CONTENTS. 



Part II. 



Pacb 



N". XIII. On a Correction requisite to be applied to the Length of a Pen- 

 dulum consisting of a Ball suspended by a fine Wire : by 

 G. B. Airy, Esq. M.A 355 



XIV. On an Ancient Observation of a Winter Solstice: by R. W. 



RoTHMAN, Esq. M.A. 361 



XV. On the Crystals of Boracic Acid, S^c. : by W. H. Millek, Esq. 



M.A 365 



XVI. On certain Conditions under which a Perpetual Motion is pos- 



sible : 6?/ G. B. Airy, Esq. M.A 369 



XVII. Some Observations on the Habits and Character of the Natter- 



Jack of Pennant, with a List of Reptiles found in Cambridge- 

 shire: by the Rev. L. Jenyns, M.A. F.L.S 373 



Part III. 



XVIII. On the General Equations of the Motion of Fluids, both Incom- 

 pressible and Compressible ; and on the Pressure of Fluids 

 in Motion: by J. Challis, Esq. M.A 383 



XIX. On Crystals found in Slags: by W. H. Miller, Esq. M.A 417 



XX. 0)1 the Improvement of the Microscope : by the Rev. H. Coddikg- 



Tox, M.A. F.R.S 421 



XXI. On the General Properties of Defitiite Integrals: by R. Murphy, 



Esq. B.A 429 



