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In 1854 Munich hosted the General German Industrial Exhibition, for which the Glaspalast (Glass Palace) was built, modelled on London's famous Crystal Palace of 1851. The catalogue ran to almost seven thousand entries, and in its supplements, among the exhibitors from the Free City of Hamburg, a short line appeared: "6782 Deutschbein, R. Hamburg. — Aneroidbarometer" ("6782. Deutschbein, R., Hamburg. — Aneroid barometer"). The jury gave the Hamburg mechanic a single sentence and used it to note the essential point: his two aneroids were offered "zu dem sehr mäßigen Preise von 18 fl." ("at the very moderate price of 18 gulden"). In France, Lucien Vidie's patent was still in force, and a barometer without mercury remained a rarity in Germany.
Nearly twenty years later the same master was producing a barometer that had neither a pointer nor a dial. The movement of its vacuum box was read through a microscope on a photographic scale three millimetres long. Between these two instruments lies the story of a workshop that contemporaries called a "bekannte Barometerfabrik" ("well-known barometer factory"), and of a man of whom the address books preserved only a single initial.
In every nineteenth-century Hamburg address book the master appears as "R. Deutschbein". The catalogue of the 1876 London exhibition of scientific apparatus, the patent list of the "Deutscher Reichsanzeiger" of 1879 and Gustav Hellmann's "Repertorium der deutschen Meteorologie" (1883) also name him by a single letter. The Repertorium, a survey of all German meteorological literature up to the end of 1881, gives him a short, businesslike entry: "Deutschbein R. … — Mechaniker in Hamburg. Wegen der von ihm gefertigten Aneroidbarometer vgl. Petersen u. F. H. Reitz" ("Deutschbein R. — mechanic in Hamburg. For the aneroid barometers made by him see Petersen and F. H. Reitz").
The master's first name, Robert, survives in the specialist literature. Gerhard Stöhr gives it in his book "Aneroid-Barometer, die robuste Alternative" (2016), both in the chapter on the Reitz–Deutschbein system and in the chapter on the Hamburg firm Stäcker & Olms, whose founder learned precision mechanics from Deutschbein.
Lucien Vidie patented the aneroid in London in 1844, in France a year later and in the United States a year after that. Litigation over the patent dragged on from 1852 to 1858, and the patent itself expired in 1859. None of this affected the Hamburg mechanic. The Free Hanseatic City had no patent law of its own until the imperial act of 25 May 1877, and French and British privileges did not extend to the German states. Aneroids could be made freely in Hamburg without waiting for the term to run out in Paris.
The firm's successor later gave 1853 as its founding year: in the 1886 Hamburg commercial directory the business is listed as "Aneroid-Barometer-Fabrik. Begründet 1853" ("aneroid barometer factory, founded 1853"). The Munich exhibition bears this date out. Only a year after the founding, Deutschbein was showing finished aneroids at an all-German industrial exhibition. This is one of the earliest documentary records of their manufacture in Germany.
The earliest entry found for the master in the Hamburg address books dates from 1855: "Deutschbein, R., Mechaniker, erste Elbstr. 8" ("Deutschbein, R., mechanic, Erste Elbstraße 8"). In 1858 he is listed at Alter Steinweg 58, and in 1860 and 1861 at Hohe Bleichen 14, in Hamburg's Neustadt.
In 1858 several of his barometers were submitted for assessment to the technical section of the Patriotic Society (Patriotische Gesellschaft), the Hamburg society for the promotion of the arts and useful trades founded in 1765. F. Petersen published the report on the tests in the "Zeitschrift des Vereines deutscher Ingenieure". His note "Aneroidbarometer von R. Deutschbein in Hamburg" ("Aneroid barometer by R. Deutschbein in Hamburg") appeared in the journal's third volume, for 1859 (p. 28), with drawings on Plate II (Figs. 9–13). It is the first detailed description of a Deutschbein instrument in print and the only known illustration of his dial mechanism.
Petersen begins: "Es wurden vor Kurzem einige dieser besonders bei der Schifffahrt immer mehr Eingang findenden Barometer der technischen Section der patriotischen Gesellschaft in Hamburg zur Begutachtung vorgelegt" ("Some of these barometers, which are finding ever wider use, especially in shipping, were recently submitted for assessment to the technical section of the Patriotic Society in Hamburg"). The author and several colleagues were asked to compare their accuracy and sensitivity with other good barometers. Observations were repeated "3 bis 4 Mal täglich" ("three or four times a day") over a long period. The verdict was flattering: the Hamburg instruments "mindestens für alle nicht wissenschaftliche Zwecke gute Quecksilberbarometer und dieselben Barometer französischer Construction bei weitem zu ersetzen vermögen" ("are, at least for all non-scientific purposes, fully able to replace good mercury barometers and barometers of the same kind of French construction"). They were also "bedeutend empfindlicher" ("considerably more sensitive") than the French ones and gave a much larger pointer travel on their very large scale.
