Black Cow or Brown Cow (root beer float)

Entry in progress—B.P.
 
Wikipedia: Ice cream soda (variations)
Root beer float
Also known as a “brown cow” “black cow”, the root beer float is traditionally made with vanilla ice cream and root beer, but can also be made with other flavors.
 
In the United States and Canada, the chain A&W Restaurants are well known for their root beer floats. The definition of a brown cow varies by region. For instance in some localities, a “root beer float” has strictly vanilla ice cream; a float made with root beer and chocolate ice cream is a “chocolate cow” or a “brown cow.”
 
In 2008, the Dr Pepper Snapple Group introduced its Float beverage line. This includes A&W Root Beer and Sunkist flavors which attempt to simulate the taste of their respective ice cream float flavors in a creamy, bottled drink.
 
Google Books
Notes and Queries
By Oxford Journals (Oxford University Press), IngentaConnect (Online service)
Published by Oxford University Press, 1929
Item notes: v.157 1929
Pg. 68:
Another well-liked drink, known as ” black cow,” is made by pouring root beer over vanilla ice-cream.
 
18 August 1929, Salt Lake Tribune (Salt Lake City, UT), pg. 2C, col. 4:
Black Cow is a suggestion that will delight your guests. In each glass place a scoop of SUNFREZE Ice Cream and over it pour your cold Root Beer. Cookies may be served with this.
 
July 1931, Soda Fountain, “‘Pig Latin’ at the Fountain,” pg. 28, col. 1:
A language all its own has the Martin Fountain in Martin’s Confectionery at Puyallup, Wash., in the midst of the fruit and berry region of the Northwest, a slang which heightens the interest and the merriment of the fountain guest who places an order and listens with avid interest to hear the way that order is repeated.
   
For one “black cow”, one “old style”, “grind one”, a “strawn”, an “honest”, all mark the conversation of a simple fountain drink order into the technical language of this fountain which has established its own Pig Latin for the entertainment of its guests and employes.
   
In the old days, Western restaurants of log-cabin type, had similar slang. An order for a couple of eggs, sunny side up, was shouted to the kitchen: “Adam & Eve on a raft”. When the diner would change his mind quickly and decide to have them scrambled, then the burly waiter would quickly shout:  “Wreck ‘em.”
   
Now an interesting fountain of the West adds to tis service by the colloquialisms of the effervescing dispensers, bubbling over with good humor, and with joy in their work which makes them coin names and develop a vocabulary for the many specialties of the fountain.
   
Some of the more current appelations of this Northwest fountain are the following:
   
“An Old Style”—root beer.
“An Honest”—Cherry coke.
But perhaps the raison d’etre of “an honest” and how this name developed may be in order.  It simply relates to the honesty and truthfulness of one George Washington who cut down a cherry tree, and is used to name, therefore, a cherry coke.
“Shoot one”—a coco cola.
“Black cow”—a root beer with milk in it.
“Squeeze”—a lemonade.
“A canary”—a coco cola with lemon.
“Sour”—coco cola with lime.
“Grind one”—an orangeade.
“Strawn”—a strawberry soda.
     
Time magaine
Monday, Dec. 14, 1931
Black Cow
Sirs:
Shame on TIME for defaming the time-honored “black cow”! (TIME, Nov. 16).
Guzzlers know the “black cow” is composed of root beer and cream. . . .
WILLIAM L. VALLEE
New York City
 
4 August 1932, Appleton (WI)

, pg. 9, col. 1:
Black Cow
1 quart gingerale
1 quart vanilla ice cream
 
Place gingerale in tall glasses, add portions of ice cream. Mix with long-handled spoon. Serve at once. Root beer can be used in place of the gingerale, if desired.
     
Springtime Menus and Recipes
Pet Milk Co., St. Louis, MO
1935
Pg. 14:
Black Cow
INGREDIENTS: 
PET MILK, diluted with WATER, SUGAR, ROOT BEER extract, CINNAMON, NUTMEG, SUGAR.
 
July 1935, Soda Fountain, Clementine Paddleford column, pg. 32, col. 2:
AT LAST and quite by accident I have found the originator of “Brown Cow.” Someone is always writing to ask “how in the deuce do you make ‘Brown Cow.’” Well, I didn’t know and I thought I might never find out. Then I walked into (Pg. 33, col. 1—ed.) Tyler’s Drug Store in Pulaski, Virginia and there were Brown Cows all over the place. Mr. Tyler owned he had originated and named the mixture himself. Listen: Into a soda glass place 1 oz. of Chocolate Syrup, and 6 oz. of milk; add a little shaved ice, stir big with a spoon, top with whipped cream and sell for 5 cents.
     
15 October 1937, Kokomo (IN) Tribune, “‘Soda Jerking’ Delights Kiddies,” pg. 17, col. 2:
Root beer with a serving of ice cream will make the famous drink known as a “brown cow.” Ginger ale mixed with ice cream results in the well known Boston Cooler.
     
Google Books
Discovering American Dialects
By Roger W. Shuy, National Council of Teachers of English
Published by National Council of Teachers of English
1967
Pg. 21: 
A GLASS CONTAINING ICE CREAM AND ROOT BEER: a float, a root beer float, a black cow, a Boston cooler.