101
OF ENGINEERING FORMULAE.
Note5 on Lime—continued.
ROUGH TESTS OF HYDRAULIC LIMESTONES OB
cement (Pasley).
Colour bluish grey, brown, or some darkish colour.
Taste of clay when touched by the tongue.
Smell of clay after wetting.
1. Break into fragments about 1| inches thick, heat gradu-
ally in a common fire, and then keep to a full red heat for
about three hours. If it has been overburnt, it will be of a
darker colour than before when taken out of the fire. It pro-
perly calcined, no effervescence will take place when it is
placed in a glass of dilute hydrochloric acid.
2. Having obtained a piece properly calcined, pound it to
an impalpable powder, leaving no grit. Mix thoroughly under
a spatula or kitchen knife with about J of its bulk of water,
then knead into a ball, which should soon become warm.
3. When the ball has begun to cool, place it under water,
when it should not only continue hard, but go on hardening.
Its hydraulicity will be determined by the time it requires to
harden and the hardness it attains.
LIME BÜBNINQ. SECTION OF KILNS-
Fig I Will burn 240 cubic feet of lime per day.
Fig.2. 150,