2. Gut string manufacturing technologies in the eighteenth and nineteenth centuries

Before examining the typical characteristics of eighteenth- and nineteenth-century violin stringing, a topic that squarely falls within the fourth era, it is worth briefly assessing the period preceding the introduction of wound bass strings so as to present the typologies of string available in the late seventeenth century and actually used on this instrument.

Undoubtedly the most comprehensive document on stringing in the period before Bach is the treatise by Thomas Mace. Its most notable aspect — one that had already been mentioned many years earlier by John Dowland (15) — is its division of the strings (in this case for the lute, the most problematic instrument for stringing at that time) into three basic "sorts": strings for the Trebles (Minikins, Romans), strings for the Meanes (Venice-catlins), and strings for Great-basses (Lyons or the "deep dark red" coloured Pistoys) (16).

What this arrangement strongly suggests is not so much a simple commercial distinction or a grouping according to provenance (ever since the early sixteenth century, strings had been named after their respective areas of provenance) as differing types of technology. It seems to imply that diversified manufacturing strategies were followed in order to produce strings that were suited to each register and to ensure a perfect "acoustical" transition between registers. To our experience (as stringmakers) of a working all-gut strung lute the characteristics of each type would appear to be: maximum resistance to wear and breakage for treble strings, maximum elasticity for the strings of the middle register, and an increase in specific weight and elasticity for the bass strings. Finally, though the earliest mention of overspun strings is from England and precedes his treatise, Mace's description of Bass strings still refers to the all-gut strings made exclusively in Italy and France.

An example of seventeenth-century violin stringing is given by James Talbot: "Best strings are Roman 1st & 2nd of Venice catlins: 3rd & 4th best be finest & smoothest Lyons, all 4 differ in size" (17). This is corroborated by iconographic evidence showing an obvious difference between the first two strings, which are light yellow, and the third and fourth strings, which are distinctly brown (18).

To our knowledge, the only seventeenth-century author to give an idea of the gauges of violin strings is Mersenne. His indications, though general, are useful: "la chantarelle des dessus est aussi grosse que la quatriesme des luths" (the violin first string is the same size as the fourth string of the lutes) (19). This means a diameter of between 0.70 and 0.80 mm for the violin first string (20).

With the introduction of overspun strings (and with the consequent increase in demand for them, especially from bowed instruments), the techniques of making all-gut bass strings declined rapidly and were forgotten by the new generation of string makers: just by wrapping a thin metal wire around a gut string one got a much larger sound. As a result, the manufacture of these new strings probably passed immediately into the hands of the luthiers, and sometimes into those of the musicians themselves: the winding of a normal gut string with metal wires would have hardly constituted a problem for the more enterprising among them (21).

The early eighteenth century must have witnessed a drastic narrowing of production: by mid-century the treatises and documents are no longef referring to the wide range of gut commodities described in the previous century (22). In its place there arose a uniform system of string manufacturing that remained in use in the following centuries — and to a great extent still applies today.

String manufacturing technique. Though at first glance the procedures for making gut strings in the eighteenth century look remarkably like those in use today, there were substantial differences. And what these differences unquestionably suggest is that the earlier strings (right up to the end of the nineteenth century) were more elastic, and hence better, than those available today.

Fig 1: Christoph Weigel, der saitenmacher, Regensburg 1698

String making (figure 1) in the past required the use of a whole lamb-gut of a length of at least 50 feet (23). After careful cleaning and rinsing in running water for several days, the gut was subjected to a series of treatments to eliminate the non-muscular membranes and fatty substances. This was done by immersing the gut in alkaline solutions of increasing concentration for a few days, after which the undesirable substances were easily removed with the back of a knife or a fragment of cane. The alkaline solution consisted of plant ashes (potash) mixed with water. The diluted concentrations were sufficient to remove the more easily soluble fatty substances, while the highest concentration was left to the end of the treatment, when more aggressive action was needed to remove all the residual unwanted substances. During this stage a small amount of rock-alum could be added; it would have had a shrinking and tanning effect, thus slightly hardening the gut. In short, the alkaline baths ensured that the organic material underwent a combined process of fermentation and soaping to facilitate the detachment of the undesirable parts, while leaving the muscular membrane — the part that interested the string maker—free of extraneous matter and perfectly degreased.

