Carnival Glass insulators are not cheap imitations of a more expensive kind of insulator and in this sense the term may not be applicable . However, the insulators and the dishes are colored or iridized by the same, or similar, processes; that is, by coating them with a thin layer of metallic salts, and in this sense it seems quite proper to call the orange or golden colored insulators "Carnival Glass".

This method of producing the color on insulators is described by J. L. Littleton (1931) in his application for a patent for producing (among other types) "marker type" insulators, as follows:

"In practicing my Invention I prefer to apply my coating to predetermined portions of the insulator as it is taken from the mold, that is, when the temperature is about 600 (degrees) C. to 750 (degrees) C., but on account of uneven cooling in some types of insulators it is desirable to place the insulator in a reheating kiln held at 650 (degrees) C. in order that the parts to be coated may be brought to proper temperature. The insulator is then coated by spraying with a metallic salt solution or by exposing it to the fumes of a metallic salt.

"The salt solution used for spraying the insulator preferably is forced from the nozzle by a stream of compressed air which produces a fog-like spray of minute particles, the volume of which may be controlled by adjusting the flow of air through the nozzle. Fumes of the metallic salt may be generated (1) by heating a solid salt, for example - ferric chloride, in a closed container provided with delivery tubes; or (2) in case the salt has a normally high vapor pressure, by passing air through the container as in the case of stannic chloride, titanium chloride or silicon tetrachloride; or (3) by passing chlorine through a tube containing the metal or an oxide of the metal and carbon as in the case of iron, tungsten or molybdenum.

"In performing this operation I prefer to place the insulator on a rotating table before a nozzle which is positioned to direct the spray or fumes onto the insulator. By the rotation of the table combined with proper direction of the jet, the outside of the hot insulator is coated with a uniformly thin film of oxide which is closely incorporated with the surface of the insulator in the form of a lustrous or iridescent coating whose thickness is approximately .001 to .63 mm. If it is desired to treat the entire surface of the insulator, as for instance in producing marker insulators ......... the pin-hole may be held toward the spray or an additional nozzle maybe placed in the center of the rotating table. After the insulator has been sprayed as above described it is placed in a lehr and annealed In the customary manner.

"......... Since the color of the coating produced by use of ferric chloride varies from a light golden brown to a deep reddish brown, depending on the thickness of the coat, I am thus enabled to produce -- in a simple manner a distinctively and permanently colored "marker type" insulator whose color is not affected by weathering.......

"The coatings produced by the above described process are extremely thin, from .001 to .3 mm., and on this account give rise to the phenomenon known as interference colors, that is, they have an iridescent appearance. When the coating exceeds a certain thickness it no longer appears iridescent. The thickness of coating may easily be increased by long or repeated exposure to the fumes or spray......." This is the end of the quotes from Mr. Littleton's patent. The patent is very long, containing five pages. He makes 25 claims for his patent, including desirable electrical properties, as well as permanent colors for markers.

Most manufacturers of carnival glass did not patent their processes, or did not name the materials used in coloring, but preferred to keep them secret, perhaps because the dishes were so cheap that it was not worth the cost of obtaining a patent and then fighting through the courts any infringements thereon, but also because of the romantic sound of a "secret formula". To quote from a description of the modern ware produced by the Fenton Art Glass Company, "Several different colors with their changing hues were created by spraying secret mixtures of metallic salts on various colors of hot glass." Whatever the reason, no patent for a cheap method of iridizing glass dishes has been found. Ruth W . Lee (8) states: "Frederick Corder, like Tiffany, designed all his own glass. Neither took out patents on his wares, though they remained a trade secret with each."

A. C. Revi (11) states: "Contemporary reporters and most all patent specifications omit certain pertinent elements necessary to the manufacture of colored Iridescent Glassware." It is known, however, that the color and iridescence was produced by spraying with metallic salts. Mr. Revi further states: "Lobmeyer, he said, would introduce tin crystals into a muffle and the fumes from these oxidizing crystals attacked the surface of the glass subjected to them causing a coruscated effect. Fred Corder produced the same effect by spraying the heated glass with a solution of tin crystals dissolved in distilled water." Marion T. Hartung (7) states: "The mass-produced Carnival was given its iridescence by coating with some variety of metallic salts. Then the piece of glass was re-fired, and when it cooled, there was the desired finish. Exactly what the metals were need not concern us", but they were obviously not expensive.