The committee also judged the workmanship: "Außerdem wurde die Arbeit sehr solide und auch besser als die der französischen gefunden, auch diesen gegenüber manche nach und nach von Herrn D. eingeführte Verbesserungen bemerkt" ("In addition, the workmanship was found to be very sound and even better than that of the French, and, compared with the French instruments, a number of improvements gradually introduced by Mr D. were noted"). The next sentence of the report says more about the man than any address book. The technical section proposed that the master be awarded the society's silver medal "mit Rücksicht auf die außerordentliche Ausdauer, welche Hr. D. trotz aller sich ihm anfangs entgegenstellender Hindernisse bewiesen" ("in view of the extraordinary perseverance that Mr D. has shown in spite of all the obstacles that at first stood in his way"). When the note went to press, the decision on the medal was still pending.
Petersen also described the commercial side: "Hr. D. liefert die Scalen nach Maß und Sprache ganz wie sie von dem Besteller gewünscht werden, und läßt dieselben für Wiederverkäufer mit ihrem Namen anfertigen" ("Mr D. supplies the scales in whatever units and language the customer wishes, and has them made for resellers bearing their own names"). For the outer finish the master offered "eine große Auswahl geschmackvoller Zinkgußwaaren" ("a large selection of tasteful cast-zinc wares"), and his prices were about 25 per cent below those of French barometers.
These lines give a picture of the business in the late 1850s. Deutschbein made the movements himself and matched scales and cases to the customer, including under other people's names. A considerable share of his aneroids very probably went to opticians and dealers who sold them under their own brands. Some stayed in Hamburg, some went to other German lands and some to the neighbouring Danish territories, which included Altona until 1864. Fourteen years later Professor Wilhelm Jordan would complain that German aneroids all too often bore the seller's name instead of the maker's. In 1859 the same practice was presented as a service the master offered.
Petersen's drawings show a mechanism built to Vidie's early design. Two thin tombac plates, A and A′, joined at the edge by a ring, form the vacuum box. The lower plate is fixed to the baseplate B by screw a. The upper plate carries a metal piece b with a pin c, which presses on plate C resting on the supports d and d′. The air pressure is resisted by "die sehr kräftige Spiralfeder e" ("the very strong helical spring e"), which stands beside the box and keeps it from collapsing. From plate C a thin steel rod f transmits the motion to a horseshoe-shaped piece g fixed on the arbor h. As the arbor turns, point i on the extension of piece g moves. A chain attached to it, kept taut by a fine hairspring k, turns the pointer arbor l. Screws x and y serve for fine adjustment.
The design with an external helical spring was not Deutschbein's own. W. E. Knowles Middleton, the historian of the barometer and author of the classic "The History of the Barometer", remarked on this: "It is interesting that a very similar mechanism was described in 1859, the external helical spring being considered to be a new invention made by R. Deutschbein of Hamburg". What belonged to the master was the refinement and certain components. Petersen put the most remarkable of these in a footnote: "Die Kette ersetzt Herr D. bei seinen neusten Instrumenten durch einen von ihm besonders präparirten Seidenfaden, der seine Elasticität verloren, wodurch er den der Kette immer eignen geringen todten Gang gänzlich zu vermeiden behauptet" ("In his newest instruments Mr D. replaces the chain with a silk thread specially prepared by him, which has lost its elasticity, and claims that he thereby entirely avoids the slight backlash always inherent in the chain"). The fight against backlash would run through all his later work.
Figure 13 of the same plate shows the dial. It carries the words "Aneroid Barometer" in Gothic lettering, an inch scale from 28 to 31, and weather words in two languages: "STORM / Sturm", "MUCH RAIN / Viel Regen", "RAIN / Regen", "CHANGE / Veränderlich", "FAIR / Schön", "SET FAIR / Sehr Schön", "VERY DRY / Beständig". The English words point to the market the Hamburg master worked for: according to Petersen, such barometers were spreading above all on ships. In the lower part of the dial a Réaumur thermometer lies across the scale, and the tail of the pointer ends in a crescent-shaped counterweight.
The documents on the 1860s are sparse but telling. In 1868 Georg Schweinfurth set out on his famous journey to the Bahr el Ghazal region, into "the heart of Africa". He carried three aneroids: No. 1 was of Paris make, and Nos. 2 and 3 were "von Deutschbein in Hamburg angefertigt" ("made by Deutschbein in Hamburg"). The test proved harsh. The astronomer W. Schur, who reduced the expedition's height measurements, wrote in 1873 that the Hamburg instruments were noticeably inferior to the Paris one. The third barometer began to show large irregularities while still on the way and was completely unusable by the time the expedition returned. The readings of the second could be used after corrections, which were found when the Berlin aneroid makers Bohne & Wanschaff checked it. Central Africa was a cruel test for any aneroid of the period. The very choice of instruments for the expedition shows that by the end of the 1860s Deutschbein's name was known far beyond Hamburg.
By 1871 the workshop had moved to ABC-Straße 36, near the Gänsemarkt. This would become its principal address. The street directory of 1873 again records the name Deutschbein at No. 36, and in 1881 the master is listed as the owner of the house ("E.", Eigentümer), occupying the ground and third floors.
