Raimund Mair

The pumping stations of the historical Augsburg drinking water supply

Raimund Mair Universität Innsbruck, Austria

Introduction – Augsburg and the water

Augsburg, the capital of Swabia in southern Germany, is known today for two periods in its developmental history: as a Renaissance trading city with protagonists such as the patrician families Fugger and Welser, it was in an economic and cultural sense the gateway of Germany to Italy on the axis to Venice. The second phase began with the rise of Augsburg to become a pre- and early industrial production metropolis. Even though the textile industry that dominated at that time has largely disappeared from the cityscape, the high-tech sector continues to exist today with companies such as M.A.N. and KUKA.

Augsburg's abundance of water was decisive for both phases of development. Rich deposits of works and drinking water enabled the emergence of a historic water management system, which was included in the UNESCO World Heritage List in July 2019. What is unique is that this heritage is documented not only in buildings, books and plans, but also in an extensive collection of architectural and technical models dating back to 1620. This collection - the municipal model chamber - was originally stored in the attic of the town hall and is now housed in the Maximilian Museum.

Already in Roman times, the strategically favourable location on an elevated glacial gravel bed at the fork of the Lech and Wertach rivers had offered itself as a suitable location for a fortified Roman camp at the intersection of the Via Claudia Augusta and Via Imperii trunk roads. The fact that this legionary camp was able to grow into the provincial capital of Aelia Augusta (the Latin name Augusta Vindelicorum, which is in common use today, dates back to the sixteenth century) was mainly due to its large supply of drinking water. The area around the high terrace, where Augsburg's old town is located today, is rich in springs and streams fed by them. In addition, abundant groundwater resources at a depth of 10-13 metres made it possible to create draw and pump wells.

What had been sufficiently comfortable according to the standards of a Roman legionary in the provinces, however, no longer met the requirements of hygiene and comfort with the growing population density at the end of the Middle Ages. Since Augsburg did not have a controlled sewage disposal system, what was to be permanently buried underground through the cesspits inevitably came into contact with the drinking water being pumped. Since rainwater cisterns were not a permanent solution either, it was necessary to channel spring water to the high terrace. Gradient water pipes such as those in Goslar (before 1250), Basel (before 1265) and Freiburg im Breisgau (before 1318) were out of the question due to the lack of elevation of the surrounding area. The only viable route was therefore via water pumps.

261 The pumping stations of the historical Augsburg drinking water supply

Augsburg's first fountain - flop or prototype?

“Leopold Karg zu erst das Wasser hat geleitet, daß es durch Röhren sich in der Stadt ausbreitet.” (“Leopold Karg first directed the water to spread through pipes in the city.”)

There is no other sentence that one encounters more frequently when studying the chronicles of Augsburg's drinking water supply. Its creator, the teacher and poet Narciss Rauner (1631-1714), based this statement on information that has been handed down. In the meantime we know that this was not quite true - Leopold Karg was certainly not the designer of Augsburg's first well, but would nowadays rather be called its venture capitalist [1]. And just as in our time, there was no guarantee for the success of a business model back then [2]. It is not documented how Karg wanted to refinance his investment, as the waterworks only supplied public wells. What is known, however, is that the project drove him to ruin and, in order not to become completely impoverished, he was given the office of customs officer at one of the city gates [3]. There is no doubt that this is the case at the traditional location “am Schwibbogentor” (at the Schwibbogen gate, demolished in 1867) on the south-western edge of the upper town, even though it can no longer be reconstructed with exact addresses. The fact that at this point, with the Brunnenbach and the Kaufbach, a drinking water and a motive water pipeline crossed the moat underpins the plausibility of this statement - Augsburg had been concerned from the very beginning with the separation of flowing waters of different purity. And also the year of construction mentioned in most historical sources, 1412, is at least very close to the truth:

As important as the beginning of the drinking water supply on the high terrace was estimated to be in later centuries, little importance was attached to its documentation at the beginning of the 15th century. What is known to us today is certainly based on the Baumeisterbücher (master builder's books) of Augsburg, preserved (with minor gaps) for the period from 1320 to 1789 - the account books of the municipal construction work, a fund of 26 metres of shelf space in length which has only been partially processed. Although there are no records for the year 1412, work on a prunnen Huislin - a small well house - was already accounted for in 1413 [4]. In the same year there is also the first evidence of the underground laying of Deicheln (wooden water pipes). Finally, in 1414, a letter from the Augsburg council to the nearby town of Ingolstadt reported difficulties in settling accounts with the foreman Seitz Hormacher [5]. Other sources call him Hormeister - an indication that this name is rather a job title. He was probably a locksmith specialised in the manufacturing of church tower clocks and produced the mechanical components of Augsburg's first pumping station.

