[ *° 7 2 ] 
Clay foil unfavourable to health, p. 218. 
Clocks* Glafs a ufeful fubftance far the pendulums of clocks, p. 446—452. 475, 476* 
Glcck-making. An account of a very ufeful machine for determining the perfeCt pro- 
portion between different moveables aCting by levers, and wheel, and pinion, 
P . 950—998. 
Clouds. They ferve as couduCtors of electric fluid, p. 229, n. Clouds in a very high 
ilorm frequently move eighty miles in an hour, p. 259. And about twenty miles 
with a moderate wind, ibid. Description of the fubilitutes for clouds in fome elec- 
trical experiments, p, 155, 156. And in experiments on the nature and ufe of con- 
ductors, p. 251 — 253. 
Cock, its comb and wattle frozen, with a view to fee if they would be reltored to the 
aCtions of life when thawed, p. 36. 
CocQa-nut. The fea cocoa-nut not a marine production, p. 178,179. Where it grows, * 
P* * 79 - 
Co/d, its effeCt on animals and vegetables, p. 7. S zz Animals > Vegetables . 
Cologne j town of, numberlefs bafaltic columns in and about it, p. 2. The walls of its - 
ancient buildings are of a tuffa refembling that of Naples, ibid. 
Colours . Mr. J. Scott’s account of a remarkable family-imperfeCtion of fight, with 
regard to colours, p. 612 — 614. Experiments to alcertain the order in which thd 
various colours fucceed each other on melted lead, p. 879 — 883. 
Comb and wattle of a cock frozen, with a view to fee if they would be reftored to the 
aCtions of life when thawed, p. 36. 
Committee . The report of the committee appointed by the Royal Society, for exa- • 
mining the effeCl of lightning on the parapet-wall of the houfe of the board of 
ordnance at Purfket, p. 236, 313 — 317. See Lightning . Reafons for diffenting . 
from the report of the committee appointed to confider of Mr. Wilfon’s experiments j 
including remarks on fome experiments exhibited by Mr. Nairne, p. 801 — 822. 
Compafs. An account of the advantages of a new-invented machine, much varied in 
its effects, and very ufeful for determining the perfeCt proportion between different 
moveables aCting by levers, and wheel, and pinion, p. 950 — 998. 
Compafs / Variation of the compafs obferved during a voyage from England to Davis’s 
Streights and Labradore in -177 6, p. 1057 — 1062. 
Gompongs , the villages of the“Caffia country in Sumatra, fo called, p. 165V 
Conductors. Points at their upper terminations more ufeful than balls to fecure houfes, 
&c. from lightning, p. 155 — 159. Rounded odnduCtors fecure buildings againit the 
cffeCts of lightning better than pointed ones, p, 245, &c. See Lightning . Pointed 
conductors recommended as the molt effectual for this purpofe, p, 314 — 317* 
Noife of the earthquake at Manchefter particularly loud in thofe houfes which were 
furniihed with conductors, p. 225. The efficacy of conductors with lharp and blunt 
terminations confidej'ed, 801— 822. Experiments on electricity^ being an attempt 
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