Rubber Poncho and Blankets from the Union Transport Maple Leaf

By Lawrence E. Babits

Originally Published in the Journal of the Company of Military Historians, Vol. XLVII, No. 2

Very little has been published on the rubberized blankets and ponchos used during the Civil War. This is surprising because they were crucial items in the Civil War soldier's equipage. Some idea of the importance of rubberized blankets can be found in references by Hinman, McCarthy, and Bellard.(1) The lack of published material on rubberized artifacts undoubtedly lies in their poor preservation qualities, both in the ground and in museum storage areas because of sulfuric acid used in the vulcanization process. Recent excavation of a sunken transport ship has provided new information about both ponchos and gum blankets.

On 1 April 1864, the sidewheel steamer Maple Leaf struck a Confederate torpedo in the St. Johns River near Jacksonville, Florida. The vessel, under contract to the Union Army, carried sutler stores, the personal baggage of three Union infantry regiments (112th New York, 169th New York, 13th Indiana), and a brigade headquarters. Among the artifacts recovered are eleven rubber blankets, a poncho, and an unidentified rubberized cloth which will be described here. Two additional examples from collections will be used for comparative purposes. The thirteen gum blankets represent the largest sample studied to date.

Natural rubber is derived from the sap of certain trees, vines, and shrubs found in South and Central America, Africa, and Southeast Asia. One common source is the rubber tree, Hevea brasilensis, but the gum-elastic tree, Ficus elastica, produced the best quality India rubber.(2) These trees were the sole sources of rubber until synthetic rubber was created in the early twentieth century.

Rubber was first known to Europeans in 1735 and was soon sought and used in waterproofing. The physical properties of rubber:

... are softness, toughness, elasticity, impermeability, adhesion and electrical re-sistance. Its most characteristic, but not most important property, is that it can be repeatedly stretched to many times its length, returning each time to about its first dimensions. No other substances at all comparable to rubber in this particular property.(3)

Experimentation with rubber began early in the nineteenth century, but little commercial success occurred because rubber became stiff and brittle at temperatures below freezing; at higher temperatures, it became sticky and melted. These problems were solved when the vulcanization process was perfected in 1839.(4) Charles Goodyear found that, if rubber were mixed with sulphur and heated to between 250 and 280 degrees Fahrenheit, a new compound was formed. Chemically, vulcanization is the cross-linking of isoprene chains by sulphur, which results in a strong, elastic three-dimensional network. This new form of rubber withstood temperature extremes, was resistant to oils,(5) and was not soluble in spirits of turpentine or other oils. Vulcanized India rubber was elastic, pliable, durable, and nonadhesive.(6)

The vulcanization process involved several steps. Raw rubber was first cut very fine with a cutting machine and then cleaned. The rubber particles were then mixed with white lead, sulphur, and other substances as needed. Although sulphur was added in a number of ways, it was generally introduced in the rubber crushing stage or as gaseous sulphur in the oven when goods were heated. The most popular method was to sprinkle powdered sulphur on the article before it went into the oven, as the rubber is more easily penetrated or impregnated with the sulphur, without its being mixed with the gum.”(7)

The rubber was ground, heated, and spread with colanders onto cloth or into sheets. The compound was then heated in a dry oven for four to six hours at about 270 degrees Fahrenheit. As a final step, the rubber was boiled in lime, potash, and other alkalies to remove sulphureous odors.(8)

In 1843, Thomas Hancock patented a similar process in England. Hancock immersed rubber in melted sulphur until it was permeated, then heated it to 302 degrees. The process imparted the same qualities to rubber as Goodyear's process. The term vulcanization was actually coined by a friend of Hancock's, a Mr. Brockedon, who used it to describe Hancock's process. Vulcanization gave great impetus to the rubber industry, and rendered possible its almost unlimited development.”(9)

Goodyear received an American patent on the vulcanization process in 1844 and began issuing licenses to other companies. One of the first India rubber articles made for military use was a rubber knapsack. During the Mexican War, the Quartermaster General suggested using India rubber cloth for knapsacks, because the knapsack would be waterproof and was quicker to make than painting waterproofing agents on knapsacks. Goodyear later noted the knapsacks were found objectionable in consequence of their too great warmth, offensive odor, and imperfect manufacture.”(10)

Little rubber clothing was manufactured in the United States before the Civil War.(11) Although the Quartermaster Department did not intend to supply troops with rubber blankets at the beginning of the war, by November 1861 the Secretary of War ordered all soldiers to be issued “waterproof blankets.”(12) The change was made because some states issued their troops rubber blankets and other units began to request them. Mounted troops received waterproof ponchos, which were little more than rubber blankets slit in the center for the wearer's head.(13)

