CONTENTS. 



I. The Croonian Lecture. On the Structure and Uses of the Mem- 

 brana Tympani of the Ear. By Everard Home, Esq. F. R. S. 



page 1 



II. On the Method of determining, from the real Probabilities 

 of Life, the Values of Contingent Reversions in which three 

 Lives are involved in the Survivorship. By William Morgan, 

 Esq. F. R. S. p. 22 



III. Abstract of a Register of the Barometer, Thermometer, and 

 Rain, at Lyndon, in Rutland, for the Tear 1798. By Thomas 

 Barker, Esq. p. 46 



IV. On the Power of penetrating into Space by Telescopes ; with 

 a comparative Determination of the Extent of that Power in 

 natural Vision, and in Telescopes of various Sizes and Con- 

 structions ; illustrated by select Observations. By William 

 Herschel, LL. D. F. R. S. p. 49 



V. A second Appendix to the improved Solution of a Problem in 

 physical Astronomy, inserted in the Philosophical Transactions 

 for the Tear 1798, containing some further Remarks, and 

 improved Formulas for computing the Coefficients A and B ; 

 by which the arithmetical Work is considerably shortened and 



facilitated. By the Rev. John Hellins, B. D. F. R. S. and 

 Vicar of Potter's Pury, in Northamptonshire. p. 86 



VI. Account of a Peculiarity in the Distribution of the Arteries 

 sent to the Limbs of slow-moving Animals ; together with some 



