[ 1082 ] 
but tanned in much lefs time, and with a fmaller quantity of bark, than in any other 
method hitherto known or pradtifed, p. 120 — 130. 
Leaves, the effedt of their effluvia upon air, p. 202, 203. 
Le Cerf, Mr. his account of the advantages of a newly-invented machine, much varied 
in its effects, and very uleful for determining the perfedi proportion between different 
moveables adting by levers and wheel and pinion, p. 950 — 998. 
Leeds , the proportionable number of inhabitants that die there annually, p. 154. 
Leibnitz , his opinion concerning the communicating of motion to bodies, p. 347. 
Leicefier , obfervations there on an eclipfe of the fun, June 24, 17 78, p. 1019. Dif- 
ference of the meridians of Paris and Leicefler, p. 1020. And of Greenwich and 
. Leicefter, p, 102 r. 
Levers. An account of the advantages of a newly-invented machine, much varied in its 
effects, and very ufeful for determining the perfect proportion between different move- 
ables adting by levers and wheel and pinion, p. 950 — 998. 
Ley. Tanner’s ley made from pigeon’s dung, p. 114. A more adtive ley may be pre- 
pared from kelp or pot-afh, p. 1 15. 
Leyden phial, method of firing gun powder with it, p. 305 — 307. New experiments upon 
it refpedting the termination of condudlors, p. 999. See Conductors. An account of 
Mr. Cavallo’s method of repairing broken Leyden-phials, fo as to make them again 
ufeful for experiments, p. 101 1, 10/2. A curious experiment with the Leyden bottle, 
P- 1 °S 3 — 1 ° 55 * 
Life, its powers capable of varying the heat in animals, p. 17, &c. Freezing parts of 
animals, with a view to fee if they would be reilored to the adtions of life when thawed, 
p. 3.4—38. 
Lightning. Sundry papers relative to an accident from lightning at Purfleet, p. 232. Mr. 
Boddington’s letter concerning it, ibid. Mr. Nickfon’s account of the accident, p, 233 
—233. The report of the committee appointed by the Royal Society for examining 
the effedt of lightning on the parapet-wall of the houfe of the Board of Ordnance at Pur- 
fleet, p. 236 — 238. Mr. Wilfon’s diffent from the above report, p. 239-— 242. A letter 
from the. Board of Ordnance to Sir John Pringle, enclofing an account of Mr. Benjamin 
Wdfon’s experiment?, addreffed to his Majefty, 242 — 244. Mr. Wilfon’s new experi- 
ments and obfervations on the nature and ufe of condudiors, made in confequence of 
the accident at Purfleet, p. 243. Defcripdon of a model of The Board-houfe at Purfleet, 
made for trying the experiments, p. 247 — 251. Defcription of the fubilitute for a cloud, 
p. 23 1-— 233. Of the machines ufed to charge the apparatus, p. 233, 254. The expe- 
riments, with obfervations thereon, p. 254 — 293. Experiments upon acceleration, and 
its efledts, with obfervations thereon, p. 290, Sec. Experiments on firing gun powder 
without the lead: appearance of a fpark, p. 302 — 304. Method of firing gun-powder 
with the Leyden phial, p. 305 — 307. Remark on the two methods, p. 307. Con- 
cerning 
