platinum-iridium

It's a cylinder of platinum-iridium about 39mm high, 39mm in diameter, cast by Johnson Matthey in Hatton Garden in 1879, delivered to the International Committee on Weights and Measures in Sevres shortly afterwards, polished and adjusted to be made equal in mass to the mass of the old French kilogram of the archives which dates from the time of the French Revolution.

Royal Society meets to weigh up the shrinking kilogram 2011

John Sinfelt (1931 -) is an American chemist noted for his invention of a superior platinum-iridium catalyst, an important advancement that allowed for the cheap production of lead-free, high-octane gasoline.

Sinfelt, John 2009

It's an espresso-shot-sized, platinum-iridium cylinder that is the perfect embodiment of the kilogram -- almost perfect.

The Ethical Hoax 2008

Engraving of the casting of the platinum-iridium alloy called the "1874 Alloy."

Meter 2007

The 1889 definition of the meter, based upon the artifact international prototype of platinum-iridium, was replaced by the CGPM in 1960 using a definition based upon a wavelength of krypton-86 radiation.

Meter 2007

I know there's a conservative Republican in Paris, made out of a platinum-iridium alloy, which serves as an international standard.

Althouse Derangement Syndrome. Ann Althouse 2007

She was looking through the glass partition at the computer and the platinum-iridium brain installed in the center of everything.

Time Was Perry, Steve 1998

In order to test the constancy of the battery, a red heat was maintained in a platinum-iridium wire by the current for six weeks, both day and night.

Scientific American Supplement, No. 363, December 16, 1882 Various

This anode simply consists of a square bit of platinum or platinum-iridium foil, measuring about 0.75 inch by 1 inch, and riveted on to a bent aluminium wire stem.

On Laboratory Arts Richard Threlfall

Samms did so, and there snapped around his wrist a platinum-iridium bracelet carrying, wrist-watch-wise, a lenticular something at which the Tellurian stared in stupefied amazement.

First Lensman Smith, E. E. 1950