GRECIAN and ROMAN STUCCO, MORTAR, and GLASS* WILLIAM FOSTER Princeton University, Princeton. New rersey
T
HE SPECIMENS mentioned in this paper were found by D ~ T, , L, shear, professor of classical 'OnarchmlOgy in 'Iinceton University, ducting the American excavations a t Corinth and Athens. Stucco may be broadly defined as plaster of any kind used as a coating for walls. Mortar, as used in this paper, is a building material made by mixing lime with sand and water. It is utilized in masonry, plastering, etc. The method of preparing lime is very old. Under the name of "lime-burning" it was employed thousands of years ago for producing mortar. The Hindus, more than 2000 years ago, produced lime by a process which is given in the Susruta, an ancient Hindu work. I t is described as follows: "Collect several kinds of limestones and shells and burn them strongly and add water to the resulting product." The slaked lime thus formed was added to a solution containing potash, obtained by treating wood ashes with water. Caustic potash (KOH) was the final product. Reference is made in the Bible (Deut. 27 : 2) to the use of mortar in plastering : "And i t shall be on the day when ye shall pass over unto the land which the Lard thy God giveth thee, that thou shalt set thee up great stones, and plaster them with plaster."
Vitruvius' De Architectura (2, 5 ) and Pliny's Nal. Hist. (36, 55) describe the process for producing lime and mortar. J. W. Mellor, an English chemist, says: T h e primitive lime-kilns were rudely constructed of stone blocks, and usually located in a cavity cut in the side of a hill. so that the top was convenient for charsing the kiln with limestone. In charging the kiln, large pieces of limestone were formed into
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* Presented before the Division of History of Chemistry a t the Chicago meeting of the A. C. S., September 11, 1933.
a dome-like arch with large open joints; and the kiln was filled with fragments of limestone, the larger pieces of limestone were placed above the arch, and the kiln was topped with fragments of maller size. Kilns were also charged with alternate layers of ameto, and fuel. A wood or other fire was started under the arch, and a bright heat was maintained for three or four days. ANALYSIS OR STUCCO AND MORTAR
In the analysis of the specimens from Greece, it was not deemed necessary to determine the alkalies and magnesia, for these were generally present in relatively small amounts and were merely accidental. All the specimens examined were found to be limesand mortars and stuccoes, similar in composition to those used in modern times. When a mixture of sand and slaked lime sets, carbon dioxide is gradually taken up from the air, calcium carbonate being formed. Lime is transformed into calcium carbonate. All the specimens contained, therefore, much calcium carbonate as well as silica. Lime and silica have some tendency to form calcium silicate. The results of the analvses are recorded in Table 1. The following is an analysis of "water-proof" stucco from Upper Peirene (sample dried at 105'C.) : ~
~
Loss on
ignition....................... 32.42%
In9olubie in aqua regia.. .......'........ Oxides of iron and aluminum.. Lime
......... ................................ Magnesia ............................. Alkalies, ete.. .........................
21.95% 5.51% 36.13%
0.90% 3.09%
One of the most interesting things brought to light by these analyses is the similarity in composition of the stucco from the Greek Fountain House (fourth century B.c.) and of the stucco from Tomb 11 (unpainted), which is Roman and dates from the fourth century A.D.,about eight centuries later. This clearly suggests that the Romans may have learned something from the
TABLE 1 CorPosrrrorr OF G a e c r * ~A N D R o u n M o a r m (F0sr.s)
SPecilncn Lining of Reservoir at Sacred Spring, Vth or Vlth Cent. e.c. Floor of Draw-Bwin. IVth or Vth Cent.
Ozidcr InroluUr offion RlmoinLo= on i v A p w and d n (MopIgnilion Regio Alvminum "&a. (At0 (Si(h. ( F n O d Lime Alkoliar, Told CW etc.1 AhOd (CnO) rrr.) %
+
36.75
14.87
4.56
36.80
7.02
100.00
26.44
36.22
5.58
22.62
9.14
100.00
32.03
26.34
5.34
32.84
3.45
IOOW
32.42
25.33
5.21
33.22
3.82
100.00
32.30
25.58
4.86
35.14
2.12
lW.OO
30.19
30.41
6.86
27.77
4.78
100.00
30.19
31.70
8.07
24.27
5.77
1W.00
38.22
12.50
1.85
43.98
3.45
10.00
33.37
27.57
5.37
32.08
1.81
lW.OO
32.70 8.92
24.94 61.28
7.53 13.41
29.43 13.07
5.40 3.32
1W.00 1W.00
B.E.
Small Aqueduct, llIrd Cent. s.c. Greek Ibvntlin House, l V t h Ceot. m "
Roman stucco from Chamber Tomb. IVth Cent. A.D. Roman Repair of Pircne. 1st Cent. AD.
Wail of Chamber 11, Peirene. Ilnd Cent. A.D.
Painted Wall Chamber of %mb, IInd Cent. A.D. Pebble Pavement,
Matrix stucco from Greek Spring Outside loride (Pipe for conveying
water.)
