CONTENTS. 
Royal Society, from Mr. William Dutton, Watch- 
maker in Fleet-llreet, p. 302. 
XXXIV. jin Account of Two Stones of remarkable 
Shapes and Sizes , which, for the Space of Six 
Tears , were firmly lodged in the Urethra of a young 
Man , and at length fuccefsfully cut out from thence. 
Addreffed to the Royal Society , on Thurfday, De- 
cember 13, 1779, at which Meeting the Stones 
themfehes , and a Drawing of the Stones , were pre~ 
J'ented to the Fellows of the Society , by Jofeph 
Warner, F. R. S. and Surgeon to Guy’s-Hol'pital, 
P- 3 ° 4 * 
XXXV. Experiments on the Tourmalin: by Mr. 
Benjamin Wilfon, F. R. S. In a Fetter to Dr. 
William Heberden, F.R.S. p. 308. 
XXX VI. New Experiments and Obfervations concern- 
ing Electricity ; by Robert Symmer, Eff F. R. S. 
Paper I. Of the EleBricity of the human Body , 
and the Animal Subjlances , Silk and Wool. p. 340. 
Paper II. Of the EleBricity of black and white 
Silk. p. 348. 
Paper III. Of EleBrical Cohefion. p. 359. 
Paper IV. Part I. Of Two dijlinB Powers in 
EleBricity. p. 371. 
Part II. Of Two difinB Powers in 
EleBricity . p. 3 So. 
A Letter to the Rev. Dr. Birch, Sec. R. S. concern - 
ing the Force of EleBrical Cohefion. p. 390.. 
XXXVII. Some Obfervations relating to the Lyncu- 
rium of the Ancients ; by William Watfon, M. D. 
F. R. S. p. 394. 
XXXVIII. An Attempt to account for the regular 
diurnal Variation of the horizontal magnetic Needle , 
and 
