28 REPORT OP THE SECRETARY. 



observation, the amount of time consumed will be nearly 7,000 hours, 

 or, at the rate of seven hours per day, it will be 1,000 days or up- 

 wards of three years, or, in other words, to keep up with the reduction 

 of the current observations the whole available time of three expert 

 computers is required. This is independent of the labor expended in 

 the correspondence, preparation and distribution of blank forms, and 

 the deduction of general principles. The work has been prosecuted, 

 therefore, as rapidly as the means at the disposal of the Institution 

 would jjermit. Since the arrangement was made with the Patent 

 Office, from twelve to fifteen persons, many of them females, have 

 been almost constantly employed, under the direction of Prof. Coffin, 

 in bringing up the arrears and in reducing the current observations. 



All the materials collected at the Institution are in the process of 

 being arranged and bound in accessible volumes, with proper indices, 

 to be used by all who may be desirous of making special investigations 

 on any point relative to the climate of this country. 



During the past year the reductions for 1855 were printed in 

 pamphlet form and distributed to observers for criticism and sug- 

 gestions as to improvements which might be adopted in the subse- 

 quent publication of the entire series. 



Exchanges. — The system of international exchange has been carried 

 on during the past year with unabated zeal, and we trust with undi- 

 minished good results. A large amount of scientific material has 

 passed through our hands in its transfer to and from societies and 

 individuals in this and other countries. The returns made to the 

 Institution during 1857 for its own publications consist of 555 vol- 

 umes, 1,067 parts of volumes, and 138 charts. These works embrace 

 most of the current volumes of scientific transactions, and are of the 

 highest importance as aids in original research. The number would 

 be very much increased if the contents of several large cases, which 

 were accidentally delayed until the beginning of this year, were in- 

 cluded. 



The importance of the exchanges is not to be estimated by the com- 

 mercial value alone of the books received. In addition to this we 

 must consider the effect which it produces in bringing into immediate 

 communication the cultivators of literature and science in this country 

 with those abroad, of distributing among our societies publications of 

 a class, the existence of which would scarcely otherwise be known, 

 and of facilitating the diffusion of knowledge which, by the ordinary 

 modes of transmission, would not be attained, except, perhaps, in the 

 course of years. 



