"I'm sorry," said the clerk in flower shop, "we don't have potted geraniums. Could you use African violets instead?"
Replied the customer sadly, "No, it was geraniums my wife told me to water while she was gone."
Portland cementIn 1824, in Yorkshire, England, Joseph Aspdin, a stone mason, patented Portland cement, made by burning finely pulverized lime and clay at high temperatures in kilns (UK patent No. 5022). Thus Aspdin had made a manufactured counterpart to natural or Roman cement - a crude formulation of lime and volcanic ash used as early as 27 BC. Aspdin produced a hydraulic cement that would harden with the addition of water. He named his invention "Portland cement" not only to distinguish it from Roman cement, but also as a marketing tool: concrete made from his new cement resembled a highly prized building stone quarried on the Isle of Portland off the British coast. Like flour in a fruit cake, cement glues aggregate (sand or gravel) together to make a "rock" (concrete). |