Although the Union India Rubber Company received exclusive rights to manufacture rubber clothing as early as 1853,(14) other companies manufactured rubber blankets and ponchos for the U.S. Army during the Civil War, because:

...the demand thereby occasioned for blankets, ponchos, rubber overcoats, haversacks, tents, etc., was so great, that the inducement to Companies, which were already in possession of the requisite machinery, to manufacture such articles, was strong...The Union Rubber Co...had...the exclusive right to use his [Goodyear’s] process in the manufacture of Clothing. Some manufacturers attempted to ignore this fact, and proceeded to contract with the Government to furnish supplies of the articles named. Apparently successful in evading the many legal decisions which had established the validity of the Goodyear Patent, and the consequent right of Mr.Goodyear to dispose of it as seemed most proper, it was not until payment was expected on account of the contracts that the infringing parties found that there was a serious obstacle in their path. The Union Rubber Company had quietly stopped all payments on such contracts, unless the parties furnishing such supplies could produce a written permit or order from them. The only course that remained was to attempt some compromise with the Company whose rights had been invaded, which could usually be effected upon terms not unreasonable, in view of the circumstances.(15)

Other companies, including the Boston Rubber Shoe Company, acknowledged the Union India-Rubber Co.'s exclusive license, but solicited subcontracts in case Union could not furnish all the goods required by the government. This proved to be the case, and the Boston Rubber Shoe Company manufactured thousands of blankets with the blessing of the Union India-Rubber Co.(16) Blankets manufactured under license from Goodyear were required to bear a patent stamp on one corner on the fabric side. Since Goodyear's patent expired 15 June 1865, all Civil War rubber goods were legally required to bear the stamp.(17)

In addition to the Union India Rubber Company and the Boston Rubber Shoe Company, at least two other companies are documented as manufacturing rubber blankets during the Civil War: the Phoenix Rubber Company and the Rubber Clothing Company. New York City's Rubber Clothing Company(18) held a license from Goodyear.(19) The Phoenix Rubber Company also produced other vulcanized rubber goods, as opposed to products made in a different manner, and were most likely either under license from Goodyear or subcontracted by Union.

A report comparing rubber cloth samples marked “Union,” “Phoenix,” “Glove,” and “Boston” found that “Glove” and “Boston” samples were produced by an inferior method. This different process dissolved the rubber in any number of solvents (generally naphtha), spread it on the cloth with a brush, and treated it with a solution of chloride of sulphur, which did not impart the characteristics of the vulcanization process.(20)

Since many patent infringers made rubber goods illegally, or manufactured them with inferior methods, not all rubber blankets from the Civil War period will bear a patent stamp. At least one blanket of questionable legality turned up on the Maple Leaf. Boott Mills of Lowell, Massachusetts, does not appear on any listing of rubber blanket suppliers to the Army, but Boott Mills Sheeting is clearly marked on the rubberized side of a gum blanket recovered from the wreck (FIG 10).

Most Maple Leaf gum blankets probably had patent and manufacturers' stamps with the marks placed on the white cloth, and therefore visible, nonrubberized side. A peculiarity of Maple Leaf artifact preservation is disintegration of vegetable fibers (cotton, hemp and linen) while animal fibers such as silk and wool survive. The uncoated cotton blanket fibers did not survive, thus eliminating makers' marks.

A similar substance, gutta percha, was also used to water-proof cloth. Both India rubber and gutta percha blankets were used during the Civil War. Gutta percha is described by Goodyear as a variety of gum-elastic, possessing very similar qualities to India rubber, which is affected in the same way by vulcanization as India rubber. Reports comparing the performance of rubber to gutta percha blankets were so conflicting the Quartermaster General had not decided on a standard waterproof blanket by the end of the war.(21)

In contemporary literature, the poncho and rubber blanket seem almost interchangeable. The “official name was the 'poncho,' but this word had no meaning to the boys, few of whom were supplied with dictionaries, and they always called it the 'gum blanket.’” Whatever its name, the gum blanket was useful:

[I]t's mighty good ter spread on the ground under yer blanket when ye goes ter bed.Ye know wet won't soak through Injy-rubber, 'n' it'll help pervent ye ketchin' the rumaticks. ‘Sides that, when ye have ter lie down 'n the mud it keeps yer blanket clean.Then when ye're marchin' in the rain it beats 'n umbreller all holler.(22)

