[ 120 ] 8 



institutions. An aocor.nt of the first memoir was given in the last report. 

 It relates to the ancient monuments of the Mississippi valley, and occu- 

 pies an entire volume. It has been presented, as far as opportunity would 

 permit, to the principal literary and scientific societies of the worlds to all 

 the colleges and larger libraries of this country, and has everywhere been 

 received with much commendation. All the societies from which we 

 have as yet heard, have declared their v/illingness to co operate with the 

 institution, and to give us their publications in exchange, from which 

 source our lihrary has already been enriched with valuable additions. 



It is to be regretted that our means would not permit us to distribute 

 the first volume more liberally than we have done, and that the price put 

 upn the copies offered for sale has placed them beyond the reach of 

 many persons desirous of obtaining them. This arose from the fact that 

 in order to remunerate the authors for the exoense and labor bestowed on 

 the memoir, they were allowed to strike off from the types and plates of 

 the institution an edition to be sold for their own benefit. To avoid risk 

 of loss, the edition M-as a small one, and the price put at ten dollars. An 

 occurrence of this kind will not happen again; for, although it would be 

 desirable to pay authors for their contributions, yet it is now found that 

 materials will be offered, free of all cost, more than sufficient to exhaust 

 the portion of tiie income which can be devoted to publications'. 



In printing the future volumes it will be advisable to strike off an extra 

 number of copies for sale on account of the institution, and to dispose of 

 these for little more than the mere cost of press- work and paper. 



The second volume of Contributions is now in tiie press, and will con- 

 sist of a number of memoirs which have been submitted to competent 

 judges and found worthy of a place in the Sinithsonian publications. In 

 tliis volume we have adopted the {)lan of printing each memoir with a 

 separate title and paging. The object of this is to enable us to distribute 

 extra copies of each memoir separately, and also to furnish the author 

 with a number of copies regularly paged for his own use. It will also 

 enable us to classify the memoirs according to subjects. 



The following is a brief account of the memoirs contained in «he sec- 

 ond volume, so tar as they have been reported on by the commissioners 

 to whom they have been submitted: 



1. A Memoir on the planet Neptune, by Sears C. Walker. — An abstract 

 of this memoir has been published in the proceedings of the American 

 Philosophical Society, and has received the approbation of the scientific 

 world. It presents the several steps of the discovery of an orbit which 

 has enabled Mr. Walker to compute the place of the new planet with 

 as nmch precision as that of any of the planets which have been known 

 from the earliest times.* StarUng from the observations of the motion 

 of the planet during a period of about four months, Mr. Walker calcu- 

 lated an empirical orbit which enabled him to trace its path among the 

 stars of the celestial vault through its whole revolution of 1(36 years. He 

 was thus enabled to carry its position backward until it fell among a cluster 

 of stars accurately mapped by lialande towards the close of the last cen- 

 tury, and, after a minute and critical investigation, he was h^d to conclude 



* [t is proper to slate th;U a part of the researches given in this memoir was made during the 

 author's coMnexion with the National Ob^>'jrvatory, under the direction of Lieutenant JMaury, 

 An arxount of these will probably .soon be published in the n.xt volume of the records of opera- 

 UoJis of llus observaiory. 



