The following Works have leen lately published ly 



the Author of these Lessons, 

 And may be had of J. CONDEK, 13, St. Paul's Church-yard. 



COURSE OF NATURAL AND MATHEMATICAL 

 PHILOSOPHY. 



Just published, to be had, either together or in separate 

 Parts, as follows : 



1. AN ELEMENTARY TREATISE ON NATURAL 

 PHILOSOPHY; Translated from the French of M. R. J, 

 Haiiy, with Notes, critical, illustrative, and historical, by 

 OLINTHUS GJIEGORY, L. L. D. of the Royal Military A ca-i 

 demy, Woolwich, in two Volumes octavo, with twenty-four 

 folding Plates, price I/. 4s. boards.' 



%* In this Work are treated the Subjects of Extension, 

 Impenetrability, Divisibility, Mobility, Velocity, Inertia, 

 Hardness, Elasticity, Ductility, Gravity, Accelerated Mo- 

 tion, Specific Gravity, Crystallization, Heat, Dilatations by 

 Heat, Thermometers, Combustion, Water in the States of 

 Liquidity, Ice, and Vapour, Capillary Attraction, Congela- 

 tion of Mercury, Steam-Engines, Air, Barometers, Syphons, 

 Pumps, Evaporation, Winds, Air Balloons, Theory of Mu- 

 sical Sounds, Electricity, Galvanism, Magnetism, Light 

 and Vision, with Descriptions of Electrical, Magnetical, 

 and Optical Instruments, &c. 



Testimonies in favour of this Treatise. 



" We have not yet seen a Treatise on Natural Philoso- 

 phy which approached so nearly to a systematic form; no 

 one completed with so much care, comprehending such a 

 variety of details, finished with more philosophical accu- 

 racy." Crit. Rev. Series 3. vol. i. App. 



" There is more originality of maneer and more vigour 

 of intellect discoverable in the Traite" de Physique of M. 

 Haiiy, than in any ether elementary treatise of Natural 

 Philosophy which has for many years made its appearance 

 in Britain. The Translator has executed his task with fide- 

 lity and skilh the public are well acquainted with his ta- 

 lents, and will doubtless feel much indebted to him for- 

 presenting so valuable a production to their notice : as well 

 as for having considerably increased its utility by the fre- 

 quent interspersion of copious notes." Eclec. Rev. vol. iv. 

 No. 2. 



- " Mr. Gregory has dene justice to theauthor in his trans- 

 lation, and has, we think, rendered a service to the public-' 

 by giving this treatise in an English dress. He has not, 



