74 The American Geologist. Febiuaij, luos 
the king of Holland a member of a scientific commission to 
accompany a naval expedition to Java. The English block- 
ade prevented the sailing of the Dutch fieet, and the attempt 
was made by Dr. Troost to reach the United States and sail 
thence to the East Indies under our flag. He sailed from a 
German port in an American vessel bound for the United 
States, but was captujed by a French privateer and carried 
as a prisoner to Dunkirk, where he was confined until his 
true name and character were learned.. He was then re- 
leased, and proceeded to Paris. There he was elected a cor- 
responding member of the Museum of Natural History of 
France, his diploma being dated March 21, 1810. He had 
secured, however, on March 5, a passport in Paris permit- 
ting him to sail on an American ship from Rochelle to Phila- 
delphia, and shortly afterwards departed for America. 
On July I, 1810, Louis Napoleon abdicated the crown of 
Holland, and on July 10 that country was incorporated with 
the French empire. In the following year Java was sur- 
rendered to the British. 
Under these circumstances, Dr. Troost abandoned the 
expedition to the East Indies and resolved to remain in fhis 
country and become an American citizen. He settled in 
Philadelphia and soon established there a laboratory for 
manufacturing drugs and chemical preparations. 
In 1812, Dr. Troost became one of the founders of the 
Academy of Natural Sciences in Philadelphia and was elect- 
ed its first president, a position he held until 1817, when he 
resigned and was succeeded by Thomas Say. Soon after 
the founding of the Academy, when the members made dona- 
tions to form the nucleus of a museum. Dr. Troost presented 
some artificial crystals he had prepared. Later, he gave col- 
lections of minerals from Pennsylvania and from Marydand, 
and a number of other things of scientific interest and value. 
A collection of minerals purchased from Dr. Seybert came 
into the possession of the Academy on August 15, 1812, and 
soon- after this Dr. Troost delivered a course of lectures on 
mineralogy before fhe Academy. This was perhaps his first 
formal work as a lecturer or teacher. 
In 181 1, he became associated with others in the manu- 
facture of alum from the pyritic and lignitic Cretaceous clays 
