Keeping it Cool with Slate: The Arctic Butter Box

A Cooling Rock System

On 2 August 1887, Mr. Adoniram J. Cushman of Monson, Maine received a patent for slate treatment. His invention “…relates to an improved composition bath for treating slate or other porous stone and has especial application in the preparation of the slate lining used in refrigerators, butter, berry, and fruit boxes…”. The “Arctic Butter Box” helped countless families in preserving their perishable food before electric refrigeration.

    
For centuries, food preservation presented a problem. Few areas in the world have a perfect year-round temperature for growing, so humans needed to devise ways to preserve food. Dehydration, pickling, canning, and salting all served the purpose to fight off rot. Refrigeration played a role as well. Before electric refrigeration, people “refrigerated” food in a variety of ways but the primary way was keeping ice or snow from melting. For example, some dug basements and lined them with hay, which helped insulate the area to keep the ice from melting. People learned that slate made a good liner for its ability to hold in the cold. However, slate is a porous stone and often absorbs the odors of anything enclosed with it. Hence slate-lined boxes got quite smelly. The invention Cushman created was a chemical mixture that helped seal the pores of the stone, keeping it from absorbing smells, and creating a scentless container for anything. The Monson Butter Box later debuted at the Sixteenth Triennial Exhibition in Massachusetts. It was described as “…excellent and convenient article for the purpose for which it is designed”.  For Monson, this represented another avenue for them to pursue their slate ventures. Already owning a slate mine in Maine, the company created several retail companies to sell a variety of slate products coming from their mills. For many people, devices such as these helped in preserving food through the winter or food that easily spoiled in the warmer months. It would not be until the Rural Electrification program of the 1930s that most people across the United States received electricity in their homes. Once electric refrigerators became affordable, items like the Arctic Butter were no longer needed.

Sources

Cushman, Adoniram J. Composition Bath for Treating Slate or Other Porous Stone. Patent No. 367.372, filed April 12, 1887.

Nummer, Brian A. "Historical Origins of Food Preservation". National Center for Home Food Preservation. May 2002.

Report of the Sixteenth Triennial Exhibition of the Massachusetts Charitable Mechanic Association. Magazine. Mills, Knight & Co., Printers: Boston, MA. 1888.