Gil Macarrón et al., 2014: THE MOUNTING OF TWO BIRDS
eagle, this compound has not been detected.
FTIR spectroscopy (Figure 11B). In the
This suggests that at least in the flamingo,
spectrum obtained characteristic bands of
Bécoeur arsenic soap may have been used. The
proteinaceous materials can be seen. These are
Bécouer soap is thought to have been invented
associated to peptide bond: ­NH (ca. 3237
in 1743 by Jean-Baptiste Bécoeur (1718­1777).
cm-1), Amide I ( C=O) (ca. 1642 cm-1):
This method of conservation, based on arsenic,
Amide II (
­NH and C­N) (ca. 1534 cm-
in plane
was popularized in 1830 under the name of the
1) and Amide III ( C­N and in plane ­NH) (ca.
Bécoeur recipe and was basically made of white
1260 cm-1). Figure 12 shows a detail of the
arsenic, tartar salt, camphor, lime and soap
flamingo´s paw, the sample taken from this
(Pérez Moreno, 2012). This hypothesis has to
area, and the results of the analysis carried
be confirmed by further analysis.
out. The spectrum obtained bay FTIR confirms
the positive staining with fuschine acid, i.e, it is
Paint and coatings
a protein. The bands identified are: ­NH (ca.
3269 cm-1), Amide I ( C=O) (ca. 1627cm-1):
In the golden eagle, paint on the beak and feet
Amide II (
­NH and C­N) (ca. 1514 cm-
in plane
can be observed. When living organisms die,
1) and Amide III ( C­N and
­NH) (ca.
in plane
some body parts lose their coloration or
1234 cm
-1). To determine the composition of
darken, as happens in the case of the legs and
the
filler,
SEM-EDS
was
employed
for
some areas of the beaks of birds. The paint
inorganic compounds and GC-MS for the
layers are possibly oil paint, since they are not
organic part. The dark brown putty is composed
water soluble. This has been determined based
of talc (magnesium silicate) in combination with
on solubility tests with water and due to
a mixture of a non-drying fatty material, as
observation with UV light: no fluorescence
shown by GC-MS (Figure 12D). We identified
under UV radiation means that no chromophore
non-drying oil, due to the proportion of the
groups in composition of colors and these parts
methyl esters of fatty acids azelaic, palmitic
have not been varnished or mixed with reactive
and stearic and prevalence of oleic acid and
substances to UV radiation. Also, bills for
small amounts of cholesterol (present in animal
materials generated by the Benedito brothers
fats). Ratios of P/S greater than three can
preparing other pieces indicate that drying oil
reveal the presence of little drying fatty
and tubes of oil painting were used as binder.
material such as animal fat, probably animal fat
For example, these materials are listed in the
and rosin resin. The latter was identified as pine
bills and diaries about the realization of the
resin based on the presence of abietic
African elephant hunted by the Duke of Alba in
acid and other derivatives of these (7-oxo
1913 and performed by Benedito Brothers.
dehiuxroabietico, 15-OH dehidropabietico, etc.).
In stratigraphic examination of the paint on the
Inorganic pigments were not detected. Given
leg of the eagle (Figure 10), the following
the shape and application areas of the brown
layers were detected: 1) a white coat, made of
putty, which is especially thick at the
white lead (2PbCO
3(OH)2) and zinc white
intersection of the leg with the foot, we assume
(ZnO); 2) a yellow layer, in which we detected
that this dark substance was a subsequent
chrome yellow (PbCrO
4) and cadmium yellow
restoration
to
provide
strength
to
the
(CdS) and also white or yellow lead (PbO).
deteriorated legs. There is also a coiled wire
Also, some compounds normally used as fillers
around the leg, which was detected below the
of chrome yellow were found: gypsum and
putty by means of X-ray (Figure 8B), which
perhaps also lead sulfate. Finally, a yellow-
probably reinforced the legs.
orange layer was found, which is composed
of some chrome yellow and, probably, some
lead pigment, perhaps yellow (PbO) or orange
Analysis of the fillings
(Pb3O4). White lead particles appear to be
absent.
Golden eagle neck
In the pink flamingo, as noted above, light
Jute fibers (the information has been compared
brown and translucent material is applied as a
with the sample collection belonging to the
coating on the legs. On top of this layer, brown
Chemistry Laboratory of the Faculty of Fine
putty is applied. The transparent coating of the
Arts (UCM)) were identified as fillings in this
flamingo paws is bright on one side and matte
area. Since there has been no access to other
and rough on the other, corresponding to the
internal parts of the animal´s body, we do not
area of contact with the skin of the animal, so
know if other fillings were used as well, but the
that it could be animal skin. Figure 11 shows a
probability is high because the Benedito
sample taken from the flamingo paw (Figure
brothers usually varied the fillings in different
11A) and the results of the analysis made by
areas of the animal.
85
Journal of Paleontological Techniques