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ies in pitchblende, and various other uranium minerals. Symbol, Ra; atomic weight, 226.4. Radium was discovered by M. and Mme. Curie, of Paris, who in 1902 separated compounds of it by a tedious process from pitchblende. Its compounds color flames carmine and give a characteristic spectrum. It resembles barium chemical…

The olfactory organ of some Mollusca. It is connected with the organ of respiration.

Rays of relatively low penetrating power emitted by radium and other radioactive substances, and shown to consist of positively charged particles (perhaps particles of helium) having enormous velocities but small masses. They are slightly deflected by a strong magnetic or electric field.

readily deflected by a magnetic or electric field, emitted by radioactive substances, as radium. They consist of negatively charged particles or electrons, apparently the same in kind as those of the cathode rays, but having much higher velocities (about 35,000 to 180,000 miles per second).

ely related chemically to bismuth. It emits only alpha rays and is perhaps identical with radium F.

A small instrument containing a minute particle of a radium compound mounted in front of a fluorescent screen and viewed with magnifying lenses. The tiny flashes produced by the continual bombardment of the screen by the a rays are thus rendered visible. -- Spin*thar`i*scop"ic (#), a.