The Great Men of Croatian Science

Complete information is available only in Croatian

Nenand Trinajstiæ

The greatest Croatian Men of Science presented in this section testify to the existence of a tradition going back to the twelfth century. Some of these Greats made scientific contributions which were true turning points in the history of science. The most eminent among them where certainly Herman Dalmatin (12thc), Franjo Petriæ (16th c), Josip Rugjer Boškoviæ (18th c) and Andrija Mohorovièiæ (20th c). These Greats along with others contributed to the development of European and world science although they were often not identified as Croats. Thus for example the greatest Croatian scientist Boškoviæ has been claimed by many countries. This is because many Croatian scientists were educated abroad and spent most of their active lives in scientific circles outside their homeland. Of the sixteen great Croatian scientists in this section only the Mohorovièiæ - the father Andrija and his son Stjepan - along with Spiridion Brusina and Dragutin Gorjanoviæ-Kramberger spent their whole life in Croatia.

The lives and works of these great scientists show that science existed among the Croats almost from the beginning of 75 their settling in this part of the world. However, Croatia was often unable to secure the best conditions for research, which was the reason why in certain historical periods they found their scientific home elsewhere. Some left their country because their ideas were not understood or sometimes because their life was in danger. Others could not realize their ideas in a small and poor country under foreign domination. And some were simply too ambitious to be satisfied by what their homeland cwas able to offer. However, they all remained attached to it, and carried it in their heart no matter where they lived. Those few who spent their life here often did not get the recognition they deserved and were even prevented from doing their research. An extreme example of the latter is the case of Stjepan Mohorovièiæ whom many now consider the most significant Croatian physicist in the twentieth century.In short, it was the destiny of Croatian scientists to struggle no matter where they lived - at home or abroad. But in spite of unpropitious conditions they worked and strove to make the world a better place to live in. This exhibition is a tribute to their effort.

HERMAN DALMATIN
HERMANNUS DALMATA

Herman Dalmatin ( Hermannus Dalmata, Sclavus, Secundus, De Carinthia) natural philosopher and translator from the Arabic language (about 1110 - after 1143) is the earliest Croatian scientist and philosopher, and one of the greatest. He was born in central Istria, and studied at the Cathedral School at Chartres and in Paris (1130-1135). After completing his studies he travelled to the Middle East with his friend Robert from Ketton, where both were seriously involved in the study of Arabic science and philosophy. In 1138 we find them in a place along the river Ebro in Spain working on translations. At that time Herman was mostly translating works of astrology. In 1138 he translated the astrological treatise Fatidica, the sixth part of a work in astronomy by a scientist of Jewish origin Sahl ibn Bishr; in 1140 he translated Introductorium in astronomiam by Abu Ma'shar contributing thereby to the spreading of Aristotelian philosophy in western Europe. At the same time Herman wrote the astrological works Liber imbrium and De indagatione cordis, compilations from Indian and Arabic texts. Petrus Venerabilis, the Abbot of Cluny met Herman and Robert in Spain in 1142 and encouraged them to translate the Koran. In Leone Herman finished some shorter texts about Islam De generatione Mahumet and Doctrina Mahumet. The joint work of Herman and Robert on the Koran and Herman's texts on the Islam had considerable importance in acquainting scholars in Christian Europe with the Islamic religion. After leaving Spain Herman went to France, working in Toulouse and Beziers where he translated Ptolomeus' Planisphere and revised the translation of Euclid's Elements made by Adelard from Bath; He also revised Adelard's translation of the astronomic tables composed by Muhammed ibn Musa al-Kwarizmi. He probably wrote about the astrolabe, but these texts are not firmly attributed. He may also have translated at least some excerpts from Ptolomeus' Almabest. He gave an outline of his original thinking in the work De Essentiis which he completed in Beziers in 1143. This work is based on Aristotelian ideas which Herman found in Abz Ma'shar's work and on the Platonism he learned at Chartres. He also added some astrological concepts found in Arabic philosophers. In this work an important role is given to five essences: cause, motus, tempus, locus, and habitudo. In this work he also expounds his views on astronomy. With De essentiis and the translation from Abu Ma'shar Herman influenced Rudolph from Bruges, Domingo Gonzales (Gundisalvi) and Daniel from Morley who lived in the twelfth century. These two works together with his translation of Ptolomeus were influential throughout the Middle Ages.

FRANE PETRIÆ

Frane Petriæ (Lat. Franciscus Patricius) is one of the greatest Croatian scientists, a Renaissance philosopher, polyhistor, erudite, the last of the great representatives of the neo-Platonist school in Italy. Born on the island of Cres in 1529, he was educated in Venice, Ingolstadt in Bavaria (under the patronage of his relative Matija Vlaèiæ) and in Padua. After completing his studies he worked in various capacities in Cyprus, Italy and Spain. In 1577 Petriæ was elected to the chair of Plato's philosophy at the University of Ferrara. This was the beginning of his most productive period when he published the bulk of his work, achieved a high reputation and became member of several academies in Italy.

Upon invitation by his former colleagues from the University of Padua Nicola Sfrondati who became Pope Gregorius XIV (1590-1591) and Ippolito Aldobrandi, the cardinal who later became Pope Clement VIII (1592-1965), in 1592 Petriæ took over the chair of Plato's philosophy at the distinguished Roman university La Sapienza. Shortly after that his book Nova de universis philosophia was placed on the index of forbidden books and Petriæ withdrew from public life. In 1596 he became member of the Croatian Fraternity of Saint Jerome in Rome. He died on February 7 1597, and was buried in the church of Saint Onophrius in Rome, in the tomb of the great poet Torquato Tasso who was his opponent after Petriæ published a work in defence of Lodovico Ariosto in Ferrara 1585.

