[ §97 3 
Speculum « Directions for making the b.eft compofition fot the metals of reflecting tele- 
fcopes ; together with a defcription of the procefs for grinding, polifhing, and giving 
the great fpeculum the true parabolic carve, p. 296. See Telefcopes. 
Spheroid . How the joint centrifugal force of the particles of a fpherotd or cylinder,, 
having a rotatory motion about any momentary axis, is computed, p. 289—295. 
Spouts . Water-fpouts occalioned by eledlricity, p.141. 
St. Peter's church at Rome, its height determined by the barometer, p. 582. 
Stedman , Dr. John, on the degrees and quantities of wind requifite to move the heavier 
kinds of wind-machines, p. 493 — 503. 
Steel. A fieel-pendulum-rod dilates much more than one of folid-glafs, p. 698, 699. 
Stems of trees, the ufefulnefsof wafhing and rubbing them, to promote their annual in- 
creafe, p. 12. See Trees. 
Stewart, John, Efq. his account of the kingdom of Thibet, p. 465. See Thibet. 
Sting, none in drones, p. 25, 26. 
Strange , John, Efq. extradtof his letters ; with the Abbe Jofeph Toaldo’s letter to him, 
giving an account of the tides in the Adriatic, p. 144 — 161. 
Subjlance . An account of a hard fubflance extradted from a woman’s groin, p.461 — 
463. Caufed by a peg of wood which Ihe had fwallovved fixteen years before, 
p. 462, n. 
Sun, its adtion on the motion of the earth’s axis confidered in iome mathematical arti- 
cles, p/267 — 288. How the joint centrifugal force of the particles of a fpheroid or 
cylinder, having a rotatory motion about any momentary axis, is computed, 
p. 289—295. 
Swammerdam , on the propagation of bees. p. 16. 18. 
T a 
Tables* 
Obfervations pn the eledlricity of the atmofphere, p. 50. 
Experiments with Mr. Hemming’s eledtrical cylinder, u for feme days after ufing it, on 
the balls of Canton’s eledtrometer, p. 109— 1 13. 
Eledlricity of various fubftances difeovered by a fimple electrical apparatus, 
p. 122 — 126. 
Concerning the tides in the Adriatic, p. 15 1. 153. dEllus medius annorum, 1751 — 
175 c et 1760 — 1769. p. 155. JEitus medius ratione fitus Lunae, p. 158. Tabula 
asftus maris, fecundum xn. figna zodiaci, quatenus refertur ad Lunam, p. 160. 
Concerning the difference of longitude at Paris and Greenwich, refulting from the 
eclipfes of Jupiter’s firft fatellites, obferved during the laft ten years 5 with a com- 
parative table of the correfponding obfervations of the firft fatellite, made »in the 
principal obfervatories, p. 163. 165. 167. 170 — 186. 
A comparative view of the evaporation, rain, winds, and temperature of the air, dur- 
ing the year 1772, at Liverpool, p. 247. 
Vol. LX VII. 5T Com* 
