222 EIGHTH ANNUAL REPORT OP 



the heavens with the predictions of the Smithsonian ephemeris. From 

 these comparisons it is found that the ephemeris gives the position of the 

 planet with a degree of precision not inferior to that w4th which the 

 places of the planets longest known are calculated. The labors, there- 

 tore, of Mr. Walker on the elements, and Professor Peirce on the 

 theory of the planet Neptune, have been crowned with complete suc- 

 cess. It is proposed hereafter to collect all the observations which 

 may have been made on the planet, and compare them v/ith the ephem- 

 eris, in order, if necessary, still further to correct the orbit 



Mcteoiology. 



The general system of meteorology now in operation in this country, 

 and described in the last Report, has during the past 3''ear been con- 

 tinued and gradually extended. The instruments constructed under 

 the direction of the Institution, wdth the aid of Professor Guvot, have 

 been further improved, and some slight changes, indicated by experi- 

 ence, have been made to render them more convenient to the practical 

 observer; and ihey may now be considered not only equal in accuracy 

 to the instruments of the best construction from abroad, but in some 

 respects superior. They are furnished with the means of rcad\^ adjust- 

 ment to the standard instruments; and beingin every instance accurately 

 compared before they are used, and the error corrected, the labor of 

 inserting a correction in the journal is avoided. New efforts have also 

 Ijeen made to obtain a still more accurate comparison between the 

 standard barometer of this countr\' and those of the more important 

 European observatories. For this purpose a second standard barometer 

 by Newman, compared with the standard of the Royal Society, and a 

 barometer by Ernst, compared with the standard of the Paris Observa- 

 tor}'', were ordered at the expense of the Institution. By a long series 

 of comparisons between these two instruments and others at Cambridge, 

 (Massachusetts,) Toronto, (Canada West,) atid Washington city, the 

 object sought has, it is believed, been obtained. The thermometers 

 also, constructed by Mr. Green, of New York, for the Institution, have 

 been compared with European standards ; and an important step has 

 thus been made towards obtaining reliable results as to the absolute 

 meteorological elements of the different parts of this continent. 



It was stated in the last Report that the regents of the University ot 

 New York had made an appropriation tor supplying thirty-three acade- 

 mies in that State wdth instruments, and had given the establishment 

 of the whole system in charge to this Institution. The State of Massa- 

 chusetts has also made a similar appropriation and arrangement. 

 During the past year the instruments for this State have been con- 

 structed, and a part of the stations established under the care oi 

 Professor Guyoi. 



At the last meeting of the American Association, a report was 

 made, and a series of resolutions adopted, for extending the system 

 of observations with the same instruments to other parts of this 

 continent. These resolutions directed the committee to memorialize 

 Congress for aid in extending the system under the direction of this 

 Institution ; to request the Secretary of the Treasury to provide for 