Nova de universis philosophia is Petriæ's most significant work. It is a synthesis of the spirit of his time marked by Neoplatonism which in the course of the sixteenth century was abandoning the peripatetic approach in favour of entirely new concepts and preparing the terrain for the rise of natural science and natural philosophy. Writing in the spirit of Neoplatonist Renaissance philosophy, Petriæ was an original thinker, transforming received ideas into new theoretical form and investing them with meanings innovative in his time. In this sense owing to his originality and an exceptional grasp of the entire field of philosophy, he surpassed his contemporaries and laid the foundations for the development of science in the Modern Age.

FAUST VRANÈIÆ
FAUSTUS VERANTIUS

Faust Vranèiæ (Faustus Verantius) was born in 1551 in Šibenik. He studied in Padua and in Hungary. He was interested in physics, especially mechanics. His education was in the care of his uncle, the noted diplomat and Archbishop of Hungary Antun Vranèiæ. After completing his education Faust served as secretary at the imperial court of Rudolph II in Prague, where he met numerous scientists and engineers in the Emperor's service. After some time he took religious orders and rose to the rank of bishop. He then joined a religious order and went to Rome and finally Venice, where de died in 1617. He was buried, according to his wish, in the parish church in mepurine on the island of Prviæ near Šibenik.

As a scientist Faust Vranèiæ was a polyhistor, and wrote philosophical and historical works. However, his most notable works were his Dictionarium in five languages published in Venice in 1595 (with two reprint editions very important for Croatian cultural history) and the work Machine Novae. Machine Novae went through two editions. It is believed that the first edition which includes 48 copperplate engravings and a text in Latin and Italian was published in Florence in 1615.

The second edition which includes the same engravings, and texts in Latin, Italian, Spanish, French and German, was probably published in 1615 or 1616 in Venice.

Today copies of Machinae Novae are very great rarities, with only a few copies of both editions kept in world libraries. One copy is in the Civic Museum of Šibenik, and copies of both editions are at the National and University Library in Zagreb. Faust Vranèiæ himself engraved the forty-nine fine engravings which are graphic representations of fifty-.six various apparatus and technical devices described in his text.

The technical problems discussed in Machinae NOvae cover a very wide range. Contemporary historians of the technical sciences believe that the basic characteristics of Vranèiæ's technical devices are the simplicity and clarity with which they have been conceived and presented. His proposals and descriptions are aimed at satisfying people's everyday needs and are always applicable in physical and technical reality. In search of a solution to a problem Vranèiæ relies on his realistic, experimental and critical intellect. Describing machines and devices he Vranèiæ always refers to the models and sources, that inspired him, but also clearly indicates his own original work.

Some constructions presented in Machine Novae are particularly significant because Vranèiæ was the first to present them - such as the metal chain bridge. In the perspective of technical history, culture and civilization Machinae Novae remains a fascinating achievement. This work was reprinted three times abroad: in Germany (1963), in Italy (1962) and in Hungary (1985). Upon the initiative of the "Juraj mižgoriæ" civic library in Šibenik a very handsome reprint edition of Machinae Novae in Croatian translation for the first time, was also published in Croatia by Novi Liber in Zagreb. In this way this capital work by Faust Vranèiæ from Šibenik has become accessible to a wide circle of Croatian readers.

MARKO ANTUN DE DOMINIS
LATE RENAISSANCE PHYSICIST

Marko Antun de Dominis (1560-1626) wrote both his works in natural history as a magister of mathematics at the Jesuit Grammar School in Padua about 1590. He polished and published them only twenty years later when he was Archbishop of Dalmatia - Primas Dalmatiae et Croatiae.

Inspired by Galileo's discovery of the telescope in 1609, Dominis published his treatise De radiis visus et lucis in vitris perspectivis et iride (On the Rays of Sight and Light in Lenses and the Rainbow) in which he gave a theoretical analysis of the functioning of the telescope and the phenomenon of the rainbow. After numerous experiments with lenses Dominis arrived at a correct qualitative notion of the refraction of light rays speculating about conditions under which a combination of lenses would work in the manner of Galileo's telescope. Experimenting with glass spheres filled with water, he found that light was reflected even on the inner wall of a raindrop, which helped him to explain the forming of the inner arch of the rainbow.In the course of the eighteenth century Dominis' theory of the rainbow was discussed by numerous notable scientists ranging from excessive praise given by Newton and Christian Wolff to critical reactions by Christian Huygens, RuÐer Boškoviæ and Joseph Priestley. At the beginning of the nineteenth century he earned the praise of Goethe in his Zur Farbenlehre.

In his work Euripus Dominis offered an explanation of high and low tide with the help of the transpolar circle. This explanation promted his systematic argumentation in favour of the roundness of the earth, defining the surface of the earth as stretching like a plane on calm sea level across land as well. He also proposed to introduce two constant adjoining meridians on the globe "so that when the day of Lord's Nativity began in the eastern parts, in the western parts St Stephen's day would also promptly begin."

There is however one dimension of his work that will always remain a mystery: his manuscripts. They were burned together with his earthly remains and his portrait at Campo dei Fiori in 1624.