The rubber blanket or poncho was more than just a piece of clothing to keep a soldier dry. Rubber blankets were painted with checkerboards and other game surfaces, such as “chuck-a-luck,” “sweat,” and “Honest John.”(23) They were also used to distribute food issues and, on occasion, to mix food.(24)

Historical descriptions of rubber blankets and ponchos vary somewhat from Quartermaster specifications. The poncho described by Hinman was “six feet long by four feet wide, with a slit eighteen inches in length running crosswise in the center.”(25) At first, it seems Hinman confused the poncho with gum blanket dimensions,(26) but his figures are verified by surviving examples recovered from the Maple Leaf (Table 1). Lord mentions the Quartermaster poncho but also discusses another size poncho, measuring 45 inches by 79 inches.(27) It is not known where Lord obtained these measurements as no citation is given.(28)

John D. Billings remarked that an “army poncho…is specified as made of unbleached muslin coated with vulcanized India rubber, sixty inches wide and seventy-one inches long, having an opening in the centre lengthwise of the poncho, through which the head passes, with a lap three inches wide and sixteen inches long.”(29) Although this description appears to come straight from the “Quartermaster's Manual, the poncho noted is a foot wider than extant examples (Maple Leaf artifact #01611 48 x 71 inches; Minnesota Historical Society example 44.25 x 72 inches).

The 1865 “Quartermaster's Manual” was based on equipment contracted for and used in the latter part of the Civil War. In the case of extant ponchos, it would seem that the 48 inch width was not deemed adequate. Consequently, the new specifications called for 60 inches. Specifications for the manufacture of both gum blankets and ponchos stated that:

Water proof blankets and ponchos – the first for infantry, and the latter for cavalry. To be made of a good, strong material, coated with gutta-percha or india rubber, vulcanized. The ponchos to be 71 inches long and 60 inches broad. The grommets to be placed equi-distant, not exceeding 14 inches. They must both be bound all around, or hemmed. The slit or collar in the centre of the poncho, must be strongly sewed with 2 rows of stitching, and must be 3 inches wide, and 16 inches long when completed. The water proof blanket for infantry, to be 46 inches wide by 71 inches long, without the slit for the head; but having the grommets arrangement the same as for the poncho...grommets, in all cases, to be 1 inch from the centre of the grommets to the edge of the blanket on one side and end, and 2 inches from the other side and end. The grommets must be stayed, and be placed equi-distant, so as to match, and be made of brass.(30)

While Billings reported that muslin was the base for the rubberized fabric, any cloth, either loosely or closely woven, could be waterproofed. Closely woven fabrics, such as muslin and duck, were preferred because they required less rubber to fully coat.(31)

Ponchos

It appears from historical documents and museum specimens that rubber ponchos were made in at least two rough sizes: 71 x 60 inches (6 x 5 feet), and 72 x 48 inches (6 x 4 feet). The one poncho recovered from the Maple Leaf was six by four feet (FIG 1), but it differed from the other types in having a different neck hole arrangement.

Several differences are noted between the historical record, the Minnesota Historical Society (MHS) poncho, and the poncho from the Maple Leaf. The most obvious is the variance in the number and placement of the brass grommets. The MHS poncho has sixteen grommets equidistantly placed around the perimeter, as per "Quartermaster's Manual" specifications.(32)

The MHS poncho has 9/16” diameter grommets which are reinforced by 1.25 inch square pieces of rubber cloth. The grommets are spaced an average of 13.25 inches along the sides and 15 inches along the ends, exceeding the "Manual's" specifications maximum distance of 14 inches. Grommet placement on the MHS poncho corresponds roughly to the "Manual's" specifications, being approximately one inch from the center of the grommet to the edge of the blanket on two sides and two inches on the other sides.(33) There are no grommets on the Maple Leaf poncho.

A possible method of constructing the rubber poncho is offered by Stephen Osman based on the Minnesota Historical Society's poncho. In this method, no stitching was used in finishing the edges of the blanket/poncho. A strip of rubber cloth 3/4 inch wide was folded to a half inch, then glued along the edge of the body piece, flush with the edge, covering one comer of the grommet reinforcing piece. The Minnesota Historical Society notes that "all seams and overlays are bonded and heat sealed."

Gum Blankets

Thirteen gum blankets, or drawings of extant examples were examined for this article. Of these, only two are not from the Maple Leaf; one in the Museum of the Confederacy (FIG 3) and another in private hands (FIG 4).(34) The other eleven examples were recovered from the steamer Maple Leaf. Several Maple Leaf ponchos are torn and missing one edge. Without considering size, it is possible that there are three types of gum blanket. The first two types differ primarily in the presence or absence of paired grommets along a portion of one long side. The third type differs dramatically in that the grommets are smaller, more closely spaced and sewn.

