C iii 3 
ADVERTISEMENT. 
The 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 de- 
clarations 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 recom- 
mending 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 Transac- 
tions ; which was accordingly done upon the 26th of March, 
1 75%. And the grounds of their choice are, and will continue to 
