Quo Vadis - International Conference
FIG Working Week 2000, 21-26 May, Prague

Proceedings

by Pavel Hánek and Antonín Švejda

Key words: history of surveying, production of surveying instruments, verification of surveying instruments quality.

Abstract

On the occasion of FIG Working Week Prague 2000 there will be held (within the framework of Prague 2000 European town of culture activities) an exhibition of "Historical Geodesy Instruments from Bohemia" in The National Technical Museum (NTM) from May 15 to July 15, 2000. The exhibit will focus on the two periods associated with advanced economic and political development of the Czech state: the reign of Emperor Rudolf II and the end of the 19th and beginning of the 20th centuries.

An important aspect of preparing for this exhibition has been the testing of the quality of the historical instruments using modern methods based on international standard ČSN ISO 8322 (1996) in addition to some tests which are no longer performed. These results have been incorporated into several thesis studies on geodesy which were defended at the Faculty of Civil Engineering at the Czech Technical University (CTU) in Prague.

2 History

One of the peaks of science advancement in the Czech lands occurred during the reign of Rudolf II (1552 – 1612). In his court, which was significant in Europe, worked the naturalist and doctor of medicine Tadeáš Hájek z Hájku, who conducted the first triangulation of the area surrounding Prague. Thanks to him, Tycho Brahe and Johannes Kepler came to Prague where he designed a new type of astronomical telescope in 1611 and defined the first two laws on the movement of planets. In addition, several important European craftsmen worked for the Emperor. Jost Bürgi (1552 – 1632) became the Emperor’s watchmaker in 1604. In 1610 he compiled logarithmic tables which J. Kepler himself relied on. Erasmus Habermel (+1606) designed a theodolite, levelling and triangulation instruments and artillery direction finder. He also made astronomical instruments, sundials and armillary spheres. The mathematical instruments of Doctor Franciscus Paduarius of Forli on exhibition also come from Habermel’s Workshop. A particularly fine decorative piece in the exhibition is the gilded theodolite with an azimuthal sundials and diagrams of mathematical functions from the period 1608 – 1613. The piece was created by Heinrich Stolle, who collaborated with J. Bürgi.

At the time, outstanding results were achieved in practical geometry which confirms the quality of the instruments. For example, a unique water tunnel was constructed in Prague during Rudolph’s reign. Just before the project was completed in 1593 a member of the court office, Isaac Phendler, made a drawing of it for the Emperor. The scale of the plan is 1: 540, and is also presented in exhibition.

The Thirty Years War brought economic collapse in the Czech Lands and resulted in the emigration of many intellectuals and a general decline in the importance of Prague. Nevertheless, thanks to Kristian Joseph Willenberg (1676 – 1731) and a charter by the Emperor, the Estate Engineering Institute in Prague (which was predecessor of the Czech Technical University) began to offer two-year instruction beginning on January 1, 1707. Lectures were given in arithmetic, geometry, practical geometry (geodesy) and fortress engineering.

In the 19th century, which witnessed economic growth and the Czech national revival, the growing economic influence of the Czech Lands resulted in new workshops devoted to the production of measuring instruments and aids. The first workshop was founded in 1808 by Josef Božek (1782 – 1835), a watchmaker and craftsman at the Prague Polytechnical Institute. His sons František (1809 – 1886) and Romuald (1814 – 1898) continued his work. The Spitra workshop manufactured instruments which were comparable with similar European products of that time. Three generations of this family (František, Václav Michal and Otakar) worked in Prague from 1820 till the end of the century. About 1840, another significant master, Mathias Richard Brandeis (1818 – 1868), started to produce his own measuring instruments. After his death, the workshop was taken over by the firm Haase & Wilhelm. Prague became a centre of this sort of production, and in 1890 there were 24 workshops of this kind; by the end of century there were 40 such firms. Of those craftsmen who did not stay in Prague we have to mention the forester Karl Gangloff (1809 – 1879).