ÐURO ARMENO BAGLIVI

Ðuro Armeno Baglivi , the most famous physician of Croatian descent, and one of the most distinguished physicians of the seventeenth and eighteenth century, was born in Dubrovnik on September 8 1668. He acquired a fine humanistic education at the Jesuit Collegium in Dubrovnik, which he attended to the age of fourteen, studying classical languages, literature and peripatetic philosophy. At the end of 1683 or beginning of 1684 he went to Lecce in Apulia where he became a student of the physician Pier Angelo Baglivi, his adoptive father. He began his medical studies at the age of fifteen in Naples. He continued and completed his studies in Salerno in 1688. Towards the end of 1688 and at the beginning of 1689 he stayed with his father in Lecce, going on to Dubrovnik and travelling in Dalmatia which together with Dubrovnik he always considered the country of his origin. Then he returned to Italy.

His excellence came to the attention of the famous physician Marcello Malpighi of Bologna, the pioneer of microscipic anatomy and the greatest experimentator of his time. In 1691 Malpighi employed him as his personal secretary and assistant.

In 1693 Baglivi began writing his first scientific treatise about the tarantula. His treatise on the sting of this poisonous spider, De anatome, morsu, et effectibus Tarantulae was completed in 1695. He went on to work on his manuscript of his first and most important book De Praxi Medica, which was printed in 1696. The sudden death of his mentor Malpighi (1694) and the support of the Pope made a momentous turn in Baglivi's life. He succeeded Malpighi as the physician of the Pope Innocentius XII, and in September 1696 was elected Professor of anatomy at the Sapienza Arch-Lyceum, one of the most distinguished institutions of higher education in the world.

He soon gained the reputation of excellent lecturer and diagnostician. The newly elected pope Clement XII also chose him as his personal physician and appointed him professor of theoretical medicine at La Sapienza in 1701. As a sign of gratitude Baglivi dedicated to the Pope his most outstanding work in experimental anatomy dealing with the composition and function of the human organism. The book entitled De fibra motrice et morbosa, nec non de experimentis, ac morbis salivae, bilis, et sanguinis ... Epistola ad Alexandrum Pascolum was first published in Perugia in 1700. Considerably expanded, the book Specimen quatuor librorum de fibra nmotorice et morbosa dedicated to the Pope, was printed in Rome in 1702. In 1704 the first edition of Baglivi's Collected works was printed in Lyon under the title Opera omnia medico-practica et anatomica (his standard complete works were published in 1710). Up to 1842 Baglivi's works went through numerous editions all over Europe. They were translated into English, French, German and Italian. The reputation of Ðuro Armeno Baglivi was also reflected in his numerous memberships in the most distinguished learned societies of his time such as The Royal Society in London (1697), the German Academia Caesareo Leopoldina Naturae Curiosarum (1699), The Italian Accademia dei Fisiocritici (1700) and the Roman Arcadia (1699). Ðuro Armeno Baglivi died after a serious illness in Rome on June 17 1707. (B.B.)

MARIN GETALDIÆ
THE CROATIAN APOLLONIUS

Marin Getaldiæ (1568-1626) holds a place apart among all the Croatian scientists, mathematicians in particular, because of the way in which he joined the community of scientists at the turn of the sixteenth century. Inheriting considerable property from a wealthy nobleman living in London, Getaldiæ spent six years travelling in Europe, and had productive meetings with several scientists of note (Michel Coignet at Antwerp, Francois Viete in Paris and Galileo Galilei in Padua). Later, from his Dubrovnik seclusion, he corresponded with some of the great mathematicians and physicists of his epoch (Christoph Clavius, Christoph Grienberger, Galileo Galilei and Karl Guldin). Guldin tried to pursuade him to edit Vietes collected works for a Munich publisher. With Galileo he exchanged published manuscripts. He got most of the scientific news from his correspondence with Clavius and Grienberger, who were the most notable mathematicians of the Jesuit community in Rome.

Although in his letters he sometimes complained of being "buried" alive in Dubrovnik, he did a lot of work there. Getaldiæ's name is closely connected with two famous localities in Dubrovnik. One is Bete's Cave (Bete was his nickname) where he conducted experiments with his igniting mirrors, some of which he made himself in Dubrovnik (1608). The other is Pozvizd, the highest and strategically most important tower in the fortification system of Ston that he was commissioned to build by the authorities of the Dubrovnik Republic in 16o4.

In his first work, which he wrote only after repeated encouragement on the part of Clavius, Getaldiæ made a mathematical study of the parabola. In his Promotus Archimedes his only treatise in physics, he used a kind of hydrostatic scales to compute tables of relative weight ratios among various kinds of matter. He subsequently directed his mathematical research to the recovery of some lost treatises (On Inclinations , On Contacts) by the Greek mathematician Apollonius of Perga and studied mathematical methods for the solution of various problems. Applying algebraic methods to geometrical problems Getaldiæ was just one step away from founding analytical geometry - an achievement which had to wait for Descartes.

The relation between mathematics and the fields of its applications (optics, geodesy) was seen by Getaldiæ as a two-way street. At the beginning, his interest in constructing igniting mirrors led him towards mathematical research of the properties of parabolas. At the end of his life the study of the triangle inspired him to conceive a method to determine the diameter of the earth, but death did not allow him to test the validity of his theory.

