Mechanical and Refrigerating Engineer's Handy Book; Otto Luhr; 1913.
Automatic refrigerating liquid feeder and regulator; United States Patent 1725875; 8/27/1929.
Refrigerator car; United States Patent 1642882; 9/20/1927.
Since the title page states "Patent Applied For", this document was probably published around 1925.
Note the prices quoted for materials and labor:
Coal, $5.00 a ton. [In 2009, about $100/ton, down from $300 in 2008.]
Unskilled Labor, $6.00/day; that's DAY, not HOUR.
Skilled Labor, $8 to $10/day
Electricity, $0.009/KWH [my latest bill (in 2009) was $0.1317/KWH]
Note the job titles in the attached documents: Barnmen, Washers, Blacksmiths
Finally, the optimistic tone of the document contrasts with the decline of the ice business in the 1940's, fifteen years later. I remember the ice deliveries and the weight sign my mother put in the window before we got our first mechanical refrigerator after World War II.
[End Transcriber's Note]
DETROIT CREAMERY COMPANY