The effect of climate on alpine conifers also on the maples, as well as the various other species of wood used in the manufacture of European bowed stringed instruments, like the ripening flavor of natural weathering, and mainly, the chemicals used to protect them after their suppression, have been identified as factors responsible for the unique sound of the instruments manufactured by Stradivari and Del Gésu. European exceptionally cold winters from the period 1645 to 1715, characterized as a mini ice age, supposing would have affected the tone used by the masters of the Italian peninsula for the manufacture of instruments, making them stronger and more dense (except African ebony, which already has naturally this characteristic, being used only in parts of the instrument than not interfere with its acoustic response).
The numerous dendrochronological analysis, made over the last decade of last century, when suspicion fell on the Strad “Messiah” (believing it could be a forgery, with paternity ascribed to Rocco, or Vuillaume), able to indicate with some accuracy the age of instruments made by Stradivari, and the other violin makers from Cremona, also demonstrating, a significant change in the growth rings form and alpine fir, and as a consequence of this, an increase in compression stems, during the mini ice age. On the other hand, much time was lost in the discussions and controversies about formulas of the varnish used to permeate the wood and protect the instrument from moisture, perspiration, and uric acid. Natural and artificial resins and the dyes, like dragon’s blood (calamus draco), the venetian turpentine varnish (larix occidentalis), and others mysterious formulas, since the days of medieval alchemy and the proto-Renaissance, also was the object of analysis and discussion. Today, by knowing that all European violin makers at time used the same varnish soft and some of the amber, this discussion seems to have been closed. However, even considering the formulas, and qualitative and quantitatively identical as to reagents used in the Cremona varnish, compared to other coatings used at the time, was not proved until now to wet or photosynthetic oxidation of varnishes, associated with ageing, affect the sound. Only to have an idea of the complexity of ingredients in the formulation of varnishes, dyestuffs, and possible cross-reactions to over time, just mention that the mass spectrometry found residues of wildflowers pollen in Stradivari varnish, which leads us to the field of paleobotany research. As for the chemical treatment of wood, there are three plausible theories applied to the Cremona instruments, especially those of Stradivari and Del Gesù not yet were confirmed: The first concerns the examination by electron microscopy by X-ray diffraction, EDAX, which identified certain mineral substance known as land of “pozzolana”, probably collected in a quarry near the Vesuvius, or in more distant events, at sites of Etna or Stromboli volcanos, which was being used as a sealant or cement mortar alloy, since the Roman Empire.
The “pozzolana”, is nothing more than volcanic ash, a rock too acidic, porous, and lightweight, with high presence of silica that contains the leached and deposited pumices resulting from the micro-crystallization of exhaust gases through the volcanic cone phenomenon which is caused by sudden atmospheric impact. The properties of low density particle size of the mineral, with corroborating these same features found on spruce, taken by radial cut of the log used to chop the belly and back of the violin, which, when put into vibration, could undo the spurious resonance frequencies of the audible spectrum, driven by increased mass with the same specific weight, and homogeneous resonance, in line with the ff holes (not wanting to say this, that the resonance box of the violin will function as a bass reflex, whose principle is rooted in Helmholtz resonators). As for the sealing properties of this mineral, and this gray glassy it is waterproof, which, in addition to homogenize the surface of the wood allowing honing an incomparable, against implementation of several coats of a varnish more soft and thick, slow drying because it contains linseed oil, and dye naturally red or yellow, but with characteristics of high brightness, this technique, which this was already known by the Cremona masters, are strongly identified in the Strad “Messiah”. It's like our Brazilian geologists say allegorically: “If there was, or if there was no effusion of basalt on the Botucatu desert; sandstone appeared cooked”. However, known whether there are other components in this preparation, as mentioned above, and if he truly represents key role in the tonal quality of Stradivari and Del Gesù instruments. The second theory, which applies also to other masters of Cremona based on the saturation of the wood by water, since the spruce logs, suppressed in the Alps, come floated to its destination from the river Pó. That transport situation would have changed after the occupation of Europe by Napoleon, compared to open roads for movement of their armies. As a final theory concerning the chemistry, it mention the presence of residual salt in the formula NaCl (sodium chloride) in molecule than of halite, (mine salt) so in the form of sea salt found in Cremonese instruments and the Veneto. It is therefore possible that both Stradivari, as other violin of Cremona makers, as well as the Veneto itself, have been using leftovers Venetian Navy to manufacture their instruments. The question is whether the salt was the fact that only added to further protect the wood against the action of drills termites, or if it is a major factor in the matchless quality of sound and tonal violins quality, especially those designed in the heyday of the master, in the first twenty years of the eighteenth century.
https://youtu.be/qPKKPUm-i54?si=M-lQbr37Fmk1TWQE
Thanks to Saulo Zucchello for above essay 🙏