EEPOET OF THE SECRETAEY. 33 



instance, at those wliicli have been adopted by this Institution, viz: 7, 

 2, and 9; since, by observing this rule, corrections derived from such 

 observations as those made by Mr. Lewis can be applied so as to give with 

 more precision the average temperature of the place of observation. 

 The present Surgeon General, Dr. Hammond, takes a lively interest 

 in meteorology, as one of the branches of science intimately con- 

 nected with his department; and as soon as the posts and canton- 

 ments are again permanently established will reorganize the system 

 of army observations on a more extended scale, and furnish it. with 

 the instruments and instructions prepared under the direction of this 

 Institution. 



Lahoratory. — The operations of the laboratory during the past 

 year have principally consisted in the preparation of a large quantity of 

 Laborraque's disinfecting liquid, and the continuance of the examina- 

 tion of minerals preparatory to a distribution of duplicates. More than 

 a thousand bottles of the disinfecting liquid have been prepared for 

 the use of the hospitals in the city of Washington. The efBcacy of 

 this substance has been demonstrated by abundant experience. 

 Simply sprinkling it on the floor, or wetting with it a cloth placed 

 near the source of unpleasant effluvia, at once renders the air of 

 the apartment entirely inodorous. The preparation of this substance 

 is still going on and will be continued as long as the article may be 

 required for the hospitals. 



The examination of the minerals preparatory to a distribution of 

 the duplicates has not been carried on as rapidly as could be wished, 

 on account of the absence of the person to whom this duty was as- 

 signed. We have, however, ready for distribution, upwards of two 

 hundred sets of specimens, properly labelled, of the stones used in 

 erecting the public buildings in the city of Washington. 



In consideration of the high rate of exchange no purchases of 

 foreign apparatus have been made during the past year. Occasion 

 however, has been taken, in the interval of other business, to remodel 

 the cases of the apparatus room, in order to a better disposition and 

 display of the instruments. The room itself is fifty feet square with 

 a ceiling of twenty-five feet in height. Around the four sides of this 

 room, cases of about six feet deep and ten feet high have been con- 

 structed. The upper floorings of these cases extend about two feet 

 beyond their front, and thus form a projecting gallery entirely around 

 the room, which serves for the display of larger instruments as well 

 H. Mia. Doc. 25 3 



