2 



Mr. Playfair's Dissertation was intended to furnish an 

 historical sketch of the principal discoveries and improve- 

 ments in Science, from the revival of Letters to the be- 

 ginning of the present century ; and, in that portion of it 

 which is prefixed to the Second Volume of this work, the 

 history is brought down to the period marked by the 

 commencement of Newton's discoveries. The remaining 



half was to have completed the design, in three parts or 

 > _ , 



subdivisions ; the First, comprehending the period of New- 

 ton and Leibnitz ; the Second, that of Euler and D'- 

 Alembert; and the Third, that of Lagrange and La- 

 place. 



Mr. Playfair was proceeding, with his accustomed di- 

 ligence and ardour, in the execution of this interesting 

 and congenial task, when he was seized with the illness 

 of which he died. The first subdivision of his plan, which 

 embraces a view of the advances made in the most re- 

 markable period of the history of Science, was happily 

 completed, and the printing finished, while he was yet 

 able to correct the Press. It is now given to the Pub- 

 lic, under the painful impression that it must too proba- 

 bly be considered as a Fragment ; for the editor fears, 

 that the materials collected for the completion of the 

 Dissertation, though containing the results of much ela- 

 borate inquiry, and profound reflection, cannot be put into 

 a shape that would justify their publication as a work of 

 Professor Playfair. 



Edinburgh, December 1819. 



