THE SMITHSONIAN INSTITUTION. 161 



been received with much commendation. All the societies from which 

 we have as yet heard, have declared their willingness to co-operate 

 with the Institution, and to give us their publications in exchange, from 

 which source our library has already been enriched with valuable ad- 

 ditions. 



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 upon 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 expense and labor be- 

 stowed 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 was 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 the income which can be de- 

 voted 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 dis- 

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



The second volume of Contributions is now in the 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 Smithsonian publications. In 

 this volume we have adopted the plan of printing each memoir with a 

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

 bute 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 likewise enable us to classify the memoirs according to subjects.. 



The following is a brief account of the memoirs contained in the 

 second volume, so far as they have been reported on by the commis- 

 sioners to whom they have been submitted : 



\. 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 much precision as that of any of the planets which have been known> 

 from the earliest times.* Starting 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 166 years.. 

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

 a cluster of stars accurately mapped by L aland e towards the close of 

 the last century ; and, after a minute and critical investigation, he was 

 led to conclude that one of the stars observed by Lalande on the night 



* It is proper to state that a part of the researches given in this memoir was made during. 

 the author's connection with the National Observatory, under the direction of Lieutenant 

 Maury. An account of these will probably soon be published in the next volume of the re- 

 cords of operations of this observatory. 

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