SCIENTIFIC NEWS. ^C) 



He.lifis likewise contrived vessels for keeping oil, so that Vessel foi* 

 when the oil is drawn off, its place is supplied by water at ^y^J|!^o"t thick-t 

 the bottom. Thus, the vessel being always full, the oil is ening. 

 not thickened by the action of the air. 



A Course of Lectures on Natural Philosophy and the Mecha^ 

 nlcal Arts. By Thomas Young, j\/. D,, For, Sec. to the 

 n. S., F. L. S., late Prof, of Nat. Phil, in the Royal In- 

 stitution of Great Britain, S^c. 2 vols. 4to. 1570 pages, 58 

 plates. 



THIS valuable work has been for some time eagerly ex- Young"'s Natu- 

 pected ; but it has suffered no longer delay, than the co- 

 piousness of the subjects it -embraces, the great variety of 

 figures to be engraved, the large body of references, and the 

 accuracy required in every part of it, rendered indispensably 

 necessary. To give any adequate view of the multifarious 

 objects it embraces, would much exceed our limits ; we must 

 be content therefore with noticing them briefly. When Dr. 

 Y. undertook the office of professor of natural philosophy he 

 very properly conceived, that the plan of the Institution re- 

 quired something more, than a mere compilation from ele- 

 mentary works ; and therefore set himself to collect from 

 original authors, to examine with attention, and to digest 

 into one system every thing relating to the principles of the 

 mechanical sciences, that could tend to the improvement 

 of the arts subservient to the conveniences of life. In pur- 

 suing this course he has referred tlie fundamental doctrines 

 of motion to simply mathematical axioms, more immediately 

 than has been usual, and facilitated their application to 

 practical purpoies : very fully investigated the passive 

 strength of materials of all kinds, and formed many new 

 conclusions respecting it, of considerable importance to 

 the engineer and architect : simplified, extended, and il- 

 lustrated the theory and motions of waves, circulation of the 

 blood, and propagation of sound: investigated the curvature 

 of the images formed by lenses and mirrors : minutely exa- 

 mined the functions of the eye : copiously described and ac- 

 curately represented the phenomena of coloured light, and 

 pointed out some new cases of the production of colours : 



reduced 



