Washington, D.C., circa 1920. "Tabulating Machine Co." Our second look at the company's equipment. This installation is at the Old Post Office on Pennsylvania Avenue. Harris & Ewing Collection glass negative. View full size.

About 1961 in the camera store. The salesman is showing Dad the cutting edge of Polaroid Technology. The swipe marks are now visible across the bottom of the photo. Deanna Lowe is the beautiful subject ... previously afraid of cameras! View full size.

October 1910. "Wireless operator Ginsburg of Trent." Radioman Ginsburg aboard the steamship Trent, which, after being alerted by "Morse lamp," took on passengers from Walter Wellman's hydrogen dirigible America near Bermuda in an exciting air-to-sea rescue that saved all those aboard the foundering airship, including a tabby cat. 5x7 glass negative, G.G. Bain Collection. View full size.

"C & P Tel. Co." Another look at the operations of the Chesapeake & Potomac Telephone Co. around Washington circa 1925. Plus an interesting glimpse at the kind of working-class houses not usually seen in the photo archives from this era. National Photo Company Collection glass negative. View full size.

June 6, 1950. Pembroke, Ontario. "Vis-O-Matic department store." A variation on mail-order shopping, the Vis-O-Matic system used color slides to display merchandise to potential customers, with orders placed by Teletype and delivered to your door. Photo by Bernard Hoffman, Life image archive. View full size.

1917. "Census Bureau, Department of Commerce, tabulating machine." An early punch-card tabulator, a distant forebear of today's computers. Two photos of this monster yet to come. Harris & Ewing Collection glass negative. View full size.

January 14, 1924. "Mrs. Harry S. New," wife of the Postmaster General. This might be good fodder for a caption contest. Which commences right now with yours truly as the judge. National Photo Company glass negative. View full size.