CONTENTS. 
XI. On the Action of Nitre upon Gold and Platina. By 
Smithson Tennant, Esq. F. R. S. p. 219 
XII. Experiments to determine the Force of fired Gunpowder. 
By Benjamin Count of Rumford, F.R.S. M.R.I.A. p. 222 
XIII. A Third Catalogue of the comparative Brightness of the 
Stars ; with an introductory Account of an Index to Mr. 
Flamsteed’s Observations of the fixed Stars contained in 
the second Volume of the Historia Coelestis. To which are 
added , several useful Results derived from that Index. By 
William Herschel, LL.D. F.R.S. p. 293 
XIV. An Account of the Means employed to obtain an overflow- 
ing Well. In a Letter to the Right Honourable Sir Joseph 
Banks, Bart. K. B. P. R. S. from Mr. Benjamin Vulliamy. 
P- 325 
XV. Observations of the changeable Brightness of the Satellites 
of Jupiter, and of the Variation in their apparent Magnitudes; 
with a Determination of the Time of their rotatory Motions 
on their Axes. To which is added, a Measure of the Diameter 
of the Second Satellite, and an Estimate of the comparative 
Size of all the Four. By William Herschel, LL. D. F. R. S. 
P- 332 
XVI. Farther Experiments and Observations on the Affections 
and Properties of Light. By Henry Brougham, Jun. Esq. 
Communicated by Sir Charles Blagden, Knt. Sec. R, S. p. 352 