At the beginning of 1873 Wilhelm Jordan, professor at the Karlsruhe Polytechnic and editor of the "Zeitschrift für Vermessungswesen", opened the journal's second volume with a long article on height measurement with the spring barometer. He gave German manufacture a single sentence: "Die Zahl der Verfertiger von Federbarometern ist bis jetzt noch ziemlich gering, in Deutschland werden solche, soviel uns bekannt ist, nur construirt von Deutschbein und von Gabory in Hamburg" ("The number of makers of spring barometers is still rather small; in Germany, as far as we know, they are constructed only by Deutschbein and by Gabory in Hamburg"). As evidence Jordan cited Petersen's note of 1859. Edm. Gabory was one of Hamburg's oldest optical houses, and the early history of the firm A. Krüss is also linked to it. By Jordan's account, all German aneroid making then fitted into two workshops in a single city.
In the same article Jordan made two remarks that fit well with Petersen's description. The first concerned names: "Es ist zu bedauern, dass man häufig statt des Verfertigers den Verkäufer auf dem Instrument genannt findet" ("It is to be regretted that one often finds the seller rather than the maker named on the instrument"). The second concerned inscriptions. In the professor's view, the custom deserved censure by which instruments "durch sinnlose Inschriften, wie z. B. „Schön Wetter“, „Sturm“ etc. verunstaltet werden" ("are disfigured by meaningless inscriptions such as 'Fair Weather', 'Storm', etc."). Deutschbein's 1859 dial broke this rule in two languages at once.
For his tests Jordan also took an ordinary Hamburg instrument: "Ein Instrument von Deutschbein in Hamburg (Preis nur 20 Gulden = 34 Mark) mit gedruckter Theilung" ("An instrument by Deutschbein in Hamburg (price only 20 gulden = 34 marks) with a printed scale"). A Naudet & Hulot aneroid then cost about 50 marks. In fifteen height measurements the Hamburg instrument consistently gave heights that were too low, from which Jordan concluded that its scale value was slightly too large. It was an inexpensive dial aneroid for everyday use, and it was judged by a geodesist's strict standards.
In May of the same year the World Exhibition opened in Vienna. The official catalogue of the German section lists, in Group XIV, "scientific instruments", the entry "Deutschbein K., Hamburg. Barometer". The initial is a misprint, and the list of awards repeats it. The official German report on the exhibition makes clear what the Hamburg master had brought. It first lists the Viennese makers of good instruments "nach dem System von Vidie mit den Constructionsänderungen von Naudet" ("on Vidie's system with Naudet's constructional modifications"). The author then adds: "ebensolche in Taschenuhrformat waren von Deutschbein in Hamburg, von Lion & Guichard in Paris und von Pillischer … zur Ausstellung gebracht" ("instruments of the same kind in pocket-watch format were exhibited by Deutschbein of Hamburg, by Lion & Guichard of Paris and by Pillischer"). The international jury awarded the Hamburg barometers a Medal of Merit (Verdienstmedaille). The report suggests that by 1873 the master who had started with Vidie's early design had also mastered Naudet's construction with its steel leaf spring, and in a pocket version at that.
In the same year, 1873, the name of the man who would shape the workshop's next fifteen years first appeared in print. F. H. Reitz was a Hamburg civil engineer and surveyor. He later headed a department of the Hamburg Survey Office and directed the height survey of the city's environs. Reitz also designed a self-recording tide gauge ("Neuer Fluthapparat", 1876–1877), and he approached the aneroid as a surveyor. He doubted mechanical means of magnification, "Hebel, Schrauben, Ketten, bezüglich Fäden, mit zugehörigen Achsen und Lagern" ("levers, screws, chains or threads, with their arbors and bearings"), even when they were superbly made. The movement of the box is minute, and it has to be magnified more than a thousand times. "Es schien dem Verfasser die Anwendung optischer Mittel hier geboten" ("It seemed to the author that the use of optical means was called for here"), he wrote later. His list of doubtful parts included the very thread with which Deutschbein had replaced the chain in 1859.
Reitz's short note "Ein neues Federbarometer mit mikroskopischer Ablesung" ("A new spring barometer with microscopic reading") is dated 17 July 1873 and was printed in the second volume of the "Zeitschrift für Vermessungswesen". Instead of a lever train, a scale viewed through a microscope is attached to the spring that balances the box. The scale is divided directly into hundredths of a millimetre: "Man taxirt mit Leichtigkeit Tausendstel Millimeter" ("Thousandths of a millimetre are easily estimated by eye"). One thousandth of a millimetre on the scale corresponds to a height difference of about a quarter of a metre. Such a design has no backlash, and changes in air pressure show in the reading instantly. The road to this goal, Reitz admits, was a long one, "da für einige Requisiten erst besondere Herstellungsweisen erdacht werden mussten. Namentlich bezieht sich dies auf die eigenthümlich fabricirte Scale" ("because special methods of manufacture first had to be devised for some of the parts; this applies above all to the scale, made in a quite peculiar way"). The note ends with the sentence it was largely written for: "Das beschriebene Instrument ist bereits in mehreren Exemplaren von der bekannten Barometerfabrik von R. Deutschbein in Hamburg ausgeführt. Der Preis beträgt 40 Thaler" ("The instrument described has already been made in several examples by the well-known barometer factory of R. Deutschbein in Hamburg. The price is 40 thalers").
