20 REPORT OF THE SECRETARY. 



exhibition building. On its reverse side an elaborate floral wreath com- 

 prising native products forms the embellishment. 



By the transfer to the Library of Congress of the greater portion of 

 the books belonging to the Smithsonian Institution, effected shortly 

 after the disastrous tire of 18G5, the former library room was rendered 

 available for other uses. This occupation for other more pressing re- 

 quirements and purposes, necessarily prevented its further emjDloyment 

 as a reading room. In view of the increasing number of emj)loyes con- 

 nected with either the Smithsonian Institution, the Kational Museum, 

 or the United States Fish Commission and Fishery Census Division, it 

 was thought proper to make some provision by which some of the more 

 interesting domestic and foreign periodicals received might be ren- 

 dered easily accessible to them. Accordingly the corridor of the east 

 range of the building has been fitted up as a reading room by the erec- 

 tion of reading desks on which are placed the successive numbers of 

 certain serials as they come to hand. These, of course, comprise but a 

 very small portion of the journals received by the Institutionj a fuU 

 list of which is given in the ai^pendix. 



RESEARCHES. 



An arrangement was made by the Institution a number of years ago for 

 the compilation of a series of tables of ascertained altitudes in the United 

 States, to be collected from data derived from State and county surveys, 

 and from miscellaneous surveys made in the construction of railroads, 

 wagon roads, &g.', the ultimate object being the preparation of a topo- 

 graphic relief model of the country. This work was put in charge of 

 Mr. Walter L. Nicholson, and a considerable amount of work was ac- 

 complished towards the end in view. Mr. Nicholson having, however, 

 been appointed topographer of the Post-Office Department, the con- 

 stant occupation of his time in the duties of his position interfered 

 with the prosecution of this work, so that he was unable to complete his 

 report, and for some years nothing further has been accomplished. The 

 United States Coast and Geodetic Survey having had committed to it 

 by act of Congress the charge of conducting a system of triangulations 

 to connect the Atlantic and Pacific coasts, has requested the use of this 

 material collected by the Institution with reference to elevations ; but 

 its transfer to that establishment has not yet been determined on. 



A subject which has of late years attracted considerable attention 

 from physiologists and others is the peculiar affection of vision known 

 as color-blindness.* This defect of chromatic sensibility exists in various 

 degrees, and to a much larger extent than is generally supposed ; and as 

 it does not appear to be usually accompanied with other optical imper- 

 fection of the eyes, many of its subjects are even unconscious of their 

 deficiency in this respect. Inasmuch as danger signals used at sea, upon 



* This abnormal condition of siglit is by many French writers characterized (not 

 very appropriately) as "Daltonism." 