Individual instruments were designed by many Czech specialists. We should note the hypsometer of Karel František Edvard knight Kořistka (1825 – 1906), professor of Prague Technical University. Professor František Müller (1835 – 1900) designed an instrument for graphical levelling. Forester and land surveyor Antonín Tichý (1843 – 1923) designed a logarithmic tachymeter. Professor of Czech Technical University F. Müller and his successor, professor and chancellor František Novotný (1864 – 1918), were authors of the first modern Czech textbook of geodesy (Compendium geodesy higher and lower, Prague (1884 – 1913).

In 1883 brothers Josef (1861 – 1945) and Jan (1863 – 1897) Frič established in Prague the family firm which, till the beginning of the 1950s, manufactured a full range of geodetic instruments and aids including a two-second triangulating theodolite 6R. In 1884 / 85 the firm made a small series of mining theodolites under the name of DUPLEX. The divided circle used in these instruments were made from glass for the first time in the world. The firm of Eichler was another important manufacturer in the town of Ústí nad Labem in the first half of the 20th century. Srb and Štys was a firm founded in 1919 and its successful department of geodesy was taken as a base for the national enterprise MEOPTA Košíře after 1945. They successfully overcame the obstacles caused by World War II and went on to attain high levels in European production. In 1961 Czechoslovak technical experts learned about the development of new full range of the theodolites. Shortly after this announcement production was stopped.

The Koula factory manufactured photo reproduction instruments and instruments for the evaluation of photographs. Between 1930 and 1935 the factory supplied semiautomatic and fully automatic aerial chambers to the Czechoslovak Army. Hand aerial chambers were also produced by the Prague firm HAAGER. Photogrammetry instruments were designed and produced by Prague’s firms A. LÖSCHNER and V. KOLÁŘ.

Ass. Prof. Pavel Hánek, PhD
Czech Technical University of Prague
Faculty of Civil Engineering
Department of Special Geodesy
Thákurova 7
16629 Praha 6
CZECH REPUBLIC
E-mail: hanek@fsv.cvut.cz

Dipl. Ing. Antonín Švejda
National Technical Museum Prague
Exact Sciences Department
Kostelní 42
17078 Praha 7
CZECH REPUBLIC
E-mail: antonin.svejda@ntm.cz

Historical Surveying Instruments from Bohemian Regioan

On the occasion of the FIG Working Week Prague 2000, „Exhibition of Historical Surveying Instruments from Bohemian Region" is taking place in the National Technical Museum in the period of 15.5. - 15.7.2000 within the action Prague 2000 – European City of Culture.

The authors of this contribution, who are also the authors of the exhibition topic, informed the scientific public about the history of manufacturing of surveying instruments in the Czech lands at the XXI. FIG Congress in Brighton (Hánek, Švejda 1993). The exhibition is complemented with a production of photogrammetric instruments and tools. The focus of the exhibition is – in accordance with the economic and political development of the Czech state – the time of the rule of Emperor Rudolph II and the turn of the 19. and 20. centuries. Besides the National Technical Museum, an organiser of the exhibition, the exhibits were borrowed also from collections of the Technical Museum Brno, the Technical University Ostrava – the Faculty of Mining, the Departments of Geodesy of the Faculty of Civil Engineering, CTU Prague, and also from the private collections.

The part of preparation was a verification of surveying instruments quality in accordance with the international standard ČSN ISO 8322 (1996), with a completion of parameters, which have already been nearly forgotten. The verification was an objective of some diploma works conducted at the Department of Special Geodesy and defended at the Faculty of Civil Engineering, CTU Prague. The short review is listed in the conclusion of this contribution.