Reitz also pointed at once to the meteorological side. Observations taken every five minutes over eight hours showed "die schönsten Wellenlinien" ("the most beautiful wave lines") on the slope of a falling-pressure curve. Jordan explained why the new instrument could do this: it did not have to overcome the inertia of a transmission mechanism.
That same July Deutschbein sent instrument No. 1 to Jordan in Karlsruhe, "vom Verfertiger als Recensionsexemplar gesendet" ("sent by the maker as a review copy"), priced at 120 marks. Jordan compared it with a Naudet aneroid bought in Vienna in 1871 for 73 marks and with a Goldschmid instrument at 112 marks. His description of the view through the eyepiece is precise and vivid. The scale in the microscope looked just like a levelling staff with centimetre divisions seen through a good levelling telescope from about 50 metres away. One division corresponded to roughly 0.2 millimetre of mercury, and tenths were easily estimated by eye. The whole scale covered about 68 millimetres of mercury. Jordan noted that Deutschbein had already made scales covering 100 millimetres and that nothing prevented making them longer. On journeys through the Black Forest the 68-millimetre range proved insufficient, and the professor twice had to reset the scale with its screw.
On 16 September 1873 Deutschbein wrote to Jordan, and the professor's article preserves the only known direct words of the master himself: "Eine auffallende Erscheinung beobachtete ich heute früh mit einem solchen Federbarometer: Wir hatten einen niedrigen Barometerstand 27″ 6‴ und es war etwas windig. Ich hatte von 7 Uhr an jede halbe Stunde notirt, immer eine langsam fallende Bewegung bemerkt. Da nahm ich 9½ das Ding wieder zur Hand, um abzulesen, und sehe ein immerwährendes Auf- und Niederschwanken bis 1½ Balken der Theilung, wohl 10 Minuten währte es so fort, auf einmal hörte es auf und mit ziemlicher Schnelligkeit fing es an zu steigen" ("This morning I observed a striking phenomenon with one of these spring barometers. We had a low barometer reading, 27 inches 6 lines, and it was somewhat windy. From seven o'clock I had noted the reading every half hour and had always seen a slow fall. Then at half past nine I took the thing in hand again to read it, and I see a continual swinging up and down of up to one and a half divisions of the scale; it went on like this for perhaps ten minutes, then all at once it stopped and began to rise fairly quickly"). The editors explained that one and a half divisions corresponded to 0.3 millimetre of mercury. In 1859 the master had battled the backlash of a chain, and he still reckoned pressure in Paris inches and lines out of old habit. Now he saw with his own eyes how the atmosphere breathes.
Jordan's comparison ran for more than a month. He checked the instruments against the mercury barometer of the Karlsruhe meteorological station, on climbs of the Durlacher Warte tower, on a four-day journey through the Black Forest, under the bell jar of an air pump and through sudden changes of temperature. The comparison did not end in the new instrument's favour. The old Naudet aneroid came out best, while the readings of the new instrument slowly drifted. Jordan explained this honestly and without a hasty verdict: "Dass das Naudet-Instrument besser als die beiden anderen erscheint, hat vielleicht mit darin seinen Grund, dass es älter und schon vielfach gebraucht ist, während die beiden anderen neu sind, wenigstens kommt das Deutschbein-Instrument soeben aus der Werkstätte" ("That the Naudet instrument appears better than the other two may be partly because it is older and has already seen much use, whereas the other two are new; at least the Deutschbein instrument has only just come out of the workshop"). He gave the aim of the tests as "die Gewinnung eines Urtheils über die im Princip vorzügliche neue Construction von Deutschbein" ("to arrive at a judgement on Deutschbein's new construction, excellent in principle"). Incidentally, the professor himself called the instrument not Reitz's but "Federbarometer von Deutschbein" ("Deutschbein's spring barometer").
The fullest descriptions of the instrument come from four sources: Paul Schreiber in Dingler's "Polytechnisches Journal" (1875), the American engineer W. W. Evans (1875), Poten's military encyclopaedia (1877) and a note in the "Mittheilungen" of the German and Austrian Alpine Club (1879). The vacuum box acts on a one-armed lever, the end of which is pulled by "eine starke Spiralfeder" ("a strong helical spring"); the lever arms are in the ratio of one to ten. A tiny scale is mounted at the end of the lever. It was made photographically and, according to Evans, reduced 300 times from the original. It is three millimetres long, with each millimetre divided into a hundred parts. The Alpine Club note specifies that the scale is executed "in mikroscopischer Photographie … auf einer kleinen Glasplatte" ("by microscopic photography … on a small glass plate"). A microscope with cross-hairs is fixed opposite the scale. The observer has nothing to set or turn: he reads which line the cross-hairs fall against and estimates tenths of a division by eye.
Since the lever magnifies the movement of the lid tenfold, one division of the scale corresponds to a thousandth of a millimetre of box travel, and estimation by eye gives ten-thousandths. By Jordan's determination, one millimetre of scale corresponded to 22.26 millimetres of mercury. According to the 1876 London catalogue, an estimated tenth of a division corresponded to about 1/30 millimetre of mercury, or a third of a metre in height. For a field aneroid of the 1870s this was an exceptional resolution.
