Did you know that the invention of the collapsible metal paint tube in the 19th century, allowing artists to keep their oil paints both fresh and portable, made it possible for the Impressionists to pursue painting en plein air, or outdoors? Previously, paint had to be stored in pigs’ bladders, making its use much more cumbersome and unstable. Squeezing oil paint straight from the tube also encouraged the paint to be applied in thicker quantities, creating impasto effects characteristic of many Impressionist paintings. The introduction of brushes with a flat ferrule (the metal tube holding the bristles in place) enabled the paint to be applied more rapidly, allowing the artists to respond to fleeting atmospheric conditions. Newly patented folding easels also helped artists to become more mobile and not so tied to their studios. They were able to travel to the countryside by train, taking their portable painting kits with them. Monet, perhaps more than any of his fellow Impressionists, took full advantage of these substantial improvements. He was an inveterate traveller, who often sought new locations for inspiration.