|
In my view, the Christian religion is the most important and one of the first things in which all children, under a free government ought to be instructed... No truth is more evident to my mind than that the Christian religion must be the basis of any government intended to secure the rights and privileges of a free people. Preface to 1828 Dictionary
|
IRID'IUM, n. [from iris.] A metal of a whitish color, not malleable, found in the ore of platinum, and in a native allow with osmium. Its specific gravity is above 18. It takes its name from the variety of colors which it exhibits while dissolving in muriatic acid. The native allow with osmium, or native iridium, is of a steel gray color and shining metallic luster. It usually occurs in small irregular flat grains, in alluvial soil, in S. America.
A rare metallic element, of the
same group as platinum, which it much resembles, being silver-white,
but harder, and brittle, and indifferent to most corrosive agents.
With the exception of osmium, it is the heaviest substance known, its
specific gravity being 22.4. Symbol Ir. Atomic weight
192.5.
* Iridium usually occurs as a native alloy with osmium (iridosmine or osmiridium), which may occur alone or with platinum. Iridium, as an alloy with platinum, is used in bushing the vents of heavy ordnance. It is also used for the points of gold pens, and in a finely powdered condition (iridium black), for painting porcelain black. | ||||||||