One of the peaks of the science flourishing, the part of which was also a surveying instruments production on our territory, is the period of the reign of the art-loving Renaissance ruler Rudolph II. (1552 – 1612). In 1583, he moved his seat to Prague, which became a significant European metropolis, attracting specialists of all fields. At the imperial court, the notable scientist and doctor Tadeáš Hájek from Hájek, known also as an author of the first triangulation of the Prague’s area, was working. Due to him the renowned astronomers Tycho de Brahe and Johannes Kepler, who also cooperated on the instruments construction, came to Prague. Around 1610, Kepler designed his type of the so-called astronomic telescope, which is widely used even in geodesy. Besides these scientists, some significant European mechanics were also working at the imperial court. Many of their masterpieces soon spread out or were lost in the Thirty Years’ War (1618-1648). All the collection from the aforesaid period comes from the collection of the National Technical Museum (Švejda 1997).

The famous Jost Bürgi (lat. Iost Byrgi, 1552-1632), Swiss by origin, worked on the Dukes of Hessen court, which belonged to one of the prominent European scientific centres. Since 1602 his works had been protected by the imperial privilege, a certain precursor of the patent protection. In 1604, he became the Emperor’s watchmaker. An instrument for perspective drawing, working on the basis of a theodolite, is dated with the year 1604, too. In 1609, Jost Bürgi made for the Duke of Hessen a precise triangulation instrument, based on the triangles similarity, which is today a pride of the collection of the Museum in Kassel. In 1610, J. Bürgi assembled, according to J. Kepler, who himself used them, logarithmic tables. Even if he surpassed John Napier, he was hesitating with the publishing for ten years, so that John Napier had published it before him. The Bürgi’s type of ratio compasses from the 17. century is also presented at the exhibition.

Another eminent creator was Erasmus Habermel (?-1606). He is an author of theodolites, the levelling instrument, and the triangulation and artillery surveying instruments, which are mostly in foreign collections. A part of the world-renowned collection of gnomonic instruments installed in the National Technical Museum in Prague (NTM) is the functional and by its artistic manufacturing, perfect equatorial sundial clock with altimeter. The exhibited collection of mathematical instruments (ratio compasses, mason’s levels, compasses and drawing instruments), fabricated for the Emperor’s physician Franciscus Paduanius from Forli, also comes from Habermel’s workshop.

A decoration of the exhibition is the gilded brass theodolite with the azimuthal sundial clock and an extensive set of mathematical functions (e.g. goniometric functions, lengths of triangles sides) coming from the years 1608-1613. The author is Heinrich Stolle, a co-operator of aforesaid J. Bürgi.

The mentioned instruments were, for their purpose, certainly rather exceptional. Nevertheless, the surveying practice itself reached excellent results, which is an evidence of the high level of the commonly used instruments. The construction of the unique water tunnel (the so-called Rudolph’s Tunnel), finished after eleven-year-work in 1593, is an excellent example. The straight tunnel, with a diameter of (0.7-1.5) x (3-4) m approximately, traverses mostly natural rock, 43 m under the surface at maximum. It is 1.1 km long with an elevation of the ends of only 1.12 m. The tunnelling was performed from both ends simultaneously, on the route there were 4 vertical shafts, sunk from the surface. (Note: the tunnel is running near the building of NTM). Outstanding engineers of that age gathered at the tunnel construction. Just before the tunnel finishing, a clerk of the court office Issac Phendler drew for the Emperor’s information a front view map at a scale of 1:540 (Hánek 1994). A modern copy is presented at the exhibition.

The events of the Thirty Years’ War brought on our territory, little by little, an economic collapse, an emigration of many intellectuals and an overall decline into the provinciality, which also affected fine mechanics. In the following years only small surveying, mapping and drawing tools or unique pieces, manufactured on commission, were produced in small workshops. This period is at the exhibition represented by the mining instrument, the so-called schinzeug, the all-circle astrolabe, or the telescopic drawing board (sketching pad), designed by Reitzenstein.

It is good to remind at this place that it was just an imperial engineer Joseph Christian Willenberg (1676-1731), at whose initiative and request from 1705, the Estates School of Engineering in Prague was established. This institution, which was a precursor of today’s Faculty of Civil Engineering, was founded on the basis of the Foundation Charter, issued by Emperor Joseph I and written in Czech. Two-years teaching included arithmetic, geometry, practical geometry, the so-called geodesy, and military engineering. A distinguished professor of Prague’s Engineering School, František Linhart Herget (1741-1800), was the leading surveyor and the examiner of united estate cadastre, founded in 1785 by Emperor Joseph II (1741-1790). He also issued certificates for the designed surveying instruments.

