“The stage for the narrator’s reflection on his present situation is set in the formless and colorless polar expanse to which his efforts have led him:
It is true that I have thought more, and that my daydreams are more extended and magnificent [than those of schoolboys of fifteen], but they want (as the painters call it) keeping; And I greatly need a friend who would have sense enough not to despise me as romantic, and affection enough for me to endeavour to regulate my mind.7
The narrator seeks cultivation, but fears that his thoughts and magnificent representations, his rich and perhaps even excessive poetic capacity, or in short, his romantic disposition, may be mistaken for mere disorder and enthusiasm. His disposition wants “keeping,” as he puts it, using a term from eighteenth-century aesthetic theory. Initially part of the vocabulary of painting, keeping designates “the maintenance of harmony of composition,” or more simply, “agreement, congruity,harmony.” Whether in reference to outline and form, or tone and color, ‘keeping’ concerns “the proper subserviency” or “proper relation” in “every part of a picture, so that the general effect is harmonious to the eye.”"
From The Literary Absolute: The Theory of Literature in German Romanticism
By: Philippe Lacoue-Labarthe; Jean-Luc Nancy et al.