The CONTENTS. 
r 
III. A Difcourfe concerning the Difficulty of cu- 
ring Fluxes, writ occajionally on reading Dr. de 
Juffieu’f Memoire in the Hiftory , &c. of the 
(Royal Academy of Sciences in Paris, for the Tear 
1729. By William Cockburn, M. D. F. R. S. 
and of the College of Bkyficians, London; 
VI. A Letter from M\John Dove to Edmund 
Halley, LL. D. F. ^ S. and Reg. Ajlrom. at 
Greenwich, containing an Account of a Co- 
met feen on February 29, 1 7 5^- 
V. An Account of two Experiments of the Fricti- 
on of Pullies. By the Reverend J. T. De- 
faguliers, LL. D. F. R. S. 
I. An 
