The raised arm of a sundial that indicates the time of day by its shadow is the gnomon (NO-mon). A sundial has but one arm, what do you mean by secondary arm?
The secondary arm on a sundial is called the gnomon. It is the part of the sundial that casts a shadow to indicate the time of day.
a grass plot or sundial
They refer to the time - in hours. The slanted edge of the gnomon casts a shadow on the sundial at the position which represents the time.
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I have a sundial in the garden.The sundial were the earliest form of clocks.
That Yahweh (GOD) made time last longer
sundial
He used a portable sundial.
Primitive and crude mean the same thing. They're synonyms.
The answer depends on what is wrog with the sundial.
The pin of a sundial is called a gnomon. It is the part of the sundial that casts a shadow onto the dial face to indicate the time.