Unfortunately, the chroniclers remain silent about the nature of this. In the books of accounts from 1413, work on a wheel is also mentioned - so the drive must have been done by a water wheel, as in the following centuries. However, the lifting technology itself can at best only be reconstructed by accounting for the materials used: the fact that ropes were procured in addition to grease and pipes gives rise to the suspicion that in the early days, the technology of a pumping station known from mining was used [6]. The mention of “spoons” also supports this - but whether a bucket chain (Fig. 1) or a cascade of bucket wheels was used here cannot be said with certainty. In any case, this early pumping station probably shared one characteristic with its successors: Formulations in connection with an iron delivery suggest that a wooden compensating reservoir was lined or strapped.

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Figure 1. Bucket chain (A. Ramelli, Le Diverse Et Artificiose Machine, Paris 1588)

Why - and also when exactly - this pumping station had to cease service is still unclear. Sources speak of iron pipes that were too narrow and an unsuitable location. Improvements seem to have been worked on, in 1414 the well house was raised - probably to increase the water pressure. However, it would seem obvious that the closure took place shortly after the opening of the next and later largest pumping station in Augsburg, the waterworks at the Red Gate (Rotes Tor).

The waterworks at the Red Gate

The Welser Chronicle of 1595 indicates the construction of a pumping station at the Haußstätter Thor (Haußstätten Gate), the later Red Gate, for the year 1416 [7]. The fountain work at the Schwibbogen Gate is only mentioned in the past tense. But the fact that only four years after the start of the first, unsuccessful pumping station, a first successor was erected at a distance of barely 300 metres raises some obvious questions, especially as the technology used in the fountain works at the Red Gate in the early days is also unknown:

263 The pumping stations of the historical Augsburg drinking water supply

However, if the failure of the first project was actually limited to the traditional points of unfavourable site selection and excessively narrowly dimensioned line pipes, the technical concept in principle could well have proven itself. In this case it would be conceivable that the waterworks at the Red Gate was not so much a new construction as a move to a more favourable location a few metres higher up. Taking along and continuing to use the expensive technical equipment, starting with the water wheel, would be not only logical and would also explain why the demolition of the first pumping station was not acknowledged in the chronicles. And it could help to resolve another discrepancy in historiography:

The Welser Chronicle states that the waterworks at the Red Gate were built by Hans Felber in 1416 [8]. According to other sources, however, he did not come to Augsburg until around 1431-1433 [9]. Before that, he had worked as a cannon founder in Ulm in 1424, among other things. This led to the hypothesis that there would have been a longer time interval between the first and second pumping station. It is also conceivable, however, that 1416 was the starting point, that the existing technical equipment was used and that Felber was involved in the renewal of the pumping station a good fifteen years later. The time period would fit in with the usual replacement cycles of the wooden mechanics, which have a limited durability in damp environments. In addition, Felber's experience in metal casting and machining would have given him the necessary expertise to convert to the first piston pumps. The necessary production facilities would have been in Augsburg - as early as 1372, the bell founders there also called themselves cannon founders, and in addition, a drillmaster probably practised his trade as early as the middle of the fourteenth century [10] [11]. This would have created the conditions for casting pump cylinders from bronze or brass and then drilling the inside of the cast blanks to a uniform diameter.

Piston pumps and their drives

Even if the timeframe for the introduction of single-acting piston pumps can only be based on circumstantial evidence and this hypothesis has yet to be substantiated by archival sources, there is of course an initial point in time from which they can be proven beyond doubt to be state of the art. For the waterworks at the Red Gate, 1599 is the year from which the earliest known ground plan today dates. While it only displays the masonry in a rather schematic way, it shows the different pumping stations as easily understandable diagrams of both their construction and the number of their cylinders.

