Daniel walked as quietly as he could back into the laboratory. He set the tangents paper down on a table and then picked up an iron bar that was lying next to a furnace door for use as a poker. There was more than one way to get rid of rats; but sometimes the best approach was the simplest, viz. ambush and bludgeon. He stalked down an aisle between furnaces, wiggling the poker in his hand. The alcove had been partitioned from the rest of the room by a free-standing screen such as ladies were wont to dress behind, consisting of fabric (now shabby) pleated and hung on a light wooden frame. This was to stop flying sparks, and to shield Isaac's fragile scales and fine powders from gusts of wind coming through open windows or down chimneys.