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Of the different styles of globes that fit a "tall globe" railroad lantern, the "Corning-Style" globe is perhaps the most common. The distinguishing features of this globe are the pear-like shape and the lack of an "extended base" -- the quarter inch of so of flange than extends below the main body of earlier tall globes. The evolution of the Corning-Style globe extended over a decade or so at the beginning of the 20th century and makes for an interesting story. Incidentally, like so many other terms in railroadiana collecting, the phrase "Corning-Style" was invented by collectors; it was not the term used in the industry.
The story begins in 1902 when Alanson Houghton obtained a patent on a "new and useful improvement in the manufacture of lantern globes." According to his patent application:
"My invention relates to a method or process of making a lantern-globe, consisting on subjecting the blank to pressure only in the direction of the natural flow of the glass under expansion. When pressure is exerted upon a blank or body of glass at the end of a blowpipe, such body assumes a positive and certain formation due to gravity and pressure, which shape is substantially that of a pear, and in carrying out my method while a mold is used it exercises little or no influence in the shaping of the globe, but acts more especially , if not entirely, as a medium for limiting the extent of the expansion of the glass under pressure, so that the mold may be termed rather a "size-controller" than a means of formation. Under my invention, in which the globe produced is not provided with a bottom flange or ring, the glass is not subjected to choking at an angle, but is expanded evenly only to the natural shape it takes due to the internal air pressure applied, the globe having throughout a shape that simply conforms to the natural and unimpeded flow, or rather expansion, of the glass in shaping under pressure. A principal reason for the omission of the bottom flange or ring is therefore to prevent the formation of an angle in the wall of the globe, which has been a prime source of weakness therein. .....After exhaustive experiments and actual tests I have arrived at the conclusion that the practice heretofore employed of making a flange or ring at the bottom of the globe is the greatest source of weakness in the globe."
Basically Houghton's argument was that the process of making a globe with an extended base required so much pressure to force the molten glass into the bottom part of the mold (the part with the extended base) that the walls of the globe ended up with varying thicknesses. The walls of the top part of the globe were thinner than the walls at the bottom, and this led to more breakage. By using gravity and less force (and eliminating the extended base), the globe had the same thickness all around and thus was more likely to withstand a wide range of temperatures and rough treatment.
According to Cunningham (Note 1), Houghton later applied for two more related patents covering the shape and equally-thick walls of the globe. All three patents were assigned to the Corning Glass Company which thereby had patent protection for seventeen years beginning in 1904. The major patent was the first one -- #717, 501, and early globes made under this patent had small, cast letters toward the top of the globe, "PAT'D DEC 30, 1902, NO 717, 501".
The next big development in the Corning-Style globe was Corning's patent for the familiar "Cnx" trademark in 1909. According to a 1981 letter from Corning to the Key Lock & Lantern editor, "The CNX trademark is an abbreviation for Corning NONEX. NONEX preceded Pyrex among the various trademarks Corning registered with the U.S. Patent Office. Both trademarks were used concurrently, with NONEX predominating on railroad glassware." Although Corning's exclusive patent to this style of globe eventually expired, they apparently retained the lion's share of the market, judging from the number of "Cnx" globes that show up today. Corning referred to this globe as a "#39 globe" and according to the letter, "It became less widely used between 1920 and 1930 as the shorter types [of globes] became standard with most railroads; however, some 39's were made until about 1950." [Note 2].
Since the reign of the Corning-Style globe extended over a period of roughly fifty years, a wide range of railroad markings are found on these globes, both etched and cast. Among collectors cast markings in a square panel are considered rarer and more desirable. Markings in a panel with rounded ends are more common. A point of some mystery is the small, cast letter that is sometimes found above the Corning trademark. Even the Corning representative could not shed much light on this: "The alphabetical letter above the trademark may have been a mold identification used for a limited time for internal factory purposes. We do not know the date it was used." [Note 2].
The Corning-Style globe was a very successful innovation that attained widespread acceptance in the railroad industry. Today, a century after the first patent was issued, such globes continue to be valued by collectors as a reminder of the heyday of railroading.
1. Cunningham, W.A. The Railroad Lantern: 1865 to 1930. (Published: 1997).
2. Key, Lock & Lantern, Winter 1981-82, #62, pp 882.