In the 19th century, connected with the industrial revolution and the Czech National Revival, a recovery of surveying instruments and tools arouse. It corresponded to the increasing economic influence and development of Bohemia within the Habsburg monarchy. The first mechanical workshop was founded in 1808 by Josef Božek (1782-1835), who had been since 1805 a watchmaker and mechanic of the Prague Polytechnic Institute. A successor in his function and the workshop became his son František (1809-1886), and also his second son Romuald manufactured instruments. They both continued in the manufacturing of individual, often unique scientific instruments, including surveying instruments. Above the average, in comparison with other European production, works signed by the name Spitra excelled. Three generations of the family (František, Václav Michal and Otakar) were working in Prague since 1820 till the end of the century. Roughly since 1840, another outstanding master, Mathias Richard Brandeis (-ys; 1818-1868), was manufacturing surveying instruments. After his death, the firm Haase & Wilhelm overtook his workshop. At the exhibition these very producers are represented by the extensive collection of angular and levelling instruments, topographic sets diopters and a heliotrope.

In 1890, there were in Prague, the centre of production, twenty-four workshops producing surveying instruments, at the end of the century there were even four dozens. As for the quality, the company Strejc & Dušek was the best among producers of drawing sets. From the designers and producers outside Prague, the most remarkable one was Karl Gangloff (1809-1879), a head forester in Rožmitál under Třemšín. He was an author of many tools and aids for the so-called forestry geodesy, various types of dendrometers and planimeters in particular. In the first half of the 20. century, the company Eichler, whose production is at the exhibition represented by a universal theodolite, had its seat in Ústí upon Labe.

Many Czech specialists designed individual instruments – often for companies in Vienna. To name at least a few: the hypsometer designed by a distinguished professor at the Prague’s Polytechnic, Karel František Edvard Knight Kořistka (1825-1906), the instrument for graphic levelling by Professor František Müller (1835-1900) or the logarithmic tachymeter by an outstanding forester and railway surveyor Dipl. -Ing. Antonín Tichý (1843-1923).

Professor of Prague’s Czech Polytechnic, František Müller and his successor, the professor and rector František Novotný (1864-1918), became authors of the first modern Czech textbook of geodesy (very quality four-parts unfinished Compendium of Higher and Lower Geodesy, Prague 1884-1923).

In 1883, a turning point in the hitherto production of surveying instrument arouse, when brothers Josef (1861-1945) and Jan (1863-1897) Frič founded in Prague „the Shop for the Precise Mechanics". The area of interest and a creative invention of both brothers were very broad. Besides the designing and the production of manufacturing instruments for an equipment of their own shops, they also constructed a polarizer and an analyser, and also a bareoscope for the indication of the sugar juices density. They also designed machines for the division of circles of surveying instruments, for grinding of lenses, and many other constructions. Their participation at the General Land Exhibition in Prague in 1891 ended with a big success. After 1906 the enterprise J. & J. Frič produced a polarimeter for sugar content indication, which was accepted as the official standard in the USA.

The family led enterprise of the Frič Brothers was during its existence producing the whole assortment of surveying, mapping and cartographic instruments and tools, including the prestigious triangulation theodolite 6R with the screw micrometers and reading by estimation up to 2² , and special instruments for the measuring of the dam deformations and the tunnel constructions. The enterprise closed down after its nationalization at the beginning of 1950s’, when it was within the national enterprise Metra switched to another production.

