r vii i 



ADVERTISEMENT, 



TIIK Committee appointed by the Royal Society to direct the publication of the 

 Philosophical Transactions take this opportunity to acquaint the public that it fully 

 appears, as well from the Council-books and Journals of the Society as from repeated 

 declarations which have been made in several former Transactions, that the printing of 

 them was always, from time to time, the single act of the respective Secretaries till 

 the Forty- seventh Volume ; the Society, as a Body, never interesting themselves any 

 further in their publication than by occasionally recommending the revival of them to 

 some of their Secretaries, when, from the particular circumstances of their affairs, the 

 Transactions had happened for any length of time to be intermitted. And this seems 

 principally to have been done with a view to satisfy the public that their usual 

 meetings were then continued, for the improvement of knowledge and benefit of 

 mankind : the great ends of their first institution by the Royal Charters, and which 

 they have ever since steadily pursued. 



But the Society being of late years greatly enlarged, and their communications more 

 numerous, it was thought advisable that a Committee of their members should be 

 appointed to reconsider the papers read before them, and select out of them such as 

 they should judge most proper for publication in the future Transactions ; which was 

 accordingly done upon the 26th of March, 1752. And the grounds of their choice are, 

 and will continue to be, the importance and singularity of the subjects, or the 

 advantageous manner of treating them ; without pretending to answer for the 

 certainty of the facts, or propriety of the reasonings contained in the several papers 

 so published, which must still rest on the credit or judgment of their respective 

 authors. 



It is likewise necessary on this occasion to remark, that it is an established rule of 

 the Society, to which they will always adhere, never to give their opinion, as a Body, 