After this treatment guts were carefully selected and grouped together in parallel strips (according to the diameter of the string to be made) and knotted at both ends. The strips were then attached to a special wheel used for twisting the string while the other end was fixed to a peg at the side of a drying frame (figure 1). After sufficient twisting, the free end of the damp string was disconnected from the wheel and tied to a peg at the opposite side of the drying frame and placed under tension.

When the frame was full, it was taken to a special room where the strings were subjected to a process of whitening by sulphurization. This involved burning sulphur in a basin and subjecting the strings, for several days, to the whitening action of the sulphur dioxide fumes.

When this was completed, the strings were further twisted and given a final drying in the open air for just a few hours. The very last stage consisted of polishing the surface of the strings using a grass with abrasive qualities (equisetum or horsetail) soaked in alkaline solution or tempra.

The perfectly polished strings were then rubbed with olive oil, cut from the ends of the frame, wound in circular bundles and put into boxes. Each box could contain from fifteen up to thirty or more strings soaked in olive oil (24).

There are therefore substantial differences between the procedures followed then and now.

The first important difference is that today lamb's gut has often been virtually abandoned and replaced by material from more mature animals.

Secondly, most stringmakers in the eighteenth century, and much of the nineteenth, used whole gut, whereas in modern practice a special machine is used to cut the material into ribbons; this helps to reduce string conicity, a problem that had always affected the production of chanterelles. It is generally thought that cutting into ribbons was first practised by the late eighteenth-century German makers, though in fact it already existed in Italy around the mid sixteenth century: see the second Roman stringmaker’s statute (the document, which I have examined, is dated 1587 and was discovered in 1999 by Marco Pesci of Rome). In other worlds there are statute rules that inflicted heavy fines on string makers — Roman makers in this case — who were caught splitting gut into halves ("spaccare le mazze, o budelle per mezzo") (25). Evidently, despite the advantage of obtaining more regular gauges, the most powerful corporation of string makers (that of Rome) did not consider it a good practice.

Another difference is that today the fatty substances are removed by using pure sodium carbonate instead of potash, which is an impure potassium carbonate obtained by burning vinasse and wine dregs. And for the whitening process, string makers today use oxidizing agents such as hydrogen peroxide or sodium peroxide.

The last substantial difference from past practice is that the dried rough strings are no longer lightly smoothed with abrasive grass (or pumice powder), but rectified by a special machine (uncenterless machine) capable of producing the wide variety of diameters in demand today.

While at first glance it might seem that modernization merely introduced a few welcome improvements after centuries of unchanged string making technology, this is not entirely correct. Certain seemingly insignificant steps in the earlier process have been unduly overlooked. This is quite evident if we compare modern strings with the few surviving samples of old strings (even relatively recent strings dating from the beginning of this century). The former are often stiff, hard and only lightly twisted; the latter are pliable, soft and highly twisted. In addition, modern strings have, normally, a very short string life unless they are varnished.

The difference in string life is easily explained. Strings made of whole guts and lightly polished by means of abrasive grass or pumice have much fewer broken fibers on their surface than those made from split guts and brought to the desired diameter by mechanical rectification that forcibly removes significant quantities of material from the string's surface.

The second important aspect to have a serious effect on the string's acoustical performance is the sacrifice of elasticity in favour of strength of tension. This almost suggests that today's strings are built to stand up to a tug-of-war and not to provide as good a sound as possible. Instead, to play well, a string must have the capacity to transform the mechanical impulse transmitted by the bow or the fingers into a vibrational movement that is, as far as possible, devoid of the internal frictions that would reduce the efficiency of that transformation.

A number of factors lie behind this "abandonment" of the manufacturers' quest for maximum elasticity. One is that string makers no longer use the gut of young animals, which tends to be less rigid and nervy. Another is the replacement of potash — also known as oil of tartar and widely used until the beginning of this century as a skin softener for the hands — by sodium carbonate, which seems not to have those properties (26). The importance of potash on string quality is confirmed in Pierre Jauber's Dictionnaire raisonné (though we should note that the eighteenth-century Italian string makers produced it by calcinating wine dregs only, while the French used so-called "sieved" ash with its much lower potash content):

On pense qu'y a encore une légere opération a faire aux cordes avant de les exposer en vente; elle consiste vraisem-blablement à les frotter d'huile pour les adoucir et les rendre encore plus souples: mais les boyaudiers en font un mystère; ils assurent qu'ils ne se servent point d'huile, et que c'est dans cette derniere manoeuvre que consiste tout le secret de leur art.

