FIFTY CONCLUSIONS 
 
 RELATING TO THK ERI PTIX i: HIKX<>MENA OF 
 MONTE SOMMA, YEsrvirs 
 
 AND VOLCANIC ACTION IV GENERAL. 
 
 bv 
 
 H. J.'JOHMSTOX-LAVIS Esqr., M.D., M.R.C.S., B. is Sc., F. G. S., etc. 
 
 also a 
 
 L I S T 
 
 of 
 
 Books, memoirs, principal Ititterf ;;</, otlh'r signed publications of the author 
 
 1876 TO 189O 
 
 PRINTED BY KERRANTE, VICO TIRATOIO 
 M.1V. lS!)i) 
 
Itt. QETTY CENTER 
 LIBRARY 
 
FIFTY CONCLUSIONS 
 
 RELATING TO THE ERUPTIVE PHENOMENA OF MONTE SOMMA, 
 VESUVIUS AND VOLCANIC ACTION IN GENERAL. 
 
 by 
 H. J. JOHNSTOX-LAVJS Esqr. M. D., M. R. C. S., B. 6s Sc., F. G. S., etc. 
 
 PREFATORY NOTE 
 
 111 the years from 1879 to 1883 much attention was devoted by 
 me to the elucidation of the geological history and physical phenome- 
 na as illustrated Ivr the products of the great Neapolitan volcano. In 
 the spring of 1883 the results of my investigations were embodied 
 in a long memoir which was forwarded to the Geological Society of 
 London, where it was read on June 20 th 1883. ( Abstracts of the Pro- 
 ceedings of the Geol. Soc. London. Session 1882-83 ) p. 100 and in 
 part published in February 1884. Unfortunately much of Part I. re- 
 ferring to the origin of the mountain was excised as well as HO con- 
 clusions, at the end of my memoir, to which I had been led by my- 
 researches. This has exposed me to two inconveniences. In the first 
 place I have been violently attacked regarding my explanation of the 
 form of the Somma- Vesuvius massif which could hardly have oc- 
 curred, or at least that part which refers to the question of when 
 and how the Atrio crater was excavated , had the entire memoir 
 appeared. In the next place other writers at much later dates have 
 brougt forward deductions similar to my own. To prevent further 
 trouble I have now published the conclusions which I hope will serve 
 as a guide to vulcanologists in other regions. 
 
 Many of those conclusions have been extended and published 
 in another paper (The Relationship of the Structure of Rocks to the 
 Conditions of their Formation.) Scicntif. Proceed. R. Dublin Soc. 
 Vol.V., N.S., July 1880, pp. 113 to 150) which was first offered to 
 the Geol. Soc. of London, read, but refused publication (The Phy- 
 sycal Conditions Involved in the Injection, Extrusion and Cooling 
 
of Igneous Matter. ( Abstracts of the Proceedings of the Geol. Soc. 
 Lond. Session 1884-5. p. 78). As unfortunately many investigators 
 who occupy themselves with this question are unacquainted with 
 that paper, the conclusions that led up to its elaboration can now 
 be in their hands. 
 
 CONCLUSIONS AND DEDUCTIONS 
 
 1. Monte Somma is comparatively late as a volcanic focus in the 
 
 Campi Phlcgrsei , to which it belongs. 
 
 2. This is proved by the absence of leucitic rocks in the volcanic 
 
 tufa upon which it rests. 
 
 .?. There is no distinct evidence to prove that these latter igneous 
 products issued by the same vent that gave birth to Mt. Som- 
 ma. They were probably the result of submarine or sub-aerial 
 eruptions in the same volcanic area. 
 
 4. That the volcanic tufas earlier than Somma repose on late tertiary 
 
 marls etc. , of non volcanic origin, these again on the eocene 
 " Mac iff no" which in turn mantles the cretaceous appeuine 
 limestone. 
 
 5. Judging from what we know of the first appearance of all new 
 
 volcanoes, like them, this one commenced by an explosive 
 eruption. 
 
 6. That this first eruption gave rise to pumiceous ejectamenta similar 
 
 to products that were formed in its later intermittent stages. 
 
 7. This eruption has passed by gradation into a state of chronic 
 
 activity such as we see portrayed in the leucitic lavas in the 
 escarpment of the A trio. 
 
