Here's some Seasonal Affective Disorder from Making and Keeping Friends by William Menninger, 1952.

From the gloomy side to the sunny side, in the University of Michigan's 1910 yearbook.

Here's a review of our previously underground treatise on the profound secrets of Twilit Silence (publicly available for the first time in a decade):

Conley puts forth a method of noticing the subtlety of the space between day and night, especially when one can experience silence at that liminal time.  His thoughts on the matter, along with his collection of quotes and photographs on the subject, induced a bona-fide magical state of mind as I enjoyed them under the mid-day shade of a tree in a park in Berkeley.

—Clint Marsh (editor of Swami Panchadasi's Clairvoyance and Occult Powers: A Lost Classic), from his review in The Pamphleteer

Alive to those suggestions of a mysterious sphere of being that come to the man who of a night has watched the pearly grey of the weather-gleam.  From The Feeling for Nature in Scottish Poetry, Vol. 2, 1887.

"Rainy days bug you?  You are not alone."  From The Rotunda newspaper of Longwood College, 1965.

"There's a fine line in the shades of gray."

—Jeff Harris, The Forgotten Papers

From Reminiscences of School Life, and Hints on Teaching by Fanny Jackson Coppin, 1913.

There's a fine line 'Tween the Gloamin' and the Mirk (Cecile Macneill Thomson, 1882).

Light in the Gloaming, 1882.

From The Little Grammar by Ethan Allen Cross, 1922.

24 hours in 20 periods of night, twilight, and day.  From Diel and Seasonal Activities of Culicoides Spp. Near Yankeetown, Florida by Thomas Henry Lillie, 1985.

"Half light is good light," from an ad for Bauch & Lomb Plastigmat lenses, date uncertain.

"Then she prayed, 'Lead, Kindly Light, amid the encircling gloom," from Thrilling Life Stories for the Masses, 1892.