LEST WE FORGET.Some of the most heartbreaking — pictures made between 1861 and while battles raged between the North and the South. Pictured: A former slave reveals the scars on his back from whippings before he escaped to become a Union soldier.
Iceland spar is a clear, transparent, colorless crystallized variety of calcite (calcium carbonate, Large pieces are split along natural cleavage planes to form natural rhombs. Iceland spar is probably best known for exhibiting the optical propert
“Mad as a hatter” - In and century England, mercury was used in making felt for hats. Workers in hat factories were exposed daily to trace amounts of the metal, which eventually caused mercury poisoning in some, resulting in dementia.