 8. This chronic activity was the great agent in building up the main 
 
 bulk of the mountain, and the phenomena were very similar 
 if not identical with those from A. I). 1031 to the present 
 day going on from the Yesuvian cone. 
 
 9. From arrest of supply of magma or exhaustion of heat in the 
 
 volcanic canal, the igneous forces failed for the time being to 
 make themselves shown at the surface, but were probably 
 storing up energy for a future outburst so producing an appa- 
 rent extinction of the volcano. 
 
 10. This apparent extinction was broken from time to time by 
 
 explosive eruptions. 
 
 11. These eruptions were due to the contact of superheated igneous 
 
 matter with water-bearing rocks , during which they ab- 
 
sorbed a certain amount of aqueous matter proportioned to 
 the temperature, pressure and length of contact. In this man- 
 ner the eruption would take place when the elastic tension 
 of the volatile constituent of the magma overcame the super- 
 incumbent pressure. 
 
 IS. This eruption might be hastened or determined by increased 
 pressure coming from below at the igneous reservoir or source 
 of igneous matter. 
 
 13. The products of such an eruption must have a tendency to be 
 
 fragmentary and vesicular in proportion to the temperature 
 and amount of igneous matter in the magma. 
 
 14. That vesicular structure is due to the molecular conversion of 
 
 the dissolved or combined aqueous matter into vapour. This 
 change resulting in the absorbtion of much heat, so as to 
 cause the rock mass to solidify before the vesicles could escape. 
 
 15. In rocks that have reached the surface, crystalline structure or 
 
 the proportion of formed matter that separates after ex- 
 trusion depends also upon the rapidity of cooling which is 
 seen to be chiefly due to the amount of included volatile matter. 
 
 16. That when this volatile matter is small in quantity, instead of 
 
 the igneous magma being torn assimder by its own inherent 
 expansion, il will issue as a continuous stream forming a lava 
 flow , which will possess a high temperature relatively to 
 what itroriginally had, less what would be lost by the expansion 
 and escape of aqueous vapour. 
 
 17. Cooling will be proportional to the last cause and to the rapi- 
 
 dity and viscisitudes of outflow. 
 
 18. That as extratelluric crystallisation of a pumice is in a ratio to 
 
 its rapidity of cooling, so also is that of lava. 
 
 19. This explains the fact observed at Vesuvius and elsewhere that 
 
 lava of fine grain contained much water and vice versa. 
 
 20. The most favourable circumstance to complete large consti- 
 
 tuent extratelluric-formed crystals are 1 st primitive high tem- 
 perature of the igneous matter, 2 nd the small loss of heat from 
 the paucity and therefore volatilization and escape of vapour, 
 3 rd the length of time the fluid magma is retained simmering 
 under low pressure in the chimney of a volcano. 
 
 21. That this also explains why the very small streams that gutter 
 
 over the edge of the vesuvian crater arc rich in large leucites 
 and pyroxenes as all those produced by the almost continuous 
 
outpour of lava during the last ten years, but are absent from 
 long streams such as the fine examples of 1872 and IftU. 
 
 ??. That there is a distinction between pumice and scoria. 
 
 ?:i. This difference depends upon the origin and character of their 
 respective vesicular structure. In the case of pumice, the ca- 
 vities result from the interstitial molecular separation and 
 union of a gaseous or volatile matter, which in part escapes 
 breaking up and carrying with it the fragments of the igneous 
 rock which from their consequent rapid cooling prevent the 
 escape of the residual vapour bubbles resulting in the spongy 
 structure. In scoria the vesicularity is due to the formation 
 of a froth, the cavities being formed not solely from the local 
 inherent volatile matter alone, but from that derived from 
 all the thickness of a mass of lava, which floats to the top to 
 form a scum. 
 
 As the vapour will only rise through the pasty mass when 
 the bubbles are of considerable size, the cavities in scoria 
 arc proportionally large in comparison to those in pumice. 
 
 As the mass-weight of a vesicular rock is dependent upon 
 the cubic area of the vesicles, other things being alike this 
 accounts for a pumice weighing less, bulk for bulk, than the 
 scoria. 
 
 The higher Sp. G. of the crystalline components of the scoria 
 also and the abundant vitreous matter composiifg the base of 
 the pumice will make a still greater difference between them. 
 