Type A gum blankets (FIGs 3, 5, 12, 13, 14) have single grommets spaced around the edges, with spacing similar to that called for in the regulations. Type B gum blankets (FIGs 4, 6, 7, 8, 9, 10, 11) are distinguished by having at least two paired sets of grommets on at least one long side. The purpose of these double grommets may have been to allow wearing the blanket without cutting a slit to serve as a poncho. On both Type A and Type B gum blankets, grommets are located in accordance with Quartermaster specifications in that they are one inch from one end and two inches from the other.

The 1889 Quartermaster's Manual made only one distinction between rubber blanket and poncho aside from the head slit in the poncho. The rubber blanket was to have two additional grommets on one side. From the drawing, the two extra grommets were to be about four inches from the two centermost grommets on that side. The drawing of the 1889 rubber blanket shows a string or ribbon passing through one grommet indicating the paired holes were to allow the rubber blanket to be used as a cape.(35)

Only one Type C gum blanket is known (FIG 15). The length and width are only approximate. The distinction between other types lies in the edge binding. The Type C binding is twice as wide and of double thickness when compared with Types A and B. The grommets are eight inches apart, about 1/4 inch in diameter and sewn. It may be that the Type C gum blanket is an experimental or contractor version but it may be a field expedient piece. It is entirely possible that this fragmentary piece represents a portion of a rubberized shelter half.

The treatment of grommets in all three types is variable. There are plain grommets, grommets with diamond/square, rectangular, and round reinforcement. The reinforcement appears independent of size and type. Any definitive statement about the grommet reinforcement should await a larger sample, but it is clear that there were many variations among the ones carried by Foster's Brigade.

No Maple Leaf gum blankets exactly match Quartermaster dimensions. This should not be surprising since these dimensions were drawn up after the Maple Leaf sank. Sizes are so variable, considering the small sample size, that size might not be a valid criteria for evaluation. If the cloth were cut to standard specifications and then shrunk during processing, as occurred during the manufacture of shelter tents, this would account for articles with size variations smaller than the specifications. However, while shrinkage would seem excessive for some gum blankets found on the Maple Leaf, it is not when compared to the Museum of the Confederacy (FIG 3) and Woshner (FIG 4) examples.

Some of the Maple Leaf measurements are only close approximations since the blankets are in a damaged condition. However, alignment of sides and ends usually allowed fairly accurate measurements. Artifact #01138 (FIG 5) is typical. It is in poor condition as a result of immersion. The blanket is fragmentary and no cloth backing remains.The blanket edges are particularly deteriorated. The dimensions of 70 inches by 47 inches are approximate, particularly the width, because one whole side is missing. This makes the original number of brass grommets unknown, although seven remain. Spacing between extant grommets varies between 13 and 14 inches, but the distance from the edge is unknown, as the original edges do not remain. The grommets are brass and measure from between .55-.60 inches in diameter. They are reinforced by circles of rubber cloth approximately 3/4 inches in diameter. Stitch holes run along all extant edges, but it is not known what purpose they served.

Most rips and tears in Maple Leaf blankets are due to their deteriorated condition. However, at least one rip in the body of artifact #01138 has small stitch holes running along each edge. The line of stitching is approximately one inch in length with twelve holes per side. This probably represents a repair.

The two blankets recovered from the Maple Leaf which were the most intact have eighteen grommets each: six along one edge, eight along the other edge, and two on each end. It is not known how many grommets Artifact #01138 originally had as one edge is missing. Spacing of the seven remaining grommets on #01138 matches Quartermaster specifications, varying between 13 and 14 inches apart.

The edges of artifact #01138 appear to have been constructed in a different manner than the Minnesota Historical Society example. While the exact method of construction cannot be determined, the presence of stitch holes along all extant edges makes it very likely that #01138 had sewn rather than glued edges. An alternative explanation is that #01138 was repaired by the owner after the original glue came undone. This possibility is reinforced by the presence of stitch holes along the edges of one rip in the body of the blanket.

The above observations must be considered preliminary in nature. Less than five percent of the cargo has been recovered to date. The small sample size makes firm statements problematic but there do appear to be at least three types of rubberized blanket. Within the three types were varying sizes, grommet placement, backing, and type. This variation should be expected given the newness of rubberized cloth in military applications and the number of manufacturers, some of whom were, apparently, operating without license.

