Moonlight over a Canal, Dordrecht
Monet said of Jongkind, "I owe the final education of my eye to him." No faint praise. Jongkind was an amazing artist, who expressed a constant softness in his art, which travelled from Romanticism into Impressionism, and enamored many Impressionists in the earliest days of that style to him for that softness. But there is also a considerable amount of tragedy in his works I can't quite put my finger on it, and if you know better how to explain it, please leave your version in the comments, but there is a constant melancholy, in the calm darkness and sunlight. This is not too surprising, though, as in his life, Jongkind was very unhappy and only briefly successful.
Perhaps the tragic quality is a calm too calm.
Skaters in Holland
Boatman by a Windmill at Sundown
The Interior of the Port at Rotterdam, Effect of Moonlight