The microscope aneroid grew from the same root as the 1859 mechanism. The box, the lever and the strong helical spring stayed in place. Everything after them disappeared: rod, horseshoe, arbor, chain or thread, hairspring and pointer. The microscope replaced them all. The spring remained a helical one, and critics later more than once held it against the instrument.
Precision came at the cost of range. The three-millimetre scale covered about 68 millimetres of mercury. Schreiber calculated: "Um die Barometerstände von 500 Mm. bis 780 Mm. beobachten zu können, muß die Scale auf 11 Mm. verlängert werden. Deutschbein soll schon Instrumente mit Scalen von 5 Mm. Länge ausgeführt haben" ("To be able to observe barometer readings from 500 mm to 780 mm, the scale would have to be lengthened to 11 mm. Deutschbein is said to have already made instruments with scales 5 mm long"). In practice the scale was reset with a screw when necessary. In an article of 1877 Reitz described a version with an arc scale. A photographic "Kreistheilung" ("circular division") with divisions of twenty seconds of arc allowed readings to two seconds. This corresponded to about 1/30 millimetre of mercury, or three decimetres of height.
The instrument was kept in a small wooden case together with a thermometer and carried on a strap over the shoulder. Only the "station" instrument, which stood in one place all day, was set on a light tripod. In 1882 Reitz gave the price as 120 to 150 marks. The higher price applied when the instrument had a device for resetting the microscope and a small mirror for reading the thermometer.
In 1874 a brochure by Reitz appeared in Hamburg whose title assigned the roles precisely: "Ueber die Ausführung von Höhen-Messungen mit dem Aneroid-Barometer. System Reitz, aus der Fabrik von R. Deutschbein in Hamburg" ("On carrying out height measurements with the aneroid barometer. Reitz system, from the factory of R. Deutschbein in Hamburg"). The system belonged to the engineer, the manufacture to the master.
The first reviews were reserved. Paul Schreiber discussed new aneroid designs in Dingler's journal. He found Jordan's results for the Hamburg instrument "nicht besonders günstig" ("not particularly favourable"), but noted that the Naudet instrument had long been in use while the Deutschbein instrument had only just left the factory. Schreiber concluded that the exceptionally convenient Naudet aneroids were at least as good for practical levelling, "dagegen dürfte das System Reitz wohl bei Variationsbeobachtungen vorzuziehen sein" ("whereas for observations of pressure variations the Reitz system should probably be preferred").
Meanwhile the instrument crossed the ocean. In February 1875 the American railway engineer W. W. Evans, who built railways in Peru and Chile, wrote in "The Railroad Gazette": "Having heard of a recent improvement in the aneroid barometer, for differential purposes, through a German engineer now travelling in this country, I sent for one, and now have it before me. It is designed by F. H. Reitz, civil engineer, of Hamburg, and made by R. Deutschbein in Hamburg, and is said to give very good results". Having described the photographic scale and the microscope, Evans concluded: "This arrangement appears to be far in advance of anything preceding it connected with the aneroid".
In 1876 the workshop took part in the London exhibition of scientific apparatus at South Kensington, the Special Loan Collection of Scientific Apparatus. In the third edition of the catalogue (1877) Deutschbein is represented by three pairs of instruments: "2817. Two Aneroid Barometers, exhibitor's construction, with visible movement", "2818. Two Metal Barometers, exhibitor's construction, with visible movement" and "2819. Two Spring Barometers, exhibitor's construction, with visible movement". In the 1876 edition, pairs 2817 and 2819 were still listed as "Reitz system". The three different names (aneroid, metal and spring barometer) and the note "exhibitor's construction" against each pair show a workshop that by the mid-1870s ran several lines of its own at once. The catalogue's explanatory note distinguishes their purposes: "The first four are house barometers, distinguished by good workmanship, shape, and cheapness. The last two instruments are spring barometers, specially adapted to meteorological observations, determination of heights, &c." A description of the Reitz system follows, ending with the words: "Its construction is considerably simpler than usual; optical means serve to magnify the movements of the vacuum box, instead of the customary transmission by lever; the instrument is easily handled in the field". The Hamburg Bau-Deputation (building department) also exhibited the 1874 brochure in London, together with material from its survey office.
In the official German report on the exhibition, the section on meteorological instruments was written by Georg Neumayer, director of the Deutsche Seewarte in Hamburg, and Paul Schreiber. They named "Deutschbein (Reitz' System) in Hamburg" among "die vorzüglichsten Aussteller" ("the most excellent exhibitors") of aneroids, alongside Negretti & Zambra, Casella, Pastorelli, Redier, and . Reitz's instruments, the authors wrote, "sich ganz besonders bei Nivellementsaufnahmen mit geringen Höhendifferenzen einer grossen Beliebtheit erfreuen" ("enjoy great popularity, especially in levelling surveys with small differences of height"). Max Borns also singled out the aneroids "von Goldschmid in Zürich und Deutschbein in Hamburg" ("by Goldschmid in Zurich and Deutschbein in Hamburg") in his review of the same exhibition for the popular journal "Die Natur".