C. C. Manley (10) writing about English Iridescent Glass states: "Originally, manufacturers tried to mix the metallic lustering oxides with their glass melts, but they soon discovered that the various oxides could be applied to the surface of the articles using a cheaper and easier method. After the object was formed it was placed in a chamber into which the fumes of various oxides were blown. The fumes attacked and/or attached themselves to the surface of the glass, resulting in a highly iridescent finish. Up to a point, the length of time the object was left in the chamber determined the degree of iridescence.

"Another common method used to produce somewhat the same results was to paint a lustering compound on the surface of the glass while it was being worked at the furnace mouth and was still in a plastic state. The easiest, cheapest, and most common method of iridizing glass was to spray a metallic solution on the glass before it went through the annealing ovens. Obviously, the depth of the iridized surface is very shallow."

Mr. Manley also states: "We were told by a relative of John Northwood that when this type of iridescent glass was being made, the fumes generated by the lustering compound were so bad that the men working in the factory refused to continue."

Iridized glass attained its peak of popularity in the early part of the 20th century. The Fenton Art Glass Company, in their small brochure which they attach to modern glass say: "From 1907 until 1920, Iridescent Glass, the original name of Carnival Glass, was the Company's major product." However, it is generally accepted that it originated in Bohemia in 1878 and was made in the early 1880's. It was produced to some extent in England before it became popular in America. It should be noted that this is not the Bohemian glass described by H. H. Whitlow (13) who states: "Bohemian Glass applies to colored glass cut to clear. It was made over a long period In various countries. Some Bohemian glass is an overlay, but later competitive wares were flashed and cut or etched. Flashing or Casing is described (1) as: "the name given to the method by which the gathering is dipped in another color before it is drawn into glass, resulting in a surface of glass in a different color from that of the object. This coating is later partially cut through to form a design of a contrasting color. This technique was used for Cameo glass and other forms of glass having a similar decorative effect."

Having obtained the above information (and much more that is more or less repetitious) it is the author's opinion that the term Carnival Glass is quite proper to describe certain colors of insulators.

For information about other colors in insulators the reader is referred to TRANSMISSION LINE INSULATORS by C. H. Turner, which was published in the OLD BOTTLE MAGAZINE - March, April and May 1970, Volume 3 - Numbers 2, 3 and 4.

SUPPLEMENTARY READING & BIBLIOGRAPHY

(1) Boger, Louise Ade & H. Batterson, The Dictionary of Antiques and the Decorative Arts.

(2) Bromley, Betty L., "Carnival - The Cincerella Glass," The Glass Club Bulletin Christmas 1965, pages 5-8.

(3) Freeman, Larry, Iridescent Glass. Watkins Glen, New York,

(4) Hamburg, Brock, "Carnival Glass," Antiques Journal, September 1965.

(5) ___________________

(6) Hartung, Marion, Carnival Glass in Color. Leon, Iowa, Mid-America Book Company, 1967.

(7) _________________ Carnival Glass, One Hundred Patterns. 1960.

(8) Lee, Ruth W., Nineteenth-Century Art Glass. New York: M. Barrows and -Company, Inc., 1952.

(9) _________________ Victorian Glass. Northboro, Massachusetts: Ruth W. Lee, 1944.

(10) Manley, C. C., English Iridescent Glass, Spinning Wheel, January and February 1969, Volume 25, Number 1.

(11) Revi, Albert C., Nineteenth Century Glass - Its Genesis and Development. New York: Thomas, Nelson & Sons, 1959.

(12) Watkins, L. W.,  American Glass and Glassmaking. New York: Chanticleer Press, 1950.

(13) Whitlow, Harry H., Art Colored and Cameo Glass.