Getaldiæ's work had broad and various resonance, from direct quotations of his theorems to literal translation with no mention of his name. His hydrostatic scales measurements expounded in Promotus Archimedes were taken over by the German Kaspar Schott in his work Magia universalis (1658) and his theorems and experiments were copiously and sometimes literally used in the posthumous Opuscula mathematica by the Englishman William Oughtred. Getaldiæ's restoration of Apollonius' s works was transposed into symbolist language by the Frenchman Pierre Herigon in the work Cursus mathematicus (1644). The same restorations also had an echo , in the eighteenth century, in the work of three Englishmen: John Lawson (1764), Samuel Horsley (1770) and Reuben Burrow (1779). Getaldiæ's principal work De Resolutione et compositione mathematica which is innovative in its methodology has unfortunately remained unnoticed.

Recovering Apollonius's works Getaldiæ lacked neither self-assurance nor patriotism. He placed himself alongside Apollonius and Viete by saying: "...and thus Apollonius of Gaul will need the Croatian Apollonius to revive Apollonius of Perga who was snuffed out either owing to the injustice of passing time or because he was buried by barbarians."

RUGIERO BOSKOVICH



SPIRIDON BRUSINA, ZOOLOGIST AND PALAEOLONTOLOGIST

(ZADAR 1845 - ZAGREB 1908)

Spiridon Brusina was a great Croatian zoologist faunist, organizer of scientific work, and palaeontologist malacologist.

From his grammar-school days in Zadar and his studies in Vienna, he showed special interest in the study of marine and fresh-water molluscs, the snails and shells of coastal Croatia. During his student days and after coming to Zagreb, he published what was then the most complete presentations of living molluscs in Croatia, Slavonia and Dalmatia. Working persistently, he collected a mass of data for compiling a presentation of Croatian fauna. He published many books and papers on ichthyology, ornithology and mamalology, collaborated and corresponded with the greatest zoologists of his time, attended many international congresses, and was generally known and respected outside the borders of his homeland. Aware that one man cannot collect the complete fauna of a country, he devoted himself to the fauna of the Adriatic Sea. By the end of his life he had compiled the most complete collection of Adriatic fauna to date, in which he listed as many as 563 Adriatic taxons.

Brusina was a very capable organizer of scientific and research work. He always knew what he wanted and was very determined. He founded and headed the Croatian National Zoological Museum, leaving behind him classified, and professionally and scientifically analysed malacological, entomological, ichthyological, ornithological and mamalological collections. In his desire to gather and organize Croatian natural scientists he worked on the foundation of the Croatian Natural History Society (1885) and its journal with articles in world languages (1886). He organized scientific trips, and led a team of experts in Adriatic research (1894). He greatly encouraged ichthyological and ornithological studies of Croatia. He compiled the first Croatian zoological bibliographies because he was the first to realize the importance of such "data bases", and also the importance of natural science literature. He built up a valuable library from scratch, acquiring many important publications, journals, and series by purchase, exchange for the scientific journals he had established, and by individual and governmental donations. He far-sightedly realized the importance of the sea for Croatia, and was the first to encourage (after 1886) the foundation of a Croatian marine research station, breeding fish, crabs and shellfish for tourist development, etc. He was called the father of Croatian marine biology (T. Gamulin).

Finally, Brusina is a world name in Neogene mollusc palaeontology in south-east Europe. That is what he is best known for outside his homeland. He discovered several hundred new species, even genera, and wrote noted monographs, many papers, which he published in renowned world journals. Other scholars named at least about ten taxons, species and even genera, after him. He did not only preserve a rich collection of unique samples and holotypes in the museum, but also purchased many precious collections made by other collectors and thus saved them from ruin or from sale abroad. He travelled a lot, participated in many world congresses, and was member of many science academies and professional international societies. Generally, Brusina stood out as a fearless Croatian patriot, always stressing that work in natural history was an expressly patriotic activity.

DRAGUTIN GORJANOVIÆ-KRAMBERGER

In the last decades of the nineteenth and in the early twentieth century European thought revolved around the science concerning the development of life in the geological past. The search for proof of evolution in the long course of the development of life forms, including the development of human ancestors, proof that would support or refute the evolutionary concept, were in the focus of public interest. The discoveries of Dragutin Gorjanovia Kramberger (1856-1936), natural scientist, palaeontologist, geologist and palaeoanthropologist, and their scientific analysis greatly contributed to insight into the evolution of living organisms. The evolutionary evidence collected by that tireless scholar is still of fundamental scientific importance. Assistant curator of the National Museum in Zagreb, head of the Department of Geology and Palaeontology, university professor and academician, he gained European renown through the study of fossilized fish, reptiles and mammals in Croatia and surrounding lands. When he discovered the remains of prehistoric man in Krapina in 1899, he achieved world fame. But it was only through a multifaceted, complete and scientific analysis, methodological innovation and inventive interpretation of his discoveries, that he became a world recognized authority. Experts and contemporaries called Gorjanovia the King of the Diluvium. He was the first to prove the existence of diluvian man and therefore the great age of the human race. His outstanding scholarly opus, many works and discussions in geology, palaeontology and palaeoanthropology, published in Croatia and abroad, shows him to be one of the great men of European natural science. He is still often quoted. As a prominent public worker, a citizen of Zagreb and a Croatian patriot, he extensively studied the soil of Croatia, described its special geological properties, and founded its present geological institutions.