The year 1877 brought several assessments at once. Bernhard von Poten's military encyclopaedia wrote: "Eine der bedeutendsten Fabriken von A[neroiden] in Deutschland ist die von R. Deutschbein in Hamburg, aus der das besonders einfache und genau arbeitende Federbarometer von Reitz … hervorgegangen" ("One of the most important aneroid factories in Germany is that of R. Deutschbein in Hamburg, from which the particularly simple and accurate spring barometer of Reitz has come"). The geodesist Christian August Vogler was more categorical and more critical: "Der einzige deutsche Verfertiger von Aneroiden, Deutschbein in Hamburg, stellte Barometer nach Reitz'schem System aus, deren Construction jedoch, um den Forderungen des Bergsteigers zu genügen, noch der Verbesserung bedürftig ist" ("The only German maker of aneroids, Deutschbein in Hamburg, exhibited barometers of the Reitz system, whose construction, however, still needs improvement to satisfy the requirements of the mountaineer"). The geologist Alfred Jentzsch, reporting on his survey work in East Prussia, mentioned in passing that he had used "einem vorzüglichen Aneroid von Deutschbein in Hamburg" ("an excellent aneroid by Deutschbein in Hamburg").
The highest praise came from Schreiber in his "Handbuch der barometrischen Höhenmessungen" (Weimar, 1877). He pointed to a drawback: the correction changes whenever the microscope is set differently, so a fixed reference mark is needed, as on Weilenmann's instrument. Yet he concluded: "Auf Schiffen und an meteorologischen Stationen, in Basisstationen bei Aufnahmen der Ingenieure sollte aber stets das System Reitz zur Anwendung kommen. Es wird dann wohl das bequemste und zuverlässigste Instrument sein" ("On ships, however, at meteorological stations and at base stations in engineering surveys, the Reitz system should always be used. It will then probably be the most convenient and reliable instrument").
On 14 October 1878 the Hamburg Section of the German and Austrian Alpine Club held a meeting. There Obergeometer H. Stück, author of tables for height surveying published in 1873, showed the new aneroids used to survey the environs of Hamburg. According to the section's report, "Herr Stück ist bemüht diese die genauesten Resultate gebenden Instrumente in kleinerer und handlicherer Form durch den hiesigen Mechaniker Herrn Deutschbein herstellen zu lassen, um sie auch für alpine Zwecke gebrauchbar zu machen" ("Mr Stück is endeavouring to have these instruments, which give the most accurate results, made in a smaller and handier form by the local mechanic Mr Deutschbein, so as to make them usable for Alpine purposes as well").
The June 1879 issue of the club's "Mittheilungen" already reported "dass der Federbarometer-Fabrikant Deutschbein in Hamburg nunmehr das Reitz'sche Federbarometer auch in kleineren Dimensionen anfertigt" ("that the spring-barometer manufacturer Deutschbein in Hamburg now also makes the Reitz spring barometer in smaller dimensions"). The new instrument fitted into a small wooden case measuring 77 by 64 by 37 millimetres, weighed little and could easily be carried in a pocket. The author of the note stressed that it could be read without any setting at all, whereas with dial aneroids "der Parallaxe wegen Manches zu wünschen übrig bleibt" ("much is left to be desired because of parallax"). He recommended the compact instrument not only to tourists but also for scientific observation.
On 29 July 1879 the "Deutscher Reichsanzeiger" printed this entry in its list of patent applications: "Nr. 21565. R. Deutschbein und F. H. Reitz in Hamburg, A. B. C. Str. Nr. 36. Reise-Aneroid mit mikroskopischer Ablesung. Kl. 42" ("No. 21565. R. Deutschbein and F. H. Reitz in Hamburg, ABC-Straße 36. Travelling aneroid with microscopic reading. Class 42"). This is the only document in which the master and the engineer appear as co-applicants, and their shared address is the house of Deutschbein's workshop. The title speaks for itself: the application very probably covered the travelling version that was already in production by the summer of 1879. Under the 1877 law, a published application gave the invention temporary protection against unauthorised use.
This application apparently never became a patent. The only patent granted for the system, DRP 9779, went to Reitz alone and ran from 13 December 1879: "Mikrometervorrichtung mit beweglichem Gewicht für das Reitz'sche Aneroidbarometer und für andere geodätische Instrumente" ("micrometer device with a movable weight for the Reitz aneroid barometer and for other geodetic instruments"). The patent specification restates the main principle: the pressure is read "an einer Scala, welche sich mit der luftleeren Dose in Verbindung bewegt, mittelst eines festen Mikroskops" ("on a scale that moves together with the vacuum box, by means of a fixed microscope"). The novelty was a small movable weight. Shifting it with a rod put a little more load on the helical spring. This let the observer bring the nearest line of the main scale to the cross-hairs and read the size of the shift on a separate weight scale. In the patent's example the reading is made up of 750 millimetres on the main scale and 4.7 on the weight scale: "Der Barometerstand wäre demnach 754,7 mm" ("The barometer reading would accordingly be 754.7 mm").
Leopold Loewenherz edited the report on scientific instruments at the Berlin Industrial Exhibition of 1879, and it summed up the system's first years. The most widespread aneroids, Naudet's, were already, "wie es scheint" ("as it seems"), meeting successful competition from the metal barometers "von Goldschmid und Weilenmann in Zürich, Deutschbein und Reitz in Hamburg" ("of Goldschmid and Weilenmann in Zurich, Deutschbein and Reitz in Hamburg"). The same report briefly describes the construction. A lever connected to the lid of the box carries "eine kleine, auf photographischem Wege hergestellte Skale" ("a small scale produced by photographic means"), which is read with a fixed microscope.