The fact that a plan from 1599 has been preserved is probably no coincidence - the waterworks had just reached a new stage of expansion. With the further development of the pumping mechanisms and a constant expansion of the pipeline network - since 1558 it had also been possible for (correspondingly well-heeled) private individuals to purchase a connection - the associated water towers had been continuously renewed and increased in height. The first one was a small wooden tower on the foundations of an old fortification tower at the Red Gate. After it burned down in 1464, it was replaced by a first brick five-storey tower, still considerably lower than the neighbouring town gate itself. By adding storeys, its height gradually increased from initially about 20 metres to about 30 metres. As early as 1470, it mutated from a water tower to the Large Water Tower (Großer Wasserturm) (Fig. 2 A), when it was joined by a neighbour - the Small Water Tower (Kleiner Wasserturm) (Fig. 2 B) - as an extension. This too was raised by two floors in 1559 and by one in 1672. Finally, in 1599, the so-called Kastenturm (Box Tower) (Fig. 2 C) was built a few metres away on the same site by rebuilding and adding two storeys to an old fortified tower. On the plan mentioned above it was only hinted at, but its associated pumping station is already included.

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Figure 2. Waterworks at the Reg Gate (C. Walter, Anweisung vor einen jederweiligen Stadt-Brunnen-Meister des Heil. Röm. Reichs-Stadt Augspurg, Augsburg 1766. Tab. 3)

Apart from a small water scoop whose purpose was to pump drinking water into the sump of the Box Tower, the 1599 diagrams show only two types of pumping stations: crankshaft pumps and rack-and-pinion pumps. (Fig. 3) Both were used in parallel in Augsburg for centuries and both had their advantages and disadvantages:

Figure 3. Diagram of the waterworks at the Red Gate by Elias Holl, exhibited in the Large Water Tower. Photo: Author.

Crankshaft pumps (Fig. 4) ran evenly and pumped the water more consistently the more cylinders they had - at the end of the seventeenth century copies with up to five cylinders were already in use in Augsburg's largest water towers. However, their construction was expensive because of the heavy crankshaft, which was complicated to 265 The pumping stations of the historical Augsburg drinking water supply forge - Caspar Walter (1701-69), the master fountain engineer responsible for operating the waterworks, states their mass at up to 1340 pounds, or around 650 kilograms, in the Hydraulica Augustana of 1754, a detailed description of the waterworks at the Red Gate [12]. In addition, the large number of swivel bearings naturally caused considerable friction losses - the push rods of the pistons were connected to the crankshaft via bearings made of apple wood.

Figure 4. Crankshaft pump (C. Walter, Architectura Hydraulica, Oder: Anleitung zu denen Brunnenkünsten Vol. 1, Augsburg 1765. Tab. 12)

The second system consisted of rack-and-pinion pumps (Fig. 5), in which two counter-rotating pistons were always connected by a chain via a disk wheel. Due to their design, they always had an even number of cylinders - usually four. They were less expensive than crankshaft pumps and at first glance appeared to be an impressively simple and elegant design with significantly fewer rotating components. The fact that they were nevertheless used as sparingly as possible, and over time were only kept in stock as reserve pumping stations for maintenance purposes, was due to a problematic design feature: with each rotation of the shaft tree, the gear segments mounted on it had to engage in the racks that actuated the pump pistons. Apart from the necessary accuracy of fit, which

266 Raimund Mair could only be achieved to a limited extent with wooden components, this meant that the uninterrupted, alternating acceleration of the piston rods in opposite directions did not occur in a sliding manner, as in the case of drive by a crankshaft, but was associated with the collision of components each time. Caspar Walter described the resulting vibrations in connection with the construction of a new crankshaft pump:

“Dieses Werck ist erst Anno 1744 zu Conservierung des schwachen Thurn-Gemäurs ganz neu angelegt, und an statt des vormahls allda gestandenen Ketten-Druck-Wercks, so durch sein hartes und starckes Erpumpen und Erschüttern dem Gemäuer successive zimmlichen Schaden zugefüget, so daß schon vor Jahren dasselbe mit einem großen Streb-Pfeiler versorgt werden müssen, erbauet worden.” [13]

(“This work was only rebuilt in 1744 to preserve the weak tower masonry in place of the chain pumping station that had previously stood here, which, due to its hard and strong pumping and vibrations, caused considerable damage to the building over time, so that it had to be secured with a buttress.”)