NIKOLA TESLA

HIS LIFE AND WORK

Nikola Tesla was born on 10 July 1856 in the village of Smiljani near Gospia. He attended elementary school and lower secondary school in Gospia, and senior secondary school in Karlovac (1870-1873), and studied at the Technical College in Graz. In 1880 he attended lectures at the University in Prague, and then worked in Budapest where he (1882) discovered the principle of the rotating magnetic field, showing its wide application by constructing the first electric motors powered by alternating current.

In Paris he worked in the central office of Edison's European firm, and in July 1884 he came to New York and got a job in Edison's laboratory. In the spring of 1887 he founded his own laboratory with the exclusive purpose "of further perfecting alternating current motors, invented by Nikola Tesla".

Soon followed patents protecting his system for the production, transfer and use of alternating current, the system that is today predominantly used. Tesla's patents were purchased by George Westinghouse, who won a competition for building a hydro-electric power plant on the Niagara Falls with a project based on Tesla's discoveries. This was the final victory of Tesla's system of alternating current. A monument to the genius of Nikola Tesla still stands on the site.

Continuing research in high voltage and frequency currents in his New York laboratory, Tesla arrived at important discoveries that served as the basis for the development of new branches of electrical engineering (electromedicine, radio, radar), and delivered many lectures on these subjects in the United States, London and Paris. On 24 July 1892 he visited Zagreb and delivered a lecture in the Town Hall.

In 1895 a fire destroyed Tesla's laboratory and all the motors and equipment in it, his notes and the technical documentation about his work. This delayed or even completely prevented the development of some of his discoveries. In 1889 Tesla built a new laboratory in Colorado, in which he experimented with the strongest transformers, some of which developed voltages of over 12 million volts. When he returned from Colorado he built a radio station on Long Island near New York that was to make possible connections with the whole world. However, Tesla's final goal was much greater: he wanted to realize wireless energy transfer. This was the only idea he did not manage to put into practice. A lack of finances forced him to stop work on this project in 1906, and this was also the end of his practical research. However, he continued to invent offering ideas and specific proposals for devices to improve the quality of life (equipment for ozone and fertilizer production, an aeroplane with vertical take-off and landing, gauges for measuring the flow of liquids and gases, and especially the friction turbine - a turbine without vanes).

The life of Nikola Tesla ended on 7 January 1943 in the Newyorker Hotel in New York.

ANDRIJA MOHOROVIÈIÆ
(1857-1936)

Andrija Mohorovicia was a prominent Croatian scientist in the field of meteorology and seismology at the end of the nineteenth and in the early twentieth century.

He was born on 23 January 1857 in Volosko near Opatija, where he went to elementary school. He attended secondary school in Rijeka and studied mathematics and physics at the Faculty of Philosophy in Prague in 1875. After graduating, he first taught in grammar school in Zagreb (1879-1880) and then secondary school in Osijek. On 1 November 1882 he began to teach at the Nautical School in Bakar, where he remained for 9 years. In 1891 he was transferred to the secondary school in Zagreb at his own request, and on 1 January 1892 he became head of the Meteorological Observatory on Gric in Zagreb. In 1893 he became doctor of philosophy at Zagreb University. Soon after he was habilitated as private docent, and in 1910 became titular associate university professor. From 1893 to 1917/18 he taught subjects in the fields of geophysics and astronomy at the Faculty of Philosophy in Zagreb. In 1893 he became corresponding member, and in 1898 full member of what was then the Yugoslav Academy of Sciences and Arts in Zagreb. At the end of 1921 he retired, and he died in December 1936. He is buried at the Mirogoj Graveyard in Zagreb.

Work in the Nautical School in Bakar was crucial for the beginning of Andrija Mohorovicia's scientific work. This is where he first came into direct contact with meteorology, which he taught at the Nautical School, and which absorbed him to such a degree that he founded a meteorological station in Bakar in 1887.

When he became head of the Meteorological Observatory in Zagreb (1892) he concentrated on three fields. He gave a scientific interpretation of some meteorological phenomena. In 1901 he was appointed head of the complete meteorological service of Croatia and Slavonia, which he raised to a European level in personnel and equipment. And finally, he gradually extended the activities of the observatory to other fields of geophysics: seismology, geomagnetism and gravitation.

In March 1892 Mohorovicia began the astronomical observation of stars passing through the Gric meridian to establish the precise time. At the beginning of April 1893 he established a network of stations for following thunder storms, and in 1899 he founded hail-defence stations in the Jaska District. At the beginning of 1899 he started a project for research into and harnessing of the energy of the bura in the karst region, because "...this would be so beneficial for our barren littoral".

A. Mohorovicia showed interest in extraordinary meteorological phenomena like the tornado near Novska in 1892, and the vijor (whirlwind) near bazma in 1898. He studied the climate in Zagreb, and in his last paper in meteorology (1901) he discussed the decrease in atmospheric temperature with height.

After the turn of the century Mohorovicia's scientific interest focused exclusively on the problems of seismology. Analyzing the Pokuplje earthquake of 8 October 1909, he advanced insight into the spread of seismic waves of earthquakes with shallow depths spread through the Earth. In these studies he was the first in the world to establish, on the basis of seismic waves, a surface of velocity discontinuity that separates the crust of the Earth from the mantle and which was named the Mohorovicia Discontinuity in his honour. Soon after Andrija Mohorovicia scientists confirmed the existence of this discontinuity under all the continents and oceans.