 24. That not only does igneous matter modify the rock walls in 
 
 which it is contained, but that they also may modify its com- 
 position bj* an interchange of chemical constituents. 
 
 25. That in an eruption the ejectameuta is made up of three ele- 
 
 ments. 
 
 Primary or essential. The true igneous matter in the form 
 of lava, pumice, scoria, ash etc. Secondary or accessory: 
 Materials derived from the crater walls of the cone i. e. 
 cooled rocks and othe*r products of earlier eruptions derived 
 from the same volcano. Tertiary or accidental: Rocks 
 which compose the basis of a volcano; and which may be 
 igneous, or sedimentary rocks derived from other sources. (1) 
 
 ( ) Perhaps the second of each of these terms is more suitable, so 
 avoiding any confusion of the yreat divisions of sedimentary rocks. 
 
26. A very high temperature and much aqueous matter produce* 
 a vitreous pumice. 
 
 : J 7. A very high temperature ami less aqueous matter produces a 
 microlitic pumice. 
 
 ?8. A high temperature and little aqueous matter produces a pu- 
 miceous scoria rich in large crystals, hut with a vitreous base 
 (within certain limits). 
 
 29. The two latter conditions hut especially the last seems most 
 i'avourable to the crystallization of Leucite. 
 
 :t(t. That it may be stated generally that Amphibole and Sanidine and 
 other felspars are commonest as minerals formed previous to 
 escape of explosive ejectamenta, (intratclluric) whereas Augite 
 and Leucite belong to the ejection ami subsequent period and 
 are commononest in non explosive lavas etc. 
 
 'II. That the pumice was not derived from the tearing up of earlier 
 trachytic rocks beneath M te Somina (Scrope) but were in each, 
 independaut productions from the heated matter producing 
 the eruption. If they were not so, we should expect each de- 
 posit to he a mixture of different kinds of pumice , whereas 
 by a single hand specimen the eruption can be determined by 
 which it was ejected. 
 
 .?. M 4 c Somma was originally a pretty regular cone, about 7000 
 feet or 2300 meters high. 
 
 .9.9. Each explosive eruption hollowed out or enlarged the size of 
 the crater up to a certain limit. 
 
 >4. Either the first or some later explosive eruption did not occur 
 from the original axis of the mountain, but from a point slight- 
 ly to the west of south of it. 
 
 :t.~>. The later of these eruptions enlarged the crater to such an 
 extent as to carry its apex below drainage level, thus modi- 
 fying the eruptive phenomena. 
 
 36. This crater extended below the base of the mountain through 
 the tertiary rocks into the Appenine limestone. 
 
 ::i . These rocks especially the latter were highly metamorphosed 
 by previous contact with igneous matter, thus accounting for 
 the great variety of ejected blocks. 
 
 9tf. That barancos produced by either one or two methods or both 
 combined, opened into the crateral hollow and drained it. 
 
 .9.9. The result of such drainage was the local deposit of a breccia 
 Phase III, period 4, on the slopes or foot of the mountain 
 
near that locality now seen in the Vallone <iraude and its 
 neighbour Valloue di Pollena. 
 
 In. That Lyell's statement that there were valleys of denudation 
 between one tafa and another is perfectly correct. 
 
 //. These valleys do not necessarily correspond to the recent ones, 
 but that probably little alteration has occurred in the basin 
 drained by each. 
 
 -12. The eruption that commenced as a violent explosive one pro- 
 ducing a very vitreous pumice by a series of probably inter- 
 mittent stages, terminated by the outflow of true lavas. 
 
 43. The products of the first outburst of an explosive eruption arc 
 
 much more vitreous and poorer in formed matter than that 
 ejected later , in which the expansive force has deminished. 
 This is the result of the longer time allowed for cooling by 
 that portion which is deepest in the volcanic chimney and 
 which also from being enclosed in dryer rocks had probably 
 absorbed less water. 
 
 44. The present chronic activity was the. gradual result of a series 
 
 of eruptions begining as an explosive one similar to that of 
 the year A. D. 79. 
 
 4o. The vesuvian cone is not concentric with the old M te Somina, 
 but it is roughly with that of the axis of the eruptions that 
 formed the great crater of the Atrio del Cavallo. 
 
