A review of early separable or detachable incandescent lamps was written by Dr. L.K. Böhm (Electrical World, Vol XX, No 23, Dec 3, 1892, pg 356). Pictures were in that article so that one can immediately tell if a lamp design can be considered a "stopper" lamp. Lamps of Grove, Konn, Sawyer-Man, Böhm, Maxim, Farmer, Böhm & Fox and Westinghouse were discussed. The Westinghouse Stopper Lamp was just about to be introduced to the public when the article appeared.

Lamps in addition to those mentioned above will now be considered. These were of considerable interest about 1893, just prior to the expiration of the basic Edison patent. Some of these patented lamps might not have made it to the marketplace.

Carl K. MacFadden and John Peil of Chicago patented the lamp shown below (see The Electrical Engineer, Vol XVII, No 307, Mar 21, 1894, pg 259).

The main feature of this lamp was that it utilized "the insulating properties of a thin coat of enamel on the inleading wires which are let into the glass receiver through a metal seal around the wires." The wires were wound in a spiral form before coating to increase the length. "One terminal of the filament is the metal plug or seal, thus doing away with one of the inleading wires and simplying the construction. After the seal is made by pouring melted alloy around the wire as it stands in place in the space to be filled by the metal seal, a small quantity of cement is poured over the top of the metal stopper, which cement soon hardens and makes a perfect seal".

Another stopper lamp (The Electrical Engineer, Vol XV, No 259, pg 376) was patented by Geo. H. Benjamin and assigned to Messrs. Siemens & Halske, of Berlin. The design is shown below.

A system of grooves, along with a fine wire running through them, resulted in sealing with the aid of a carbonaceous material and compression near the grooves. The lamp was tipless, being exhausted by means of the tube T.

The lamp shown below (The Electrical Engineer, Vol XV, No 259, pg 376) was invented by Henry Green of Hartford, CT.

The object of this invention was "to construct a lamp in which the vacuum can be created repeatedly, the globe cleaned and the filament replaced without rendering any part of the lamp useless." ... "The clip H which encircles the outer neck of the globe is used for the purpose of securing the point L with the base piece in the funnel-shaped aperature E while exhausting the lamp."

The "New Beacon" lamp, manufactured by the Beacon Vacuum Pump and Electrical Company (see The Electrical Engineer, Vol XVI, No 277, Aug 23, 1893, pg 169), is a familiar one to collectors of lamps and will not be described in detail here. It is shown below.

The "Maggie Murphy" had an external appearance very much like the "New Beacon". It was manufactured and sold by the Pennsylvania Electric Engineering Company, Penn Mutual Building, Philadelphia, PA (see Electrical World, Vol XXII, No 9, or, The Electrical Engineer, Vol XVI, No 276, Nov 1, 1893, pg 168). The lamp is shown below.

The Packard Stopper Lamp (The Electrical Engineer, Vol XVI, No 287, Nov 1, 1893, pg 397) resembled the New Beacon and Maggie Murphy lamps. The neck was closed by cement and mica. It was manufactured by the New York and Ohio Company, Warren, OH and is shown below.

The Westinghouse Stopper Lamp is undoubtedly the most well-known of the stoppers (see The Electrical Engineer, Vol XV, No 248, Feb 1, 1893, pg 108). It was used at the Columbian Exposition of 1893. It is shown below.