In 1884/1885, a small series of mine theodolites DUPLEX, in which for the first time in the world a divided ring of glass was utilized, was produced. The horizontal ring with 130 mm in diameter was made up from the 8 mm thick mirror glass. At the upper edge it was divided with diamond chisel by 1° , the numbering was engraved with the pantograph of Milanese type with 25x reduction. The engraving was filled with graphite powder. The ring was illuminated with a burner through a small window at the bottom of the ring cover. The angle minutes were read directly, by estimate 30² , by means of two opposite microscopes with 24x magnification, with the optical axis bent by a prism. The theodolite was universally usable for angular measurements (astronomic connections at the surface, and polygonization and steep measurements under the surface), but also for levelling. The Frič Brothers posed themselves 17 conditions for the construction of the repeating instrument with fine settings. Many of them are commonplace today (e.g. folding tripod, fixed and flexible fastening, nadir and zenith centering, reversible telescope with a visor illumination of a viewing field, covering of rings and other parts, and a possibility of the complete rectification of all mechanical axis relations). The Duplex had a height, including the setting level, of 28 cm and the width of 21 cm, which is roughly half of the usual sizes of that time. For easy targeting in vertical planes, two telescopes of variable lengths were chosen. The axis of the telescope for very steep measurements went through the concave turning axis of the top and insertion telescope with the reverse levelling tube and it was in the objective part (on the opposite side of the vertical metal ring with verniers) rectangular bent. A description of the construction was published in 1886 in the prestigious journal „Zeitschrift für Instrumentenkunde“ (Frič J. & J. 1886).

At the exposition in Brussels in 1888, another remarkable novelty was presented, a hanging mining measuring compass of Kassel type with a vernier needle. Lateral oscillations of the knife needle were dumped with a friction mica disk so effectively that it might had been at the both ends equipped with verniers. The compass was divided into the traditional 24 hours, the smallest section of the ring had the value of 2^m, a section of the vernier 10^s, i.e. 2¢ 30² in the sexagesimal ring division into 360° .

On the basis of the brilliant idea of Prof. F. Nušl, the construction of astronomic-geodetic circumzenithal instrument for definition of geographic coordinates by the method of the same heights was solved out. The advantage compared to astrolabes was, among others, a vertical division of the picture and a placement of the mercury horizon in the centre of the instrument. In 1932, the impersonal micrometer, according to the design of Prof. E. Buchar, was constructed. In 1970s, the construction was further improved by the Research Institute for Geodesy, Topography and Cartography (VÚGTK in Czech, now located in Zdiby), which is producing the instrument under the name 1000/100. The same staff constructed other astronomic instruments – the so-called diazenithal and radiozenithal instruments.

It is obvious that all mentioned surveying instruments are presented at our exhibition.

In 1919, shortly after the formation of independent Czechoslovakia, the optical-mechanical enterprise Srb & Štys was founded in Prague. The company was rapidly developing mainly thanks to military commissions. The new enterprise introduced the modern system of factory production and gained a number of excellent mechanics from the Frič Brothers Company. Since 1923, the whole range of surveying instruments and tools (rods, planimeters, clinometers, pantographs, sets of drawing instruments) was being produced.

The instruments for special purposes, e.g. for the water level measuring, were also produced. Among the most successful constructions we can name the nice triangulation theodolite with screw microscopes with reading precision by estimation of 1² ; the school theodolite Th Š; the theodolite TN 25; and the technical levelling instrument NN 25. A two-pictures distance-measuring adapter was also very popular.

After 1945, on the foundation of the geodetic department of the Srb & Štys Company, the national enterprise Meopta Košíře, which adopted the manufacturing programme, was established. A lot of designers from the old firm started to work in the newly established enterprise, e.g. A. Holý, Höger, A. Dvořák, who during the short time caught up a delay, caused by the war and reached a solid European standard. In the catalogue from 1961, the modernized version of theodolite TH 30 with metal rings and readings by verniers of 30² , but also a construction of the theodolite Meopta T1^c from 1955 with glass rings and reading by simple optical micrometer enabling estimation of 2 mgon (2^cc). For the army it was equipped with a periscope. In the catalogue there was also a balloon (meteorological) theodolite, a topographic set, a base-measuring bar, a construction levelling instrument NK 30x with a glass minute ring, an older small (the so-called pocket) instrument KNK 8.8x, and the novelty MN 10x. There were also a plotting cartographic set and plates there and a very popular triple pentagon.

