18 REPORT OF THE SECRETARY. 



mineralogical department, and the duplicates made up into sets for dis- 

 tribution to various educational establishments throughout the country, 

 or to be held for exchange for other minerals. Further reference to this 

 subject, however, will be found under the head of the National Museum. 



Among the investigations carried on by the Institution for the benefit 

 of the government may be mentioned the following : 



An examination of the character and cbemical composition of the 

 Appolinaris water, at the request of the Secretary of the Treasury, a 

 controversy having arisen between the custom-house authorities in New 

 York and the importers of Appolinaris water, as to whether the article 

 imported under that name really came unchanged from the springs or 

 was artificially charged with other substances, especially carbonic acid. 

 To solve this problem the services of several chemists were invoked, but 

 these furnished contradictory results, and the Smithsonian Institution 

 was therefore asked by the Treasury Department to give the subject 

 proper attention, specimens of the water being duly supplied. This was 

 among the most laborious researches ever intrusted to the Institution 

 for prosecution, requiring the constant labor of the chemist for several 

 weeks for its accomplishment. A report was finally made and trans- 

 mitted to the Secretary. 



Another investigation was as to the comparative percentages of carbon 

 in different brands of steel, made at the request of Chief Engineer Shock, 

 of the Bureau of Steam Engineering of the Navy Department. 



In addition to the chemical work actually performed in its laboratory 

 for the government, the Institution has also acted as adviser to the de- 

 partments in securing specialists for investigations too extensive for 

 the time and apparatus of its chemist, or which, for other reasons, could 

 not be undertaken by him. Among these may be mentioned an ex- 

 amination of crude opium, for the amount of morphine it contained, 

 made for the Treasury Department by Dr. Theodore G. Wormley, of 

 the University of Pennsylvania, and by Dr. W. M. Mew, U. S. A., of 

 Washington, &c. 



The attention of the inspector of marine products for the city <>t" 

 'Washington having been attracted by the occurrence of green oysters 

 among those offered for sale, the health department, under Dr. Smith 

 Townshend, requested of the Smithsonian Institution an investiga- 

 tion as to the cause of this color, the popular impression being that it 

 was due to the presence of copper in the water, and denoted a poisonous 

 condition of the oysters. Although this phenomenon is quite well known 

 in Europe, and green oysters are considered in Francean especial delicacy, 

 the examination desired was made by Dr. Endlich with very perfect tests 

 and without detecting any copper. In this connection it may be stated 

 that recent investigations in Europe have shown that the green color is 

 due to the presence of minute algae on which the oyster feeds voraciously. 

 In France the oysters are kept in pits along the seashore, where the 

 highly prized tinge is very soon acquired. 



By a resolution of Congress the Secretary of the Institution was ap- 



