Yves Tanguy arrived at his lunar or submarine morphology in about 1927, and spent the rest of his artistic career exploring and elaborating it without changing its essential character. His compositions, arrived at in an unpremeditated manner directly on the canvas, recall the landscape of Locronan, in the French province of Brittany, where he spent childhood summers at a home owned by his parents. The repertory of memory was augmented by his experience of Africa during a trip of the early 1930s. After this, the light in his paintings became clear and strong and the color schemes more complex. Vegetal forms were replaced by mineral formations. Dolmens and menhirs, stone remnants of prehistoric ages, and fossilized bones were smoothed and tinted in the dream spaces of his canvases. The assertive shadows cast in these landscapes recall those of Giorgio de Chirico, whose example had inspired Tanguy to take up painting in 1923.

The spatial paradox of The Sun in Its Jewel Case depends on the merging of sky and earth, achieved through the continuous gradation of color over the surface—there is no horizon line—and the device of a diagonal line of forms shown receding in perspective from lower right to upper left. Acute angles are suggested throughout, by the placement of objects, by the relationship of shadows to objects, or by the things themselves. Geometric precision and a minutely detailed academic technique, in which careful modeling lends plastic solidity to form, heighten the poetic strangeness of Tanguy’s world.