ity to the explosion

of,

in building, rules for the use of, 45
plates, resistance of to projec-

tiles,
wrought, durability of,

7, 81

33

interesting

ments with,
white,

Gunny bags, what are?

Gutta percha, substitute for,

66

"" use of, for artificial
hoofs for horses,

Hail and mist, production of,
Hair, changes of color in,
Hallucinations, causes of,
Heat, animal, origin of,

conduction of, by gases,
conversion into mechanical
force,

effects of long-continued,
equivalent of,

lunar,

96

210 Keroselene,

311

197

311 Kerosene oil, non-explosiveness of, 208

lightning, what is?

66

158

on,

213

sun's, possible age of,

150

Heather, a native of the United

66

States,

312

66

action of,

influence of the colored rays

313

Labor,

62

66

156

218

106, 107, 112, 113

144

150

143

104

103

Henry, Professor, on atmospheric
electricity,

Horn, malleable, manufacture of,
Horses, artificial hoofs for,

runaway, new check for,
Horticulture, iron as a tonic in,

Human race, future of,

66

66 inferior types of,

Hydraulic power,

Hydrogen, action of, on metallic so-
lutions,

Hyperides, curious discovery of an
oration of,

316 Lignites, origin and constitution