In 1961, the Czechoslovakian professional public was acquainted with the development of a quite new series of theodolites with very good function and design. (Type MT 0, magnification 15x, reading of 5^c, MT 10, 28x, 1^c, MT 11 with an automatic index of vertical ring, MT 20, 28x, 10^cc, and MT 30, 34X, 1^cc). The series was complemented with school and compass theodolites and of course with a complete line of accessories. None of these instruments was used in practice, because already in 1963 the production was suddenly abolishes and delimited within the Council of Mutual Economic Help; the enterprise with the new production programme was incorporated into the enterprise ZPA. The situation in the production of levelling instruments was slightly better. The new type MN 20 with a micrometer, designed for the accurate levelling, and the building type MN 10 were developed and their production launched. The last produced model was elegant MNK 20 for the technical levelling with an automatic adjustment of measuring line by means of a compensator.

The tradition of photogrammetry is on the Bohemian territory, which was a part of Austrian-Hungarian monarchy, very rich. After the formation of Czechoslovakia, succesful civil firms were established; the Czechoslovakian Military Geographic Institute continued in work launched by the Military Geographic Institute in Vienna. The enterprise Koula in Prague produced quality photogrammetric and photoreproductive instruments. On commission of the army in 1930-1935, the enterprise supplied semiautomatic and automatic aerial cameras, types A-I-25 and A-II-30, with the size of 13 x 18 cm, a blind shutter and a focus length up to 500 mm. Besides, there were small instruments for a quick pictures evaluation: a sketch master, a mirror stereoscope, and a drawing stereoscope. Another Prague’s firm Haager supplied the army with a hand aerial camera, e.g. type A-VII-38. The other Prague’s companies A. Löschner and V. Kolář also designed and produced photogrammetric instruments before the II. World War. The Mahr-Kolář rectifier with a bent optical axis leading to the considerable height reduction was excellently designed, but it stayed only at the prototype level. The Zbrojovka Brno Company produced in 1933 stereoautograph for a terrestrial pictures evaluation in dimension of 6 x 9 cm.

Prof. F. Svoboda designed and with his co-operators constructed the series of geodetic-astronomic instruments at the astronomic observatory of CTU Prague. The mirror instrument, the so-called almukantar for geographic latitude measuring from 1937, is the most known.

After the II. World War there were, besides the enterprise Meopta, other small manufacturers. The aforesaid Research Institute of Geodesy, Topography and Cartography constructed electronic hydrostatic levelling sets HYNI, controlled by computer, and produced one of the first prototype of luminous distance meters, supplied invar steel bands, and it has produced an adapted construction of the so-called cirkumzenithal till now. Ring tachymetric rules Cirta, polar coordinatographs and orthogonal plotting sets were also produced in the enterprise Meopta. Currently, reflecting prisms of distance meters and other small tools are being produced in the Czech republic.

In years 1996-2000, six diploma theses dealing with a verification and completion of parameters of the Czech production instruments, mainly from the turn of the 19. and 20. centuries, as well as with a determination of their quality in accordance with the Czech International Standard (ČSN ISO 8322/1996) were defended at the Department of Special Geodesy of the Faculty of Civil Engineering, CTU Prague. Even if such a verification of exhibits does not give a precise picture of their properties in the time of their practical usage, we presume that they can considerably contribute to the classification of collection or to the study and analysis of older engineering works yet.

