N C E. 



CONTENTS. 



\. A N Account of the moving of a Bog, and the Forma- 

 tion of a Lake, in the County of Galwqy, Ireland. By 

 Ralph Ouflej, Efq-, M. R. I. A. - - Page 3 



II. An Account and Defer ipt ion of three Pendulums invented 

 and conflruEled by John Crojihwaite, JVatch and Clock 



Maker, Dublin _ _ _ _ _ (^ 



III. An Account of a new Method of illuminating the 

 Wires, and regulating the Poftion of the Traifit hiftru- 

 ment. By the Rev. Henry Ufsher, D. D. S. F. T. C. D. 

 M.R.l.A. and F.R.S. - . . 13 



IV. An EJfay to improve the Theory of defedlive Sight. 



By the Rev. John Stack, F. T. C. D. and M. R. I. A. - 27 



V. An Account offome Obfervations made with a view to 

 afcertaiti whether magnifying Power or Aperture contri- 

 butes moji to the difcerning fmall Stars in the Day. By 



the Rev. Henry Ufsher, D.D. M.R.l.A. and F.R.S. - 37 



VI. An Efay on the Variations of the Barometer. By 

 Richard Kirwan, Efq; M. R. I. A. and F. R. S. - 43 



VII. An Account offome Experiments on Wheel Carriages. 

 In a Letter from Richard Lovel Edgworth, Efq; 

 M.R.LA. and F.R.S. to the Rev. DoSlor Henry 



Ufsher, M.R.I. A. and F.R.S. - - 73 



VIII. An 



