I bought this wrench because of its Pierce Arrow logo stamp, its unusual configuration, and its low price.  The open end is 3 3/4 inches wide.  The closed hexagonal end is 1 1/2 inches across.  the wrench is just under 11 inches in length.

The wrench's steel is 1/8 inch thick, and the openings have 3/16 inch lips on the underside.  This wrench was designed to hold up, and not be distorted by use.

I would like to have some automotive expert opinions on the specific applications for this wrench.  Was the large end used on a Pierce truck's or automobile's exhaust manifold, or on one these vehicle's hub caps?  Did the smaller end tighten a gas cap nut, or something else?

I think hub cap , not sure about the smaller end . Spark plug?
https://www.google.com/search?q=pierce+arrow+hubcap&source=lnms&tbm=isch&sa=X&ei=8e3eUpHaJuy_sQTNjYG4Aw&ved=0CAcQ_AUoAQ&biw=1093&bih=514

My guess is large end for hub cap and other end for spindle nut.

For tightening the packing in the water pump shaft?
    Just another WAG but it is a common use for big, short wrenches.

about the same apparent size as the leftmost wrench in the toolkit in this photo: http://www.papawswrench.com/vboard/index.php?topic=198.0

The wrench came with Pierce Arrow Models 80 and 81 from 1924 thru 1928. The big end was for the hubcaps. Don't know about the small end.

Bus:

Thanks for the information on the OE end of this wrench.  The thought about the closed end of the wrench being used for a gas cap derives from Jay Leno's description of a White 909 M wrench which he gave me.  He said his 1909 White Steam car has a threaded gas cap that is opened by using the OE of the White 909 M wrench.  The White 909M wrench's OE is 2 inches wide vs. the 1 1/2 inch width of the Pierce Arrow wrench's closed end.  It seems to me that my first cars from the late 1940s also had fill 1 1/2 inch pipe diameters.  Were gasoline fill pipe diameters standardized some time between 1909 and 1928?