No one painted water like Frits Thaulow. Just look at the river in this painting: it feels like it’s really moving, catching the light and swallowing it at the same time. He painted it in 1892 and called it Water Mill, a picture that does the hardest thing in all of art… it makes water look alive. What made him so extraordinary is that he could paint several kinds of water at once: the pale reflections of the buildings on the surface, the green tint of the water itself, the ripples running across the top, and the rocks sitting on the bottom, all of it layered together, melting into one another the way real water actually does. Most painters can manage one of those things. He gave you all four in a single glance. Thaulow was Norwegian, born in 1847, and he grew up in a country made of fjords, rivers and waterfalls, and he chose to spend his life on the single hardest subject a painter can attempt, the one thing that will not sit still and will not hold a shape. And in doing so, he made the fleeting beauty of water eternal...