The Montgomery advertiser., 1903-11-01
RADIUM AND
 RADIO ACTIVITY
PROF. McKAY's LECTURE ON RE-
 CENT DISCOVERIES.
Eject of Becquerel Rays-Possibili- ties of Practically Utiiizing the Energy of Radium-I.s Theo-
 retical Importance.
Brooklyn Eagle.

&tVh. JOuu o Achdy, Who iS Och'Sii"e . course of eight lectures at the Brooklyn Institute Museum on Eastern Parkway. on the subject, Recent Discoveries In Physical Science and Their Relations to Theories of Matter and Energy" yester- day discussed "Radium and Radio-Activ- fly; the Fight of Electrons." There was . large audience and Professor Mckay was warmly applauded. He said:
 A few months after Roentgen had as- tonished the world by his discovery of the wonderful X-rays, winch would pene- trate the flesh and give a shadow picture of the bones, Henri Becquerel announced that the metal uranium and all its com pounds. whether solid or in solution, emit invisible rays which are capable of pen strating bodies opaque to light. affecting . photographic plate through several thicknesses of black paper and ionizing the air 90 as to discharge an electro scope. In many ways the Becquerel rays seemed to resemble X-rays. only less in- tense in their action, requiring several days to make a shadow picture of the hand which the Roentgen rays would pro- duce in as many minutes. Later 1t was found that the Becquerel rays. or some of them, were defiected by a magnet and thus resemble cathode rays rather than x-rays, which are not influenced by magnet.
 Discoveries of M. and Mime. Curie.
 4 few years later M. and Mme. Curie of Paris began to experiment with pitch blend, the mineral from which uranium is obtained. endeavoring by the sensitive test of the eleotroscope to separate from the ore a purer form of uranium with greater radioactive power. From many tons of ore they succeeded by various chemical processes in securing sub stance with several thousand times the radiant power of uranium. From It's great activity and its atomic weight, which they found to be greater than that of uranium, they believed 1t to be new element and named 1t radium because ot its power to emit energy continuously and without apparent loss of weight. This prediction was later verified by Lord and Lady Higgins, who examined the spec trum of this wonderful substance and found 1t to contain lines differing from that of any known element. The Curies also discovered a radio active substance related to bismuth, which they named polonium in honor of the native country of Mime. Curie. But tkis substance has not yet been proved to be new element. It is believed to be only radioactive bis muth These brilliant discoveries have at tracted many other investigators to this interesting field of reesarch. who have QlScOVeTeQ OLner FdulO-dCliNe subStdhNSS and other properties of the rays until to- day the subject of radio-activity has be- come an important branch of physical chemistry and is destined greatly to ex- tend and modify, if not in some particu- lars to controvert our present theories or matter and energy
 Induced Eadio-Act1vity.
 A radio-s ctive substance may be defined as a substance that Is capable. at all temperatures. of spontaneously and con- tinuously emitting rays, i. e., rays capa- ble of penetrating bodies that are usually regarded as opaque. and producing cor |. tain characteristic photographic and elec- tric effects It Is found that large num- Der of bodies possess this power to a greater or less extent. Such rays have hetn detected as coming from many plants, the bricks and stones in our houses, freshly fallen snow and rain and the gases obtained from the water of deep wells But in most cases it Is only tenn porary activity and 1t Is not certain that 1t is not due to traces of radium In their conposition. or more probably it Is only an acquired or induced activity. due to the presence or contact of a permanently active substance, such as radium. thorium or uranium. For 1t is an established fact that these strongly active substances have the power of producing secondary but temporary activity in other bodies exposed for a time to their rays. A wood- CT or paper box In which radiurn is kept will emit rays for some days after the
 radium tubes have been removed. Profes-
 sor Curie is credited with the statement
 that he frequently finds 1t necessary to
 suspend his Investigations and remain
 away from his instruments for several
 hours on account of the secondary activ- lty acquired by his clothing and his body
 ln the presence of a powerful sample of radium So far as known there are only four or i've clements that are permanent ly radioactive. and in the case of one
 of two of these 1t Is not certain that it's power is not due to the presence of ra- lium. Radum Is a metal of the aka line earths belonging to the same group A as calcium stronitum and barium, and like them 1t is difficult to isolate and keep as an element Its radioactive property is studied not from the element but it's salts usually a chloride or bromide It manifests its power either in solid form nr in solution. For treatment of diseases the salt is hermeticaly sealed fin a small glass tube. Its radioactive power is es- timated in terms of pitchblerd CT uranium oxide. The samples exhibited have a EtrenEth of 1000, f. e.. 1000 times the "a dfo-active power of uranium oxide. It is me of the heaviest of the clements, its atomic weight being 25S. that of gold be- Ing 196. 'horium 232 and uranium 25S.
 Different Kinds of Becluerel Rays. closer study of the penetrating DOW sr. the luminescent and electric effects of the Becquerel rays has led to the conclusion that there are at least three kinds of rays all evoked simultaneously from the same element. although not nee sssarily in the same proportions in the