114 METEORS, ETC. 



in beds of quartz, sandstone, etc., and also in many rivers, 

 in minute and irregular grains. 



2. Platinum. — A white metal, extremely ductile and mal- 

 leable. It is the heaviest substance known, its specific 

 gravity being 21.5. It is not affected by air, moisture, or 

 any of the pure acids. It is found generally in small 

 grains, combined with palladium, rhodium, iridium, and 

 o.smium. 



3. Palla'dium. — A metal obtained in very small grains, of 

 a steel-gray color and fibrous structure, found associated 

 with platinum, or in auriferous sand. When native it is 

 alloyed with a little platinum and iridium. It is ductile and 

 very malleable, superior to wrought iron in hardness. 



4. Rho'dium. — A metal discovered among the grains of 

 crude platinum. It is of a whitish color, when pure is 

 brittle, and requires a much higher temperature for its 

 fusion than any other metal, unless perhaps iridium. It 

 readily alloys with every other metal but mercury, and is 

 insoluble in all acids. 



5. Ruthe'iiium. — A metal extracted from the ore of platinum. 

 It is of a gray color, very hard and brittle. 



6. Irid'ium. — A metal occurring only in the ore of platinum ; 

 it is the most refractory of all the metals, is brittle, and 

 has a white color. No acid will attack it, but it oxidizes 

 when ignited to redness in the air. 



7. Os'mium. — A rare metal, generally found in the ores of 

 platinum. It is, in the most compact shape in which it 

 has yet been obtained, of a bluish-white color, and, though 

 somewhat flexible in thin plates, is easily powdered. 



mp:teors and atmospheric phe- 

 nomena. 



Acon'tias. — A comet or meteor resembling the serpent. 



Aerolite. — A stone which has fallen from the air or atmos- 

 pheric regions. 



A'erolithol'ogy (Gr. aer, air, lit/tos, a stone, and logos, descrip- 

 tion). — The science of aerolites, or meteoric stones. 



Anthe'lion. — Luminous colored rings, or glories, observed 

 round the shadow of the spectator's own head, projected 

 on a surface covered with dew, or on a dense cloud or fog- 

 bank. 



