Original caption:

   MCCORMICK BUILDING, 112 State St.
   ESTATE OF C. H. McCORMICK.
                   Chicago, June 16, 1897.
   Luxfer Prism Company, The Rookery, Chicago.

Dear Sirs:

   In reply to your inquiry, I take pleasure in stating that your Prisms, placed in the pavement in front of Mr. Cyrus McCormick's building on State street, have effected a marvelous change. The basement, formerly so dark as to be of no value, excepting when lighted artificially, is now as bright as any first floor on the street. Fine print can be read at the rear, eighty feet back from the sidewalk.
   This daylight result has truly made an entirely different proposition of this portion of the building, and I estimate has added five hundred dollars a month to the renting value of the property.

Yours very truly,