ADVERTISEMENT. 



Lately publifhed, in one Volume, Bvo. Price Six-Shillings, in Boards, 



An ESSAY on ELECTRICITY; 



Explaining the Theory and Practice of that Ufeful Science ; and the Mode of 

 applying it to Medical Purpofes. — To which is added 



An ESSAY on MAGNETISM. 



The Third Edition, Corrected and Enlarged. 



By GEORGE ADAMS, 



Mathematical Inftrument Maker to His Majefty, and Optician to His 

 Royal Highnefs the Prince of Wales. 



Printed for, and Publifhed by the Author, No. 60, Fleet-Street, j 



Speedily will he publi/bed, by the fame Author > 

 ASTRONOMICAL and GEOGRAPHICAL ESSAYS: 



CONTAINING 



I. An Introduction to Aftronomy. 



II. On the Ufe of the Globes, in which the various ConftructionS at prefent 



made Ufe of, will be defcribed and explained. 



III. The Defcription and Ufe of the Armillary Sphere, Dr. Long's Sphere, the 



Orrery, the Tellurian and other Inftruments, defigned to facilitate the Study 



of Aftronomy and Geography. 



c 2 ' Preparing 



