The day breaks, but never falls. The night falls, but never breaks.
 
This observation has been cited in print at least as early as Harper’s Bazar (New York, NY) in 1889:
   
“It is a fact worth pondering that though the night falls around us it never breaks, whereas the day breaks, but never falls. We offer this delicate fancy to some struggling applicant for political honors.”
 
     
Chronicling America
12 November 1889, Morning Journal and Courier (New Haven, CT), pg. 1, col. 7:
It is a fact worth pondering that though the night falls around us it never breaks, whereas the day breaks, but never falls. We offer this delicate fancy to some struggling applicant for political honors.—Harper’s Bazar.
 
Google Books
22 February 1890, Nature (New York, NY), pg. 266,, col. 2:
It is a fact worth pondering that, though the night falls around us, it never breaks; whereas the day breaks but never falls.
 
9 July 1897, Hornellsville (NY) Weekly Tribune, “Local in Brief,” pg. 5, col. 1:
Queer, isn’t it, that night falls and never breaks, while the day breaks but never falls.
 
26 March 1899, Brooklyn (NY) Daily Eagle, “Passing Strange,” pg. 18, col. 6:
“How night falls yet never breaks, and how day breaks though never falls—.”
       
Google Books
21 February 1901, The Independent (New York, NY), pg. 464:
Night falls but doesn’t break. Day breaks but doesn’t fall.— Pennsylvania Punch Bowl.
 
Chronicling America
4 June 1915, The Evening Herald (Klamath Falls, OR), pg. 4, col. 2:
Day breaks and never falls, and night falls and never breaks.
 
Google Books
Scribner’s Magazine
Volume 79
1926
Pg. 325:
By the way, who was it that first called attention to the paradox that although night falls, it doesn’t break; and that although day breaks, it doesn’t fall?
 
27 May 1929, Riverside (CA) Daily Press, “Tower of Jewels,” pg. 14, col. 7:
Strange! Day breaks but never falls, while night falls but never breaks.
 
30 December 1931, New Orleans (LA) States, “The Passing Show” by W. P. Ball, pg. 4, col. 1:
A sign in front of a local welding machine shop announces, “we weld anything except a broken heart or the break of day,” reminded us of the old one, “Day breaks but never falls, while night falls but never breaks.”
     
5 March 1974, Springfield (MA) Union, “Fun Time—The Riddle Box” by A. Leokum, pg. 31, col. 4:
What falls but never breaks, and what breaks but never falls?
Night falls but never breaks and day breaks but never falls.
 
16 August 1976, Pittsburgh (PA) Post-Gazette, “Our Town” by Joe Browne, Daily Magazine, pg. 23, col. 5:
Mix Up
I don’t know if this occurred to 6-year-old Keith Lappman or whether he heard it somewhere. Anyway, he asks: “Why does night fall but never break while day breaks but never falls?” I don’t know why. It just happens.
 
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Why does night fall but never break and day break but never fall?
7:47 AM - 12 Jan 2009