 46. The valleys present different and special characters in different 
 
 parts of their course which depend upon the change in the 
 angle of inclination, and upon the kind of rocks traversed. 
 
 47. That the phenomena of the prehistoric volcano were- similar in 
 
 all respects to what we know as occuriug in historic times. 
 
 48. Volcanic action depends first upon variations of tension in the 
 
 primary igneous mass, and this is modified in violence and 
 the character of its products, by the different conditions to 
 which the escaping portion is subjected in reaching the sur- 
 face and its deposition there. 
 
 49. In all probability the volcanic products of the neigbourhood are 
 
 all derived from the same reservoir as that of Vesuvius, but 
 difference in composition and structure is due to the various 
 influences brought to bear on the original primitive matter in 
 its journey from its source, to its deposition upon the surface. 
 ~)(). That nearly all the superficial manifestations of volcanic action 
 can be explained without exception by this theory originating in 
 the study of, and illustrated by, Monte Somma and Vesuvius. 
 
LIST OF BOOKS, MEMOIRS, PRINCIPAL LETTERS AND OTHER 
 PUBLICATIONS OF THE AUTHOR FROM 1876 TO 1890 
 
 / 1870. On the Triassie Strata which arc Exposed in the Clifi- 
 sections near Sidmouth, and a Note on the Occurrence 
 of an Ossiferous Zone containing Bones of a Labyrintho- 
 don. Quart. Journ. Geol. Soc. Loud. Vol. XXXII, pp. 
 274 to 277, with 2 woodcuts & i plate. 
 
 2 1877. Notes on the Geology of Lewisham: Proceed. Geof. 
 
 Assoc. Lond. Vol. IV, pp. 528 to 543, with 5 woodcuts. 
 
 3 1878. A Glass-eating Lichen. " Science Gossip" N. 162. 
 
 June, pp. 128-130, with 4 woodcuts. 
 
 I 1879. A short History of the Town of Stalbridge, Staplebridge, 
 Stawbridge , or Stapleford , Dorsetshire. Stalltridye 
 Alnmnach (Header's ) for 1879, pp, 1 to 3. 
 
 -5 1880. A Visit to Vesuvius During an Eruption. "Science 
 Gossip." N. 181, January, pp. 9 to 10. 
 
 f> 1880. Volcanic Cones , their Structure and Mode of Forma- 
 tion. "Science Gossip." N. 190, Oct., pp. 220 to 223, 
 with 1 woodcut. 
 
 7 1881. On the Origin and Structure of Volcanic Cones. 
 
 "Science Gossip" N. 193, Jan. pp. 12 to 14 , with 4 
 woodcuts. 
 
 8 1880. Iron and Hydrogen. : "Nature," Vol XX H. p. 22O. 
 
 9 1880. Hardening of Steel. Ibid., p. 511. 
 
 10 1880. Note on the Comparative Specific Gravities of Molten 
 
 and Selidifed Vesuvian Lavas. Quart. Journ. Geol. Soc. 
 Lond. Vol. XXXVIII, p. 240 to 241. 
 
 11 1881. The Earthquake in Ischia. " Nature," Vol. XX HI, 
 
 p, 497. 
 
 12 1882. Diary of Vesuvius from Jan. 1 s * to July 10 th 1882. - 
 
 "Nature" XX IV, pp. 455 to 456 with 2 woodcuts. 
 
 13 1883. Earthquake in Naples. "Nature" Vol. XXVI, p. 151. 
 
 14 1883. Notice of the Earthquake of Ischia of March 4 th 1881. 
 
 Reports Brit. Assoc. Advancement of Science 1883. 
 
 15 1883. Notice of the Earthquake of Ischia of July 28 th 1883. 
 
 Ibid. 
 
 16 1883. The Disaster in Ischia. -- "Nature." Vol. XXV 111, 
 
 pp. 346 to 347. 
 
 17 1883. Observations scientiiiques sur le tremblement de terre 
 
_ 8 
 
 dii 28 Juillet 1888 a 1' isle d'Isohia. "IS Itnlif" \l}tn,n>\ 
 
 August 13 1883. 
 18 1883. II parere d' uno scienziato. 77 Piccolo" f.\(tirfcx/ 
 
 Sept. 2^ 1883. 
 l<) 1883. Previsions tic futures catastrophes dans Tile d'lschia. 
 
