Obituary — Henry James Johnston- Lavis. 575 



After obtaining his M.ll.C.S.Eng. and L.S.A. in 1878 he married 

 Mile. Antonia Francjoise Bourdariat de Saint-Aupre, whose acquaint- 

 ance he had formed when at Marseilles, and who, he testifies in the 

 dedication to his last published work, "through a long married life 

 encouraged me in my medical and scientific work, affording me 

 valuable help and appreciation and aiding me to overcome almost 

 insurmountable difficulties." 



Having spent some time in 1879 as an assistant to a doctor in 

 Plaistow, and after taking the degree of B.esSci. Paris, he went out 

 at the end of the year to Naples. There he practised among the 

 members of the English and American colonies and the visitors, and 

 became Sanitary Director to Sir W. Armstrong's works at Puzzuoli. 

 In ] 884 he took the degree of M.D. Naples. His attention when 

 there was early directed to the part played by Edible Mollusca in the 

 dissemination of infectious diseases, a subject to which he recurred 

 later. Above all it was at Naples that he was started on his vulcano- 

 logical studies. To the young, energetic, and ardent geologist 

 Vesuvius, with its many fascinating problems, was a powerful load- 

 stone, and consequently all his spare time was devoted to its study 

 and survey. 



His first important memoir on the subject was laid before the 

 Geological Society in 1884. The paper was a long one and the 

 author not then an acknowledged authority on the subject, so some 

 condensation was insisted on before publication. Unfortunately, in 

 his absence from England this was not too wisely or sympathetically 

 done, and the omission of some portions spoilt the continuity of the 

 work, a fact Avhich involved the author subsequently in much useless 

 discussion. The views embodied in the memoir have, however, been 

 widely accepted on the Continent by competent authorities. 



Numerous other papers on subjects connected with Vesuvius and 

 the southern Italian volcanoes flowed from his pen during the 

 succeeding years, including a study of, and monograph on, the great 

 earthquake at Ischia, but his chief and perhaps most important work 

 was the completion under great difficulties of his survey of Vesuvius 

 during 1880-8, and publication in 1891 of the Geological Map in 

 six sheets on the scale of 1 : 10,000. Save for the addition of some 

 lava streams during the eruption of 1906 there is but little to alter 

 in the map to-day. 



He became a member of the Societa Geologica Italiana in 1889, 

 and during the autumn of that year the Geologists' Association paid 

 a visit to the southern Italian volcanoes, mainly at the instigation of 

 Dr. Lavis, on whom fell the brunt of the conduct of the party. 



In 1890 Lavis visited Iceland in company with Dr. Tempest 

 Anderson, and his observations there were published in a paper read 

 before the Scottish (now Eoyal Scottish) Geographical Society in 

 1895. Mention may here be also made to the joint paper with 

 Dr. J. W. Gregory on " Eozoonal Structure of the Ejected Blocks of 

 Monte Somma", printed in 1894, in which the authors gave the coup 

 de grace to ' Eozoon '. He was appointed Professor (Pareg.) of 

 Vulcanology in the Royal University of Naples in 1893, but never 

 delivered any lectures. 