Figure 5. Rack-and-pinion pump (L. Voch, Einleitung zu der Architectura Hydraulica, Augsburg 1769. Tab. 4)

267 The pumping stations of the historical Augsburg drinking water supply

Models in the water towers

The waterworks at the Red Gate was not only the most important facility of Augsburg's drinking water supply and the seat of the responsible well master, but also the second place, besides the attic of the town hall, for the collection and exhibition of models. Here, mainly models of technical facilities - pumping stations, weirs, sluices, bridges, cranes, pile drivers, drilling machines and mills were shown, i.e. primarily models related to hydraulic engineering. Most of them had no representative or museum character, but served as illustrative material for apprentices, craftsmen and interested visitors. Many of these models have been preserved and are now exhibited in the Maximilian Museum in Augsburg. They were also listed in Caspar Walter's Hydraulica Augustana and in some cases so meticulously described that today it is often easy to clearly assign them to existing exhibits [14].

Unfortunately, the only model of a rack-and-pinion pump has not survived the times and can only be seen in a photograph from the attic of the town hall. A comparison of the inventory lists of the pre-war and post-war periods suggests that it was destroyed during the removal of the exhibits during the Second World War. Models of crankshaft pumps with two, three, four and five cylinders, which, according to Walter, served as illustrative models for design faults, also appear to have been disposed of - here the suspicion is that they were no longer considered sufficiently presentable when they were moved to the town hall attic in the nineteenth century. The evidence of everyday technology was probably considered rather banal, whereas particularly representative or even experimental pumping stations were considered worthy of preservation.

Further waterworks in Augsburg

The fountain works at the Red Gate were the largest and most important, but not the only waterworks in Augsburg. The line pressure achievable with the technology of the time would not have been sufficient to supply the entire city area - and if it had been, the wooden line pipes would probably have been overloaded with it.

In 1754, Caspar Walter counted a total of nine water towers (three at the Red Gate, the remaining plants each had only one) with 18 pumping stations: The Lower Fountain Tower at the Mauerberg (Unterer Brunnenturm am Mauerberg), the two Jakober Fountain Works, which were set up in 1609 by Elias Holl, the builder of the Augsburg City Hall, to supply the Jakober Suburb, and the Fountain Works at the Vogeltor. Two smaller works played only a minor role in the Stadtaicht, the municipal weights and measures office, and in the Maria Stern convent.

From a technical point of view, Augsburg's second largest waterworks at the Mauerberg played a prominent role several times:

The Lower Well on the Mauerberg

The Milan physician and scholar Gerolamo Cardano (1501-76) helped the northernmost pumping station of the High Terrace, which was built around 1450, to achieve its first supra-regional fame when he described it in his book De Subtilitate as Machina Augustana and also depicted it - a cascade of seven Archimedean screws [15]. (Fig. 6) Unlike today's screw conveyors, these consisted of leather hoses that were spirally wound around wooden drive shafts. The designer of this conveyor system is still no more known as the dates of its construction and its end. It is possible that the well was already converted to piston pumps when the water tower was first raised in

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1537, and that crankshaft pumps were used at the latest when the tower was raised to twice its height in 1684. The fact that an inventory of the model chamber from 1838 still lists models of Wasserschnecken (screw conveyors) is not necessarily related to the Machina Augustana - contemporary books on hydraulic engineering often show them as small, manually operated pumping units, for example for the drainage of construction pits [16]. There they could also play out their actual advantage, which is still used today in sewage treatment plants, of being able to lift even heavily contaminated liquids.

Figure 6. Pumping station made of Archemedean screws in the Lower Well Tower (G.Cardano, De Subtilitate Libri XXI, Lyon 1580. p. 33)

Much better documented is the second phase of the technical pioneering role of the Lower Fountain Works:

The beginning of the iron age

At the end of the Baroque period, technology became increasingly rational - Caspar Walter had replaced the ornate inflow taps of the compensating reservoirs with more functional models during his extensive renovation of the waterworks at the Red Gate, and had banished the famous fountain youth created by Adriaen de Vries in 1602 from his place in the box tower to the courtyard of the fountain. At the turn of the nineteenth century, the change 269 The pumping stations of the historical Augsburg drinking water supply from craftsmanship to engineering gradually took place. While the wooden machines were still constructed by the well workers themselves, most of whom were trained as carpenters, external specialists were needed when switching to iron mechanics - in the case of the Lower Fountain Works, this was the engineer Georg Ritter von Reichenbach (1771-1826).

