Gerard Troost — Glenn. 73 
Between 1801 and 1807, Dr. Troost practiced as a phar- 
macist, both at Amsterdam and at the Hague, and served in 
the army first as a private soldier and later as an officer of 
health of the first class and during his service was wounded 
in the forehead and in the thigh. The work of a pharmacist, 
it should be remembered, was that of a chemist manufac- 
turing medicinal preparations and required a much fuller 
and more accurate knowledge of chemistry, botany and 
zoology than would be necessary for the mere compound- 
ing of prescriptions. 
He had by this time attracted the attention of Louis 
Napoleon, king of Holland, and was sent by him to Paris 
to continue his scientific studies. His passport bears date of 
July I, 1807. There he became a pupil and companion of 
Hauy, the celebrated crystallographer and mineralogist, and 
gained that knowledge of and fondness for mineralogy and 
crystallography which he always afterward manifested and 
which led his associates in America to wonder at his re- 
markable fidelity in remembering the exact angles of known 
crystals of minerals and his readily distinguishing rare and 
remarkable forms. While there he translated into Dutch 
Humboldt's "Aspects of Nature" and established thereby a 
lifelong friendship with the author. He soon became at 
home in Paris, familiar with its language and acquainted with 
its leaders of scientific thought. At some time between 
1807 and 1809, Troost traveled widely in France, Italv. Switz- 
erland and Germany under commission from the king of 
Holland collecting, by purchase, for him a large and valuable 
cabinet of minerals. It was most probably during his trav- 
els for this purpose in Germany that he sat under Werner's 
instruction and l^ecame his companion in excursions 
around Freiberg. Troost often referred in his lectures to 
incidents of his travels during this period and frequentlv 
spoke of Werner in warm terms of appreciation. Xo refer- 
ence was ever made by him to his having traveled in Egvpt 
and no authentication of the statement that he visited that 
country in a scientific capacity for the French government is 
obtainable. It seems highly improbable that such a trip was 
ever made. 
About the close of 1809 Dr. Troost was appointed bv 