Greeks concerning the composition of mortars and plasters. It is also interesting to note that the average quantity of sand is about 25 per cent., while the lime (CaO) is about 36 per cent. Now, 36 per cent. of lime corresponds to about 48 per cent. of slaked lime, Ca(OH)%. This indicates that approximately 1 part of sand was mixed with 2 parts of slaked lime. This does not agree with the record left by Vitruvius, a Roman architect, military engineer, and writer, in the days of Caesar and Augustus. According to him, the ancients were instructed to mix, after slaking, 1 part of lime with 3 parts of pit sand. In case river sand or sea sand was employed, 2 parts of sand and 1 part of burnt brick, powdered and ground fine, were mixed with 1 part of lime.* For preparing modern mortar, the best proportions are 3 parts of fine sand to 1 part of quicklime, recently slaked. This is in agreement with the instructions given by Vitruvius. It is of further interest to note that the Greeks manufactured pebble pavements. The matrix was limesand mortar, while the pebbles were composed largely of calcium carbonate. The pebbles also contained about 15 per cent. of silica, which increased their hardness. As the stuccoes and mortars analyzed were high in lime and low in silica, tbey were rather soft. A SECOND CENTURY A.D. ROMAN GLASS
A thin film of beautifully iridescent material was removed from a small cup-shaped piece of the glass. It is not uncommon for excavators to find specimens of iridescent glass. Some of them resemble the richest and most varied wings of butterflies. One piece of glass was found in the palace of the Caesars which was similar to burnished silver, but with a pearl-like tint. Iridescent glass is the result of change or decay. In some cases it is due to the action of ammonia. Thus, rainbow-like films are sometimes found on the windows of stables, where ammonia is formed by the transformation of nitrogenous organic matter. The composition of the specimen of Roman glass was found to be as shown in Table 2. Analyses of other soda-lime glasses, ancient and modern, are given for the purpose of comparison. Analysis of various specimens of ancient glasses shows that the chemical composition is quite similar to that of modem glasses. As a rule, however, ancient glasses contain more soda and potash. Thus, analysis has shown that certain specimens of Egyptian glasses contain between 20 and 24 per cent. of soda.' The great bulk of old glasses consists primarily of silica, lime, and alkalies. This is true also of modern glassware, but the silica content in modem glasses generally is above 70 per cent., while the content of alkali rarely exceeds 17 per cent.
SPecimcn Roman G h o Ilod Cent. AD.
....
2.48
. .. . .... . . .
9.13 5.20
1.58
. . .
69.52
16.70
8.81 1.16 3 . 2 7 0.37
(Pmter) Venetian 73.40 Egyptian 1400
18.58
5.06
63.72 20.63
B.C.
S. Window 1929 72.14 CommooBottie 72.26 U.
16.23 17.88
9 . W 1.29 0 . 9 2 7.24 0.17 1.42
99.83 99.52
0 . 4 1 100.67
.... . . . . . .. . . . . .
The composition of ancient glass is approximately as follows: Silia... .. . . _ ... .. . . . . .. . . 65-70% Lime and magnesia ... . . . . . . &lo% Alkalies ..... . . .. .. . . .. . . . . 16-23%. principally soda There are comparatively large amounts of iron and alumina in old glasses, but these are present as impurities. There are reasons why ancient and modem glasses are similar in composition, These are summarized by Donald E. Sharp as follows: (1)
Glass must be fusible at commercially obtainable temperatures.
Glass must be capable of being fashioned into usable forms without crystallization occurring. (3) Glass objects must be reasonably permanent in the use to which tbey are put. (2)
This specimen of glass was found by Shear in Greece.
*Ancient Egyptian mortars were prepared by mixing clay (Nile mud) with gypsum. According to Lucas, lime was unknown in Egypt until Roman times.
ojFe Lass Mog- and A1 on Silica Soda Lima ncrio (Fn0z-F IgnC P o l o d T o l d (SiOi) (NasO) (CaO) (MgO) A h a ) lion (K101 %
AN ANCIENT COSMETIC
In concluding this paper, it might be of interest to say SBARP. Ind. Eng. Chnn.. 25, 755 (1933).
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a few words about ancient cosmetics. Chemicals have Greeks and the Romans manufactured a form of lead been used as cosmetics for thousands of years. Thus carbonate (basic lead carbonate) by a method somethe women in the East have long used antimony tri- what similar to the old "Dutch process" for the producsulfide for painting their eyebrows. This is evidently tion of white lead, so useful as a paint. The substance referred to in the Old Testament. (See Kings 9 : 30, was known to the Greeks of antiquity as "psimythion" and Ezekiel 23 : 40.) and to the Romans as "cerussa." P l i y informs us While excavating a t Corinth in 1930, T. L. Shear that it was made by placing shavings of lead over a found in a woman's grave a small terra cotta toilet box, vessel filled with the strongest vinegar. Carbon dating from about 400 B.C. The grave also contained dioxide was also required, as in the Dutch process for a silver coin and several vases. The vanity case con- the manufacture of white lead. tained little cubes of a white material which was eviApparently the ancients were not acquainted with dently used as a cosmetic. Chemical analysis proved the poisonous nature of lead carbonate. that it was lead carbonate. This compound occurs in According to Shear, the material found in the Greek the natural state, and is called cerusite. toilet box is the first or earliest white cosmetic ever I t is of interest to know in this connection that the recorded.
