Solitudine can be dated to 1910-1911, when Longoni, now free from economic difficulties thanks to the annuity granted to him in 1906 by the entrepreneur Pietro Curletti in exchange for a large part of his production until then, devoted himself to painting with an unprecedented arrangement of soul. Solitude, ethereal alpine landscape, articulated on three perspective planes that from the crystalline lake silhouetted in light lead the gaze towards the gloomy valley and the snow-capped peaks in the background, the painting is played on the shades of a cold blue warmed by a diffused point-like note of pink which is built on the basis of a complex divisionism. The consistency of the brushstroke is denser in the multicolored texture of the lawn and increasingly diaphanous elsewhere, where the sign widens and frees itself to accommodate the discontinuity of the slopes. Fulcrum of the scene, lost between the unreachable heights of the sky and the frightening abysses of the earth, a figure emerges on the left reflected in the clear waters, to establish an effective vertical counterpoint and inspire feelings of peace and extreme melancholy.