[ vi ] 



IX. On the Tides. By John William Lubbock, Esq. V.P. and Treas. R.S. . 143 



X. On the Nature of Death. By A. P. W. Philip, M.D. F.R.S. L. 8s E. S^c. . 167 



XI. An Account of a Concave Achromatic Glass Lens, as adapted to the JVired Mi- 



crometer when applied to a Telescope, which has the property of increasing the 

 magnifying poiver of the Telescope without increasing the diameter of the Mi- 

 crometer Wires. By George Dollond, F.R.S. ^c 199 



XII. On the Principle of Construction and general Application of the Negative Achro- 



matic Lens to T'elescopes and Eyepieces of every description. By Peter Barlow, 

 Esq. F.R.S. 8sc 205 



XIII. Some Suggestions relative to the best Method of employing the New Zenith 



Telescope lately erected at the Royal Observatory. By John Pond, Esq. A.R. 

 F.R.S. . .' ^. 209 



Appendix. 



Meteoi^ological Journal kept at the Apartments of the Royal Society, by order of the 



President and Council. 