The prerequisite of the verification, according to the ČSN ISO Standard, is measuring with the tested instrument in two different days, always in one series. Regarding theodolites, a series consists of measurements of 4 horizontal directions, placed on the whole ring in 3 groups without a closure, or a measurement of 4 vertical angles measured on points with various elevations, respectively. The result are standard deviations s_φ of a horizontal direction and vertical (or zenith) angle s_ζ, always for measurement in two positions. For theodolites equipped only with the segment of a vertical ring, the value s_ζ relates to the measuring only in one position. Levelling instruments are for a determination of the standard kilometre deviation s_km of double levelling tested on the path, long 240 m with stabilized lengths, sight line 20 m. One series consists of 5 two-ways measuring. The non-typical instruments, e.g. tubular liquid clinometer or levelling diopter, were also tested by this procedure. The magnification of telescope was determined in the laboratories of the Department of Higher Geodesy. The constant of a cross-wires distance meter and its addition constant were determined from the levelling of measurement on the bases of the known lengths. The accuracy ranges from 0.1-0.2 of the unit, 1-2 cm respectively.

In depositaries of NTM, the basic set of angular and levelling instruments and the so-called universal levelling instruments, nowadays called rather tachymeters (theodolites) with a sensitive levelling tube, was chosen. The basic parameters of some instruments, chosen from the whole set to characterize the given designed group, are shown in Tables 1, 2, 3 (Hánek 1999). Dimensions, mass weight, index levels sensitivity, telescope lengths in the edge positions of focusing etc. are stated in diploma theses.

Instruments were before the measuring carefully cleaned and rectified, according to the original procedures. Because of the shortage of original statives, the adapters on Zeiss statives were made. The common bars with E division were used for levelling instruments. They were for tubular clinometer and levelling diopters complemented with sliding circular target, horizontally divided with a contrast colour. The level sensitivity was determined from repeated measurements on the rectified rule with accuracy of 1² approximately. At the cross alidade levels, the level sensitivity perpendicular to the sight line is given at the first place, after the slash a sensitivity of a longitudinal level or a level placed on the telescope fork, follows. The sensitivity of striding levels or levelling bubbles of theodolites is in Table 1 given with an abbreviation of location in a column „other levels". In Table 2, there are levelling instruments with a fixed telescope. The exception is the Spitra’s instrument, equipped with the free telescope.

Table 1: Theodolites

Table 2: Instruments for determination of elevation

Table 3: Universal tachymetres (with a sensitive levelling bubble)

Instruments of the Haase & Wilhelm production do not have production numbers; an inventory number of NTM is quoted

References

Frič J. & J., 1886: Der neue Grubentheodolit "Duplex". Zeitschrift für Instrumentenkunde 6, č.7, s. 221-232 a č.9, s.305-308

Hánek, P., 1994: A Renaissance Period Front-View Map Depicting the Emperor Rudolph's Adit. Proceedings IX Congress ISM, Prague, p. 158-161

The Czech Standard ČSN ISO 8322, 1996: Verification of Surveying Instruments Quality in Investment Construction. Part 3: Theodolites. Part 5: Levelling Instruments. (In Czech)

Švejda, A., 1997: Science and Instruments. In: Rudolph II and Prague. Prague’s Castle Administration, Prague.

Hánek, P. - Švejda, A., 1998: To the History of the Production of Geodetic Instruments in Bohemia. XXI Congress FIG, Brighton. Papers from the ad hoc Commission History of Surveying, s. 59-67, Papers from commission 1 & 11, p.417-425

Hánek, P., 1999: To the History of Surveying Instruments v Bohemia. 7. Mine Surveying Conference – Current Problems of Mine Surveying and Geology. Association of Mine Surveyors and Geologists, Nový Hrozenkov, p.49-56. (In Czech)

PICTURES

	Brandeis
	Frih
	Frih Dup
	Meopta T
	Schinzeu
	Spitra
	Stolle

Ass. Prof. Pavel Hánek, PhD
Czech Technical University of Prague 
Faculty of Civil Engineering, Department of Special Geodesy
E-mail: hanek@fsv.cvut.cz

Dipl. Ing. Antonín Švejda
NTM Praha, vedoucí odd. exaktních věd
E-mail: antonin.svejda@ntm.cz

29 April 2000

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