I wish to thank Saint Johns Archaeological Expeditions, Inc. and the Museum of the Army, Center for Military History, Department of the Army, for allowing me to examine and publish observations about these materials. Others who were particularly helpful include Douglas D. Scott of the Midwestern Regional Archaeology Center, National Park Service, and James O’Barr of the National Park Service's Desoto Bend National Wildlife Refuge, Stephen E. Osman of the Minnesota Historical Society, and Michael Woshner. Leslie Jensen provided a sketch of the Museum of the Confederacy poncho. Matthew Russell, a graduate student at East Carolina University conducted initial research and analysis on one rubber blanket which ultimately led to this article. The graphics were provided by Harry Pecorelli III, a graduate student at East Carolina University. I benefited a great deal from discussions with Company Fellow Frederick Gaede. Their assistance is acknowledged. Any errors are my own.

Notes

1. Wilbur F. Hinman, Corporal Si Klegg and his Pard (Cleveland: National Tribune, 1895), p. 50 (hereafter cited as Hinman); Carlton McCarthy, Detailed Minutiae of the Army of Northern Virginia, cited in Soldier Life in the Union and Confederate Armies (New York: Crown Publishers, 1961), p.298; Alfred Bellard, Gone for a Soldier (Boston: Little, Brown & Co., 1975), p. 167.
2. Charles Goodyear, Gum-elastic and its varieties, with a detailed account of its applications and uses and of the discovery of Vulcanization (Boston, 1939 [1855]), p. 16 (hereafter cited as Goodyear).
3. H. C. Pearson. Rubber Machinery (New York, 1920). p. 7.
4. W. T. Brannt, India Rubber, Gutta-Percha, and Balata (Philadelphia, 1900), pp. 1-2; Goodyear, p.43 (hereafter cited as Brannt).
5. Goodyear, pp. 51, 68, 84.
6. Goodyear, p. 138.
7. Goodyear, p. 155.
8. Goodyear, pp. 152-162; Henry C. Pearson, Crude Rubber and Compounding Ingredients (New York, 1920), p. 31.
9. Brannt, pp.5-6; Thomas Hancock, Personal narrative of the origin and progress of the India-rubber manufacture in England (London, 1939 [1857]), p. 107.
10. Goodyear, p. 136; Ema Risch. Quartermaster Support of the Army: A History of the Corps, 1775-1939 (Washington: Center of Military History, 1989), p. 258 (hereafter cited as Risch).
11. Chauncey M. Depew, 1795-1895 One Hundred Years of American Commerce (New York, 1895), p. 501.
12. Risch, p. 359; Frederick P. Todd, ed., American Military Equipage (Providence, RI, 1974), p. 73.
13. Francis A. Lord, Civil War Collector’s Encyclopedia (Secaucus, NJ, 1982), p. 57; Risch, p. 359 (hereafter cited as Lord).
14. Goodyear, p. 307.
15. J. L. Bishop, A History of American Manufacturers from 1608 to 1860… (Philadelphia, 1966 [1868]), vol. 1, pp. 308-309 (hereafter cited as Bishop).
16. Bishop, p. 309.
17. Mike Woshner,”Civil War Rubber” North-South Trader (March-April 1976): 16 (hereafter cited as Woshner).
18. Lord, p. 344.
19. Woshner, p. 14.
20. Anonymous, Scientific Reports on the Comparative Value of Vulcanized and Unvulcanized India-Rubber (1865), pp. 5-10.
21. Goodyear, p. 28; Risch, p. 359.
22. Hinman, pp. 50-51.
23. Ibid.
24. John D. Billings, Hardtack and Coffee, ed. Philip Van Doren Stern (Bloomington: reprint, Indiana University Press, 1961), p. 81 (hereafter cited as Billings).
25. Hinman, p. 50.
26. Stephen E. Osman, personal communication, 1992
27. Lord, p.196.
28. U. S. Army Uniforms and Equipment, 1889 (Lincoln, 1986), pp. 238-241 (hereafter cited as Uniforms and Equipment, 1889).
29. Billings, pp. 54-55.
30. "Quartermaster's Manual,” (Washington: GPO, 1865), p. 54.
31. Brannt, p. 194.
32. Stephen E. Osman, personal communication, 1992.
33. Stephen E. Osman, "Poncho or Gum Blanket Instructions," undated drawing of poncho in Collections of the Minnesota Historical Society, Minneapolis. Copy on File, Maritime History Program, East Carolina University, Greenville.
34. Woshner, p. 15.
35. Uniforms and Equipment, 1889, pp. 238-241.