After he had become famous for his Berchtesgaden-Reichenhall-Rosenheim brine pipeline, built between 1810 and 1817 and operated until the twentieth century, the city of Augsburg commissioned him in 1819 to design new water machines [17]. The pumps he constructed for this purpose each had four cylinders, which were operated in pairs by means of swing beams. Their valves controlled by the working pressure were located in separate valve boxes. (Fig. 7) For the time being, however, from 1821 onwards only the first of three machines - the other two were to be installed at the Red Gate - was used in the Lower Well Tower, where it remained in service until the first turbine in Augsburg's drinking water supply was commissioned in 1865.

Figure 7. Reichenbach machine (Dinglers Polytechnisches Journal Vol. 7, 1822. Tab. 6)

The installation of the two machines intended for the waterworks at the Red Gate was delayed. At first probably because the plant had only been rebuilt in 1817 under well master Georg Haevel and its output had been increased from 64 to 100 cubic metres per hour [18]. In the course of time, however, the reasons for the delay were mainly due to an indecisive magistrate who shrank from the extent of the rebuilding work and derogatory criticism from Reichenbach's jealous adversary Joseph von Baader (1763-1835) [19]. By 1846, however, the wooden pumping stations had become so dilapidated that it was finally decided to use the machines, which had been stored in individual parts for a quarter of a century. The city building officer Franz Joseph Kollmann (1800-94) - at the same time one of the most important chroniclers of Augsburg's historical water management - built a new machine house in the courtyard of the waterworks at the Red Gate, in which the two machines started operation in 1848 and increased the hourly pumping volume to 144 cubic metres [20] [21].

The model of the Reichenbach water machine

A special feature of this exhibit is its not only mechanical but also hydraulic functionality. (Fig. 8) In addition, it also traces the history of its models and thus itself becomes an object of building research. Until December 2019, it was assumed that it had been manufactured in that year because of the number “1844” stamped into a valve box. Then, however, a letter from Franz Joseph Kollmann dated 15 September 1838 was found in the Augsburg City

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Archives, in which he recommended that the magistrate purchase a model of the Reichenbach water machine in the Lower Well Tower, built by master turner Werner, for the price of 75 florins. This information led to the discovery of a description of the Augsburg City Hall from 1838, which already mentioned this model in an inventory of the model chamber as a model of the Lower Well Tower with the Reichenbach water machine [22]. It is unlikely to have been the entire tower, as it would have been somewhat large in the present 1:12 scale. Certainly, however, the immediate surroundings of the machine such as the inlet was included.

Figure 8. Model of the Reichenbach machine in the Maximilian Museum, Augsburg. Photo: Author.

The model preserved today certainly shows - clearly visible on the supports of an inlet channel - one of the machines of the waterworks at the Red Gate, which were operated overshot. But its water wheel has buckets on only one quarter of its circumference, the remaining three quarters are equipped with blades of a wheel with an undershot rim. (Fig. 9) This suggests that the original model was reworked six years after it was built - perhaps to use it as an argumentation aid for putting the two unused models into operation. The “1844” - maybe a reference to the update - could then easily have been the time of the conversion. This could also clear up an old misunderstanding - the Augsburg mechanical engineering historian Wilhelm Ruckdeschel had complained in a publication that this model had repeatedly been described in earlier descriptions as belonging to the Lower Fountain Works. No wonder - although its inlet and water wheel had been changed, the description in the inventory records had not.

271 The pumping stations of the historical Augsburg drinking water supply

Figure 9. Mixture of buckets and blades on the water wheel of the model of the Reichenbach machine. Photo: Author.

The end of the well works

Due to Augsburg's population growth in the second half of the nineteenth century (1849: 32,628 inhabitants, 1871: 51,220, 1880: 61,406), the decentralized water supply reached its limits. In 1879 the waterworks at the Hochablass outside the city were put into operation. The old wells were kept in reserve for the time being - there was too much uncertainty as to whether the turbine drive of the new plant would be able to cope with the winter ice drift of the Lech river. Perhaps the last description of the condition of the old well works can be found in a book on Augsburg's drinking water installations from 1881: the two larger waterworks at the Red Gate and the Lower Well Tower would still have been operational, but the remaining facilities were already desolate [23].