Mohorovicia's thoughts and ideas were truly visionary and came to expression many years later (the effects of earthquakes on buildings, harnessing the energy of the bura, models of the Earth, deep-focus earthquakes, hail defence, locating earthquake epicentres, seismographs, etc.). The well-known Swedish seismologist M. Bath included Andrija Mohorovicia among the 13 most outstanding seismological researchers in the period from 1900 to 1936.

On 19 December 1936, a day after the death of Andrija Mohorovicia, the Zagreb paper Novosti published the following article: "The scientist Professor Andrija Mohrovicia, member of the Yugoslav Academy of Sciences and Arts, one of the founders of modern seismology, has died. He was a well-known and respected figure in Zagreb, and his scientific work in the field of seismology gained him world renown. He is today considered one of the founders of modern seismology in the world. Doctor Mohorovicia raised the meteorological observatory in Zagreb from modest beginnings to a completely equipped modern institute that enjoyed world renown, especially in seismic measurements. He also organized the meteorological service in Croatia and Slavonia. At the beginning of his scientific career Doctor Mohorovicia devoted most of his energies to meteorology, but he had most success in the field of seismology and he founded the so-called Zagreb School of world renown in this field of science."

STJEPAN MOHOROVIÈIÆ (1890-1980)

THE "FATHER" OF THE POSITRONIUM

As a grammar-school teacher in Zagreb in 1934, Stjepan Mohorovicia published a scientific paper in the prominent German scientific journal Astronomische nachrichten in which he hypothesized about the positronium (the bound state of the electron and the positron), and predicted its existence on stars. Deutsch discovered the positronim experimentally in 1951, and in 1984 the American astrophysicist McClintock discussed that it might be possible to prove Mohorovicia's idea about the existence of the positronium on stars using a space telescope.

In 1982, H.S.W. Massey (University College London) wrote in the Canadian Journal of Physics: "Although Mohorovicia discussed the possible importance of the bound system of the electron and positron in astrophysical circumstances in as far back as 1934... the first experimental proof was not obtained until 1949". In 1966, P.O. Kinell (Forskning Laboratorium Studsvik) wrote in Svensk Kemisk Tidskrift: "The existence of the positronium was predicted by Mohorovicia in 1934 in connection with his study of the spectrum of nebulae..." In 1982, A.S. Ghosh, N.C. Sil and P. Mandel (Physics Department Calcutta) wrote in the Physics Reports: This bound system was predicted by Mohorovicia in 1934..." In 1984, J.E. McClintock (Massachusetts Institute of Technology) wrote in The Astrophysical Journal: "Mohorovicia (1934) discussed the optic spectrum of the positronium and suggested that it may be observed in star spectra. It seems that Mohorovicia's proposal was overlooked in the last 50 years... With a space telescope the positronium lines from space object NGC4151 could be detected..." In 1986, S. Mrowczynski (JINR Dubna-Moscow) wrote in the Physical Review: "In 1934 Mohorovicia suggested the existence of the bound state of the electron and positron". In 1974, S.J. Tao (The New England Institute) wrote in the Applied Physics: "The positronium, an atom that consists of the positron and electron, was postulated by Mohorovicia in 1934".

Stjepan Mohorovicia also made some important scientific discoveries in geophysics, especially: a) He introduced a new method of earthquake analysis and in 1913 gave the first independent confirmation of the theory of discontinuity discovered in 1910 by his father Andrija Mohorovicia. In the standard seismology monograph An Introduction to the Theory of Seismology, 1985, K.E. Bullen and B.A. Bolt wrote: "In 1909 A. Mohorovicia detected two pairs of P and S phases on seismograms of earthquakes in the valley of the Kupa (Croatia)... S. Mohorovicia and Gutenberg discovered similar pairs of phases in two German earthquakes". b) In 1927, Stjepan Mohorovicia published a theory of the origin of the Moon in which he was the first to hypothesize that the Moon has a crust and the Mohorovicia Discontinuity. This hypothesis was proved in 1969 when the crew of the Apollo 11 placed a seismograph on the Moon that made seismic measurement.

In the period from 1914 to 1962, Stjepan Mohorovicia published 41 scientific papers in renowned foreign (mostly German) scientific journals, which is an impressive opus. Until the middle of the sixties, he was the most prolific Croatian physicists in number of scientific publications in international scientific journals. However, due to his temperament, personal and political lack of tact and recklessness, and certainly because of his links with many German physicists before and during the Second World War, Mohorovicia did not gain affirmation for his scientific work in his homeland. Another factor against him were the many years he spent refuting the theory of relativity, although his arguments against Einstein's theory were at first strictly scholarly. He was also scientifically isolated because he did not follow the trends of modern quantum physics.

LAVOSLAV RUZICKA



VILIM FELLER

Vilim (William) Feller, a mathematician of world renown, was one of the great men of science born in Croatia. He was born in Zagreb on 7 July 1906 to Eugen Viktor Feller, pharmacist and successful businessman, who had a pharmacy and a factory of hygienic and cosmetic products based on his pharmaceutical specialty Elsa-fluid in Donja Stubica. The family later moved to Zagreb, where they lived in their villa in Jurjevska Street no. 31a. Vilim graduated from secondary school and completed the first two years of university studying mathematics in Zagreb (academic years 1923/24 and 1924/25). The enrollment documents at the Faculty of Philosophy give Stubica Donja as his home municipality. In 1925 Feller went to Goettingen, and obtained his doctorate in 1926 with the thesis uber algebraisch rektifizierbare transzendente Kurven. He was habilitated in 1928 and became assistant professor in Kiel, where he remained until 1933 when he left Germany because the Nazis came to power. He continued his career in Copenhagen, Stockholm and Lund. In 1939 he went to the United States of America and received American citizenship in 1944. He was professor at the distinguished American universities Brown and Cornell, and in 1950 he became professor of mathematics at Princeton, where he remained until the end of his life. He died on 14 January 1970 in the Memorial Hospital in New York.

