. The Becquerel rays and the properties of radium . sto whether a substance may be expected to can only be ascertained by trial. The most characteristic and interesting propertyof the cathode rays is that they are deflected by amagnet. The deflection is very conspicuous and easyto observe. It is only necessary to bring a commonhorse-shoe magnet near any one of the tubes, and theluminosity of the glass will be seen to move, showingthat the rays are now falling on a different spot towhat they did before. To study the effect in detail, it is desirable to havea form of tube (fig. 5)
. The Becquerel rays and the properties of radium . sto whether a substance may be expected to can only be ascertained by trial. The most characteristic and interesting propertyof the cathode rays is that they are deflected by amagnet. The deflection is very conspicuous and easyto observe. It is only necessary to bring a commonhorse-shoe magnet near any one of the tubes, and theluminosity of the glass will be seen to move, showingthat the rays are now falling on a different spot towhat they did before. To study the effect in detail, it is desirable to havea form of tube (fig. 5) specially designed for thepurpose. The cathode rays from a flat cathode haveto pass through two successive diaphragms. By thismeans the rays are confined to an exceedinglysharp and narrow beam. They then pass through ELECTEIC IN HIGH VACUA 5 a wide bulb, and produce a well-defined green fluor-escent patch on the end wall of the bulb. Theposition of this patch can be read by means of ascale fastened on to the outside of the tube. Before. Fio. 5.—Tube for obsenring and measuring the magnetic and electrostatic deRectionof tlie cathode rays. The beam of cathode rays from tlle fiat disc, a, represented by thedotted line, Is dediied by passage through the two slits in the metal discs, b b. Thesediscs are connected to the anode. The cathode rays form a well-defined fluorescentpatch on the wall at c. They can be defiected magnetically by means of flat coils of wirecarrying a current, which lie on either side of the tube, in planes parallel to the deflection is produced by the plates d <f, connected to the poles of abattery. entering the bulb, the rays have to pass between twoparallel metal plates, the object of which will beexplained later. In order to experiment upon the magnetic deflection,the bulb is placed between the poles of an electro-magnet, or, what is better, between two coils of wireof large radius, through which an electric current canbe
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectradioac, bookyear1904
