Sacchrometer, ii. 157

Saltpetre, ii. 81

Scapement, i. 86
Screw, i. 45

Sea salt, composition of, ii. 83
Selenium, ii. 125

Shock, electrical, i. 335
Silica, ii. 90

Silks, bleaching of, ii. 173
Silver, ii. 101
Silvering, ii, 275

Size, method of making, ii. 304
Soap, chemical composition of,
ii. 84. 128

Soda, ii. 82-manufacture of,
ii. 212
Sodium, ii. 83
Soldering, ii. 283

Solidity of matter, i. 2.
Sound i. 227
Spark, electric, i. 328
Speaking tubes, i. 230
Specific gravities, i. 117-table
of, i. 122
Spectacles, i. 257
Spermaceti, ii. 139.

Varnishing, ii. 239

Verdegris, ii. 110

Uranium, ii. 124

Boylean, i. 129

Valves, i. 202

Water, chemical constituents

of, ii. 54
Water-spouts, i. 175
Wax, ii. 132

Weather-glass, i. 150
Wedge, i. 44

Wheel and axis, i. 36

Zenith, i. 415
Zinc, ii. 114

Z.

Zirconia, ii. 93
Zodiac, i. 419