A rare find!!  Sept 1912 Pin for the 8th International Congress of Applied Chemistry.  Bastian Bros.  Brass with white, red, and blue enamel.  1 3/8" X 1 1/4".  There is a 2nd "pin" closure on the back.  This would have held a ribbon or hanging metal bar with either the region or possibly the name of the pin recipient.  These pins would have been presented to the delegates upon arrival and registration. 
 
The first International Congress of Applied Chemistry was held in 1894 in Brussels, Belgium, and the eighth and last Congress was held in Washington and New York City in 1912. The ninth Congress was scheduled in St. Petersburg, Russia, in 1915 but was canceled because of World War 1 (1914-1918). After the war,  the Congress of Applied Chemistry was changed to the International Union of Pure & Applied Chemistry (IUPAC).
 
List of International Congress of Applied Chemistry events:
 
* 1st 1894 Brussels, Belgium.
* 2nd 1896 Paris, France (nearly 2,000 attended).
* 3rd 1898 Vienna, Austria.
* 4th 1900 Paris, France.
* 5th 1903, Berlin, Germany (2,533 attended, representing 38 countries).
* 6th 1906 Rome, Italy (2,375 attended).
* 7th 1909 London, England (4,100 attended).
* 8th 1912 Washington DC & New York City, United States (2,500 attended).