Today the water towers at the Red Gate, the Lower Well Tower and one of the Jacob Fountain Towers are still standing - the other was destroyed in a bombing raid in 1944. Apart from a machine foundation in the machine house of the Lower Waterworks, nothing remains of the old pumping stations. The waterworks at the Hochablass was in operation until 1973 and was fortunate to end up in a time when historical technology was more sympathetic to the people. As a completely restored cultural monument, it is in the best possible condition. (Fig. 10)

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Figure 10. Waterworks at the Hochablass (2016). Photo: Author.

Conclusions

An essential part of Augsburg's historic water management system, which was inscribed on the UNESCO World Heritage List in 2019, was the drinking water supply for the upper city. From the early fifteenth century onwards, a system of pumping stations and up to nine water towers was created, which was replaced by a central waterworks as late as 1879. While these facilities are well documented from the seventeenth century onwards, knowledge about their early period is often based on circumstantial evidence and still requires a great deal of research.

References [1] M. Kluger, 'Augsburgs erstes Wasserwerk am Schwibbogentor' in C. Emmendörffer and C. Trepesch (Eds.), Wasser Kunst Augsburg, Regensburg: Schnell & Steiner, 2018. p. 59. [2] M. Welser, P. Gasser, E. Werlich, Chronica Der Weitberuempten Keyserlichen Freyen vnd deß H. Reichs Statt Augspurg in Schwaben Von derselben altem Vrsprung/ Schöne/ Gelegene/ zierlichen Gebäwen vnnd namhafften gedenckwürdigen Geschichten/ in acht unterschiedliche Capitul (dero Innhalt vor anfang dieser Chronicken/ sampt Abbildung und Deutung gedachter Statt alter Monumenten zufinden), Frankfurt am Main: bey Christ. Egen. Erben. 1595. P. 150. [3] M. Kluger, Augsburgs historische Wasserwirtschaft: Der Weg zum UNESCO-Welterbe, Augsburg: context, 2015. p. 190.

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[4] D. Voigt, 'Die Augsburger Wasserwirtschaft des 14. und 15. Jahrhunderts im Spiegel der Baumeisterbücher der Reichsstadt' in C. Emmendörffer and C. Trepesch, (Eds) Wasser Kunst Augsburg. Regensburg: Schnell & Steiner, 2018. p. 55. [5] Kluger (Note 1). p. 59. [6] ibid., p. 60. [7] Welser, Gasser and Werlich, (Note 2). p. 154. [8] ibid. [9] Kluger, (Note 3), p. 194. [10] F. A. Oldenburg, Die Fabriken von Augsburg und Blicke auf die europäische Industrie und Gewerbe-Ausstellungen, Augsburg: Verlag der Matth. Rieger'schen Buchhandlung, 1850. p. 43. [11] H. A. Pierer (Ed.), Universal-Lexikon der Gegenwart und Vergangenheit oder neuestes encyclopädisches Wörterbuch der Wissenschaften, Künste und Gewerbe. Altenburg: Pierer, 1845. Vol.30, p. 194. [12] C. Walter, Hydraulica Augustana, Augsburg: Abraham Detleffsen, 1754. p. 13. [13] ibid., p. 16. [14] ibid., pp. 22-26, 31-36. [15] G. Cardano, De Subtilitate Libri XXI, Lyon: Bartholomaeus Honoratus, 1580. pp. 33-34. [16] Unknown, Die Beschreibung des Rathhauses der Stadt Augsburg, Augsburg: Lauter’sche Buchdruckerey, 1838. p. 32. [17] F. J. Kollmann, Die Wasserwerke von Augsburg, Augsburg: Verlag der Matth. Rieger’schen Buchhandlung, 1850. p. 141. [18] W. Ruckdeschel, Technische Denkmale in Augsburg: Eine Führung durch die Stadt, Augsburg: Birgit Settele Verlag, 1984. p. 28. [19] W. Ruckdeschel, ‘Modelle künstlicher »Wasser-Machinen«’, Zeitschrift des Historischen Vereins für Schwaben, vol.81, pp. 169-190. Augsburg: Joh. Walch, 1988. p. 172. [20] Kollmann, (Note 17), p. 148. [21] Ruckdeschel, (Note 18), p. 28. [22] Unknown, (Note 16), p. 33. [23] W. Kuby, Die Brunnenwerke und neuen Trinkwasser-Verhältnisse der Stadt Augsburg, Augsburg: Math. Rieger’sche Buchhandlung, 1881. pp. 4-15.

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