The workshop on ABC-Straße was also a school. According to Stöhr, Johann Ludwig Nicolaus Stäcker (b. 1857) learned precision mechanics from Robert Deutschbein. In 1881 Stäcker passed his master's examination with an aneroid mechanism of his own design as his examination piece. In 1882 he and a partner founded the firm Stäcker & Olms, which was still in business in the 1980s. Given his year of birth, Stäcker must have trained in the 1870s, the very years when the microscope aneroid was taking shape on ABC-Straße.
In 1882 Reitz himself described the Hamburg experience. The surveyor Helferich quoted his communication in a lecture on aneroid height surveying: "Die hier verwandten Aneroide (System Reitz) wurden von dem Barometerfabrikanten Deutschbein hierselbst A. B. C.-Strasse Nr. 36 geliefert" ("The aneroids used here (Reitz system) were supplied by the barometer manufacturer Deutschbein of this city, ABC-Straße No. 36"). By Reitz's estimate, the mean error of each height was about half a metre, and one surveyor could cover one and a half square miles a day. These measurements were the basis for maps of the environs of Hamburg with contour lines at one-metre intervals. In the same year the Technische Hochschule Braunschweig exhibited aneroids at the 11th general meeting of the German Geometers' Association (Deutscher Geometerverein) in Hanover. Alongside instruments by Naudet, Goldschmid and Bohne, it showed an "Aneroidbarometer nach Reitz, Fabrikant Deutschbein in Hamburg" ("aneroid barometer after Reitz, maker Deutschbein in Hamburg").
In 1883 Hellmann summed up German meteorology up to the end of 1881. In his subject index, under "Aneroid", he placed a heading "Deutsche Konstrukteure" ("German designers") with just two names: "Bohne, O. Deutschbein". The "Handbuch der Ingenieurwissenschaften" of the same year reported that Reitz instruments were made by "Mechaniker Deutschbein in Hamburg" ("the mechanic Deutschbein in Hamburg") at a price of 120 marks.
Serial numbers make it possible to gauge the scale of production. Instrument No. 1 went to Jordan in July 1873. Instrument No. 39, bought in 1883, was examined by C. Reinhertz at Poppelsdorf near Bonn. Instrument No. 40 was acquired in December 1884 for 160 marks by the geodetic collection of the Stuttgart Polytechnic. Some forty microscope aneroids in eleven years means individual craftsmanship, not factory series production. Professor Ernst Hammer tested No. 40 in the summer of 1886. He called it "ohne Zweifel eines der vollkommensten der aus der Deutschbein'schen Werkstätte hervorgegangenen Reitz'schen Aneroide" ("without doubt one of the most perfect Reitz aneroids to have come out of Deutschbein's workshop") and noted that it was the first example with a secure mounting for the microscope.
Hammer's results were published in 1887 in two journals at once. Over short sections of up to 600 metres with height differences of up to 80 metres, the instrument gave interpolated heights with a mean error of 0.4 metre. "Diese Genauigkeit ist immerhin mindestens doppelt so gross, als sie mit Quecksilberbarometern, sowie mit Naudet'schen und Goldschmid'schen Aneroiden zu erreichen ist" ("This accuracy is at any rate at least twice as great as can be attained with mercury barometers, and with Naudet and Goldschmid aneroids"). In the "Zeitschrift für Instrumentenkunde" the conclusion was even more direct. For small differences of height, "das benutzte Deutschbein'sche Instrument anderen Aneroiden bedeutend überlegen ist" ("the Deutschbein instrument used is considerably superior to other aneroids"). Reitz's idea itself, a simple, moderate transmission with the reading refined by purely optical means, was a real step forward. Hammer did not forget the old complaint either: "Auch die mehrfach beanstandete Spiralfeder der Reitz-Deutschbein'schen Aneroide scheint der vorzüglichen Brauchbarkeit dieser Instrumente für gewisse Zwecke nicht nothwendig Eintrag zu thun" ("Even the much-criticised helical spring of the Reitz–Deutschbein aneroids does not seem necessarily to detract from the excellent usefulness of these instruments for certain purposes"). Fourteen years after instrument No. 1's unhappy debut, Reitz's idea had, in Hammer's words, received "volle Bestätigung" ("full confirmation").
As late as December 1884, instrument No. 40 came "aus der Deutschbein'schen Werkstätte" ("from Deutschbein's workshop"). By 1886 the factory had a new owner. The commercial directory of Hamburg, Altona and Ottensen for that year has a section "Meteorologische Instrumente und Waaren. Fabrik und Handlung" ("meteorological instruments and goods; manufacture and trade"). It contains the entry "J. Bornholdt, vorm. R. Deutschbein, ABC-Strasse 36, Aneroid-Barometer-Fabrik. Begründet 1853" ("J. Bornholdt, formerly R. Deutschbein, ABC-Straße 36, aneroid barometer factory, founded 1853"). Edm. Gabory at Adolphsplatz 3 appears on the same page. Thirteen years after Jordan's article, the two firms he had named as the only German aneroid makers stood side by side in the directory. A supplement to the same book lists changes of address and records a move: "J. Bornholdt, R. Deutschbein Nachf." ("J. Bornholdt, successor to R. Deutschbein") was now at Poolstraße 41, formerly ABC-Straße 36.