Feller's scientific work (104 papers and 2 books) is very varied and is an important contribution to analysis, measure theory, geometry, functional analysis and differential equations. Until 1950 his most important work concerned classical limit theorems in probability, especially the central limit theorem (the Lindeberg-Feller condition). His work on the law of the iterated logarithm, to which he gave final form, is of great importance. Feller's programme on one-dimensional diffusions, which are the best studied class of stochastic processes, lasted from 1950 to 1962. Here Feller established deep links between analysis and probability. Markov processes, which satisfy certain analytical conditions, are generally known as Feller processes. Feller also initiated the general theory of boundaries for Markov processes, and gave a great contribution to the renewal theory and the theory of branching processes.

The present importance of the modern mathematical theory of probability is greatly due to W. Feller, who was one of its founders and leading mathematicians. His name will be lastingly remembered alongside those of J. Bernoulli, A. de Moivre, P. Laplace, D. Poisson, P. Bebišev, A. Markov, E. Borel, N. Wiener, P. L‚vy, A. Kolmogorov, A. Hincin, J. Doob and G. Hunt. Many concepts in the theory of probability bear Feller's name, for example: Feller processes, Feller transition functions, the Feller test for explosions, Feller semigroups, Feller Brownian motions, the Lindeberg-Feller theorem, the Feller property. While he was at Princeton, Feller published his well-known books on probability theory, which greatly influenced the spread of modern concepts in this field. They are considered among the best mathematical text-books written in the twentieth century. Feller was also the first executive editor of what is today the leading mathematical referential journal Mathematical Reviews, giving thus another contribution to the mathematical world.

Feller received many acknowledgements in his lifetime. We must especially mention membership in the National Academy in Washington, in the American Academy of Arts and Sciences in Boston, in the Danish Academy, honorary membership in the Royal Statistical Society in London, and membership in the Yugoslav Academy of Sciences and Arts. In 1970 he was awarded the highest American honour, the National Medal of Science for 1969, bestowed by the President of the United States of America. Sadly, he died a short time before the awarding ceremony, and the medal was received on 16 February 1970 in the White House by his widow Clara.

MILISLAV DEMEREC

FROM CROATIA TO THE UNITED STATES OF AMERICA

Born in Croatia, Milislav Demerec attended school and university in his homeland. Then, guided by his interest in genetic research, he first went to France, and finally to the United States of America, where his fruitful life was completely devoted to biology and genetics. H. Bentley Glass said that after his arrival in Cold Spring Harbor "the following four and a half decades, to the moment of his death, can be identified with the personal career of Milislav Demerec and his results, as one of the really few. He was one of the twelve geneticists whose work brought the United States to the fore in this field of biology".

In 1941, Demerec was offered the post of director of the Biological Laboratory in Cold Spring Harbor, and in 1943 the post of director of the Section for Genetics in the Carnegie Institute in Washington. For the rest of his life he kept both appointments and was devoted to both institutions until 1960. In this period solid foundations were laid for the present revolution in molecular biology and molecular genetics, making Demerec important in American science, in the history of world genetics, and in Cold Spring Harbor, with its "Golden Age" - known as "The Demerec Age".

What is a gene? - this was the question that Demerec devoted his life to answering, always seeking for better and more precise answers and constantly changing to experimental models that offered better systems to give more exact answers. Starting with genetics (Zea mais), he turned to the problem of the changeable, mutable genes of another plant, Delphinium ajacis.

The second period in Demerec's research began with the use of X-ray induced mutagenesis and research into damage in various species of Drosophila. With the introduction of the analysis of polytene chromosomes of salivary glands in the species Drosophila melanogaster, work on damage and other types of chromosome aberration progressed well. However, during the Second World War Demerec changed the priorities of his laboratory and concentrated on an acute problem: how to apply Sir Alexander Fleming's discovery of the antibiotic penicillin so that it could be used in clinical practice, on the battlefields of Europe, and in war hospitals. He and his associates began to research the effects of radiation on the mould produced by penicillin, Penicillium notatum, and they discovered a mutation that fantastically increased its production and enabled its pharmaceutical exploitation. This was the first great breakthrough in the "Antibiotic Era".

The excellent new antibiotic streptomycin was obviously a great hope, but the discovery of frequent mutations of the tuberculosis bacillus (Mycobacterium tuberculosis) making it streptomycin resistant encouraged Milislav Demerec and his group to insist on the principle of polychemotherapy to combat dangerous bacterial diseases. At that time the combination of streptomycin and PAS (para-aminosalicylic acid) proved a perfect combination for the treatment and successful prevention of the spread of tuberculosis. In 1952 Demerec placed himself at the head of what was practically an open battle for a good strategy of combining several antibiotics to prevent the appearance of resistant bacterial varieties, even against the Food and Drug Administration and its recommendations. Soon his theoretical views were confirmed and encouraged by clinical experimentation.

