud- 

 denly placed in a magnetic field of about 5000 C.G.S. 

 units, undergoes an increase of about one per cent, its 

 original value.— On the absolute value of the magnetic elements 

 on January I, 1899, by M. Th. Moureaux.— On the preparatioB 

 and properties of calcium arsenide, by M. P. Lebeau. This 