By 1890 the firm had moved to Hopfensack 6 and widened its business: "J. Bornholdt, vorm. R. Deutschbein. Aneroid-Barometer-Fabrik und optische Waaren. Inh. J. Bornholdt" ("J. Bornholdt, formerly R. Deutschbein. Aneroid barometer factory and optical goods. Proprietor J. Bornholdt"). The new owner was in no hurry to drop his predecessor's name. The words "vormals R. Deutschbein" and the founding date of 1853 served the firm as a mark of quality and seniority.
A Reitz–Deutschbein microscope aneroid from about this time, around 1888, survives in the collection of the Geodetic Institute of the University of Hanover.
Deutschbein himself did not give up his craft. From 1887 the address books list him separately from the factory: "Deutschbein, R., Optiker u. Mechaniker, Böhmersweg 6" ("Deutschbein, R., optician and mechanic, Böhmersweg 6"). The house on this residential street in Rotherbaum very probably served as both home and workshop. In 1895 the entry is repeated with the banking note "BCto. Vereinsb.", an account with the Hamburg Vereinsbank and a sign of an independent business.
The house on Böhmersweg remained in the family into the twentieth century. The street directories of 1915 and 1927 list "Deutschbein, R., Feinmechan." ("precision mechanic") at No. 6, in 1927 on the first floor. The owner of the house is recorded as C. F. R. Deutschbein, with the testamentary note "Testam.". The master was already exhibiting his aneroids in 1854, so the precision mechanic R. Deutschbein of 1915–1927 was most likely a member of the next generation of the family, who kept both the initial and the craft.
The name outlived the workshop. Röll's railway encyclopaedia (1890; second edition 1912) set apart a special class: "Aneroide mit mikroskopischer Ablesung (von Reitz-Deutschbein u. a.)" ("aneroids with microscopic reading (Reitz–Deutschbein and others)"). In 1899 Hammer reviewed progress in geographical surveying in the "Geographisches Jahrbuch". He described the "Mikroskop-Aneroid, vom Mechaniker Deutschbein in Hamburg ausgeführt" ("microscope aneroid, made by the mechanic Deutschbein in Hamburg") as of little use for travel but capable of great accuracy where needed. Lueger's "Lexikon der gesamten Technik" (1904) drew a sober conclusion: the Reitz instrument, "obwohl hoher Genauigkeit fähig, hat in der Praxis wenig Verwendung gefunden" ("although capable of high accuracy, has found little use in practice"). In 1919 Emil Warburg, president of the Physikalisch-Technische Reichsanstalt, and W. Heuse opened their article on aneroids with a brief historical sketch. They listed those who had worked especially hard to develop Vidie's invention: Goldschmid in Zurich, Naudet and Hulot in Paris, and "Reitz und Deutschbein (Hamburg)".
Only a few documents tell the story of Robert Deutschbein, but each says a great deal. In 1854, while Vidie's French patent was still in force, the Hamburg mechanic was exhibiting inexpensive aneroids in Munich. In 1858–1859 his instruments, built to Vidie's early design, passed a long assessment by the Patriotic Society and were judged sounder than the French. The master himself was recommended for a silver medal for his perseverance. His movements were sold under resellers' names, and his aneroids travelled to Africa. In 1873 Professor Jordan knew of only two aneroid makers in Germany, Deutschbein and Gabory, both in Hamburg. In the same year Vienna awarded his barometers, among them pocket aneroids on Naudet's design, a Medal of Merit.
Then came the workshop's boldest experiment. Together with the engineer F. H. Reitz, Deutschbein gave up the entire mechanical transmission he had once refined so carefully. He kept only the box, the lever and the spring from Vidie's design and put a microscope in place of the pointer. The first instrument proved temperamental. Over the next eleven years, however, the workshop produced some forty examples and made a pocket travelling version for mountaineers. It refined the design until Hammer judged it twice as accurate as a mercury barometer. The instrument never came into wide use: it cost considerably more than a dial aneroid, was more delicate to handle and was poorly suited to travel. Even so, it was the most consistent attempt in nineteenth-century Germany to replace mechanics with optics in the aneroid.
By the mid-1880s the factory had passed to J. Bornholdt and went on bearing its founder's name for years. The master himself continued to work as an optician and mechanic. His pupil Stäcker founded a firm that outlived both his teacher and Stäcker himself. In the history of the Hamburg aneroid, from Gabory and Krüss to Lessing, Brauckmann and Stäcker & Olms, Deutschbein stands at the very beginning. Sixty-five years after his Munich debut, the Physikalisch-Technische Reichsanstalt named "Reitz und Deutschbein (Hamburg)" among those who had developed Vidie's invention. For a master whom the address books recorded by a single initial, that is a fitting legacy.
All via the Staats- und Universitätsbibliothek Hamburg, Hamburger Adressbücher Digital.
Frog Motif Metal Barometer
