Incomplete question. Attached is the article under consideration.
Explanation:
1. in the lamplight:
this expression is used to create a mental picture of how the policemen's leather coats would have glistened when the lamplight was reflecting light rays on them.
2. from a pyramid of tins: the term "pyramid of tins" would have brought to mind a description of the size of the tins, just as how a natural pyramid looks magnificent.