These practical medical challenges, and Demerec's constant search for the best organism with very high issue, that would enable the discovery of the fine structure and function of genes and their distribution, led him into the world of bacteria. Two alimentary bacteria, Escherichia coli and Salmonella typhimurium, occupied his attention in his most productive mature years.

Demerec was also very active outside Cold Spring Harbor, for example at Columbia University, Brookhaven National Laboratory, the Rockefeller Institute for Medical Research, and as a lecturer throughout the United States, Europe, Africa and South America. He carried out various offices in the American Genetic Association, from secretary to president, and he performed the same offices in the American Society of Natural Scientists.

Milislav Demerec became member of the National Academy of Sciences of the USA, and the American Philosophical Society. He was honorary member of the American Academy of Arts and Sciences, New York Academy of Sciences, and the American Association for the Advancement of Science. Dr Demerec was also President of the Section for Zoology and Anatomy of the National Academy of Sciences.

Thanks to his achievements and work, Demerec became honorary member of the Royal Danish Academy of Science and Letters, the British Genetical Society, Croatian Academy of Science, Genetical Society of Japan, Biological Society in Santiago and its Medical Faculty. He was awarded an Honorary Law Doctorate by the Hofstra College and became Doctor honoris causa of Zagreb University. Evelyn Witkin said of Milislav Demerec: "He served genetics well, and his life and work will be an indivisible part of the history of genetics for all times."

VLADIMIR PRELOG

(SARAJEVO 1906)

This exhibition gives us a splendid opportunity to congratulate Professor Vladimir Prelog on his 90th birthday. He is one of the greatest organic chemists of the twentieth century, the living history of chemistry, a man who still regularly comes to work on time every day.

Vladimir Prelog was born on 23 July 1906 in Sarajevo, where he attended elementary school. He started grammar school in Osijek, and matriculated in Zagreb. He graduated from the Technical College in Prague, where he obtained a doctorate in 1929. He spent six years in Prague as head of the laboratory for the production of fine chemicals, and then returned to Zagreb and began his academic career at the Technical Faculty. From 1935 to 1940 he was assistant professor, and from 1940 to 1941 associate professor of organic chemistry. In December 1941 he joined Professor RuÏicka's laboratory at the Eidgenossische Technische Hochshule (ETH) in Zurich, where he climbed very quickly up the hierarchical ladder and in 1957 succeeded RuÏicka as head of the Institute. He enlarged and modernized the Institute, and democratized it introducing collective management. In 1976 he retired, and since there is no status of emeritus professor at the ETH, he inscribes further semesters as a Fachh"rer (auditor) and is still active.

In 1933 he married Kamila Vitek and they have a son Jan (1949).

Prelog opted for chemistry and science when he was very young, and he published his first scientific paper as a grammar-school pupil in Osijek in 1921. This always remained his field and his work resulted in 24 patents and 417 publications. He loves his work and the following old Chinese proverb can readily be applied to him: "If you want to be happy one evening, buy a bottle of wine, one week, kill a pig, one year, get married, but if you want to be happy for the whole of your life, you must love your work."

Prelog's important scientific work was in the field of the organic chemistry of natural compounds, and the stereochemistry of organic compounds and reactions. In this framework, the search for symmetry and order in the world of chiral and asymmetric chemical compounds has permeated all his work.

He was scientifically profiled in Zagreb with a brilliant synthesis of quinuclidine and kindred bicyclic derivatives, the partial synthesys of antimalaric quinine, and especially the synthesis of adamantane, a marvelous natural substance of diamond structure. In Zurich, he and RuÏicka embarked on the isolation and determination of the structure of products of animal origin, mostly compounds of a steroid structure. But Prelog soon began to follow his own path. From products of an animal origin, mostly alkaloids, he turned to the synthesis of cyclical compounds of medium size rings. From that work stemmed the basic postulates of conformational analysis and the today well-known phenomenon of the secondary deuterium isotope effect. Then followed asymmetrical syntheses, enzymatic reactions, products of a microbe origin, mostly antibiotics, stereochemical studies, and conceptual, toloplogical and P in CIP /C(ahn)-I(ngold)-P(relogo)/ rules for the specification of molecular chirality, which won him the Nobel Prize in 1975.

After retiring he devoted himself to the study of structure recognition and complexation. Prelog's last experimental project was in this field, of great importance for understanding analogue biochemical processes. It culminated in the proposal of a model of stereoselective complexation of tartaric acid esters with aminoalcohols, shown with a diamond structure. This brought "Prelog's research wheel" to its beginning, to adamantane and its diamond structure.

At Zagreb University Prelog was the first to teach the science, skill and art of organic synthesis. Immediately after coming to Zagreb in 1935 he established close cooperation with the small chemical plant Kaštel, the forerunner of today's Pliva, for which he patented his discoveries. He showed at that early time how successful cooperation between university and industrial research laboratories can be, although this is a rather sensitive and complicated relationship. Although his work in Switzerland interrupted his work in Croatia, in the few years in Zagreb (48 research papers, 8 patents and 5 dissertations) he managed to establish Prelog's School of organic chemistry in Zagreb. He never cut his ties with the country from which he came, and he followed the development of his school even in Zurich. He keeps in constant touch with his former associates, and many young Croatian organic chemists are still doing their doctoral and post-doctoral studies in his laboratory at the Faculty of Electrical Engineering. Most of them return to Zagreb, revitalizing Prelog's School of organic chemistry in Zagreb so that it continues to live and pass down the teaching of its founder.