Le boyaudiers ont raison d'assurer qu'ils ne se servent point d'huile pour assouplir et donner du son a leurs corde, mais ils y emploient des sels qui sont extraits de la lie de vin (27).

(It is thought that there is still a light operation to be done on the strings before exposing them to the wind: it seems to consist in rubbing them with oil to soften them and make them even more pliable. But the gut-makers make a mystery of it. They assure you that they make no use of oil and that it is in this last operation that the whole secret of their art lies.

The gut-makers are right to assure us that they do not use oil to soften and give sound to their strings, but for that they use salts extracted from wine dregs).

As general rule, modern strings are often less twisted than the strings of the past. This is shown not only by the historical documents, but also by the examination of several surviving samples of old gut strings (28). It goes without saying that the degree of twist is fundamental in determining the elasticity of a gut string (29).

Old strings were made, in most of cases, with a high twist, with the exception of lute-chanterelles, the strings subjected to the severest working conditions.

We also note that the softening effect of "oil of tartar" on gut permits a much higher degree of twist than the highest level obtainable using modern techniques.

More research needs to be done before we have a better understanding of why the old string makers took several days (up to eight) (30) o conclude the whitening process.In fact, it is only recently that researchers have started to grasp — as the ancient string makers had long been empirically aware — that there was something more to this laborious and awkward process than a matter of whitening the string, an operation that might even seem superfluous (Galeazzi actually disapproved of excessively white strings) (31). What was really involved was the formation of sulfide links between the long chains of collagen, the main constituent of gut, in order to increase elasticity at the expense of plasticity. In short it amounted to a genuine process of "vulcanization", rather like the transformation of an iron wire into a musical steel string.

On this matter Griselini includes a very revealing remark: "Ma l'operazione da noi descritta non basta a dare alla corda 1'elasticità convenevole, ed a renderla sonora. Havvi, per quanto dicesi, un altro segreto ancora, [...] affinchè si secchino lentamente ai vapori del zolfo, ed elastiche divengano" (But the operation we have just described is not sufficient to give the string the right elasticity and to give it its sound. There is, it is said, also another secret [...] for drying them slowly in sulphur vapour, and making them become elastic) (32). Labarraque reiterates the same concept: "L'azione del vapore del solfo e indispensabile per ottenere buone corde musicali" (The action of the sulphur vapour is indispensible for obtaining good strings) (33). As does the great nineteenth-century French string maker Philippe Savaresse: "Le soufrage influe aussi beaucoup sur la qualité des cordes. II est indispensable pour les obtenir bonnes" (Sulphuring has a very strong influence on the quality of the strings. It is indispensible for making them good) (34).

Believing — erroneously, as we have just seen — that sulphurization was merely a process for whitening the gut, twentieth-century string makers decided to carry out the same operation using more convenient chemical solutions. Often, however, especially if used either inexpertly or to excess, these chemical agents can weaken the material and lower the strings resistance to breakage under tension.

Finally, even the function of olive oil seems to be more important than previously thought. Hitherto it has been seen as fulfilling a simple aesthetic function after the polishing process. This would be reasonable enough if it was just a matter of giving the strings a light oiling before packaging. But in the Italian tradition the strings were literally soaked in oil in impermeable packages for a considerable length of time — probably months, if we consider that strings that were too fresh were generally never used on instruments. The careful observer will note that gut strings given a long soaking in olive oil acquire a special consistency as if they had undergone a tanning treatment (very like the fat- or oil-tanning carried out since time immemorial on skins and leather to make them last longer). In fact, treating a gut string in this way increases its life. This also seems to be the function of the rock-alum added to the alkaline solution before the twisting phase (35).

The logical conclusion would appear to be that the strings made in the past were probably, in most cases, superior from the points of view of acoustical performance and durability. Those made today, on the other hand, can boast precise dimensions and therefore rarely sound untrue, which was the constant problem of strings made before the introduction of mechanical rectification.