 " U Italie" (Rome) Sept, 2 nd 1883. 
 2() 1883. The Disaster in Ischia. " Indianapolis Journal." 
 
 Sept. 6* 1883. 
 
 21 1883. Una risposta al Prof. Pahnieri. "77 Piccolo" (Nfip/cs\ 
 
 Sept. 8th 1883. 
 
 22 1883. Kturte sur 1' emplacement des nouvelles villes a 1'ilc 
 
 d'lschia. " U Italic" (Rome) Sept. 15* 1883. 
 
 23 1883. Le costruzioni a Oasamieciola. "// Piccolo" (Najifcs, 
 
 Sept. SO" 1 1883. 
 21 1883. Rapport preliininaire sur le tremblenient de terre dit 
 
 28 Juillot 1883 a 1' ilo d'lschia. " L' Tfftfir."' Sept. 22 lul 
 
 1883. 
 25 1883. The Ischian Earthquake of July 28th 188:*. -- " Nn- 
 
 fure," Vol. A' A' nil, pp. 437 to 439, with a map. 
 *0 1883. Notices on the Earthquakes of Ischia of 1881 and 1883. 
 
 with a Map of the Isoseismals. In 8., pp. 56. with 1 map. 
 
 Naples 1883. 
 21 1884. The Remarkable Sunsets. "AW>v," Vol. XXIX. 
 
 p. 152. 
 
 28 1884. The Late Eruption of Vesuvius. Ibid., p. 29 L 
 
 29 1884. The Geology of Monte Soinma and Vesuvius, being a 
 
 Study in Vnlcauology. Quart. Jonrn. Oeol. Soc. Loml.. 
 Vol. XL, pp. 35 to 112. tritli 2 icoodcnts anrt I n'0i<>- 
 litliograpliic plate. 
 
 30 1884. Volcanoes on the Shore of Lake Nyassa, Africa. - 
 
 "Nature," Vol. XXX, pp. 62 to 63. 
 
 31 1881. Earthquakes and Seismographs. " Na'irrc" Vol. XXX . 
 
 pp. 608 to 612 with 5 icoodcuts. 
 
 32 1884. Brevi considerazioni intorno alia relazione del profes- 
 
 sorc L. Pahnieri sul tcrremoto dell' Isola d'lschia. " // 
 Piccolo" (Naples) Man-It 31 st and April pt 1884. 
 
 33 1885. Meteorite o Ciottolo? " It Piccolo" and "II Pm>- 
 
 f/olo" (Naples) Dec. 8i and 9 th ., "Roma," " Corr ;<>,-<> 
 del Mattino" (Naples) and " L' Italie" (Rome) Dec. W*, 
 "Piccolo, " "Pmu/olo" (Naples) Dec. 9 th and 10 th .. 
 (Naples) mid " L'KfW (Rome) of Dec. 10''. 
 
" L' If 'alie " (Rome) Dec. 12*, " The Times" (London) 
 Dec. ? 
 
 34 1885. The Physical Conditions Involved in the Injection, 
 
 Extrusion and Cooling of Igneous Matter Quart. Journ. 
 Geol. Soc. Loud. Vol. XL I, pp. 103 (o 106. 
 
 35 1885. Monograph of the Earthquakes of Ischia , a Memoir 
 
 Dealing with the Seismic Disturbances in that Island from 
 Remotest Times with Special Observations on those of 
 1881 and 1883 Lui.au, London ami Furchheim, Naples, 
 1885 in royal 4, pp. X and 112, with 20 photo-engrav- 
 ings, 2 large maps in color, 3 lithographic plates and 
 / chromo-litliographic plate. 
 
 36 1885. The New Outburst of LaA~a from Vesuvius. "Nature", 
 
 Vol. XXII, pp. 55 and 108. 
 
 37 1885. First Report of the Committee for the Investigation 
 
 of the Volcanic Phenomena of Vesuvius and its Neigh- 
 bourhood, Jlrff. Assoe. Reports, pp. 2, 
 
 38 1885. On the Preparation of Sections of Pumice-stone and 
 
 other Vesicular Rocks. Journ. R. Microscop. Soc., Set. 
 II. TV. 17 puff. 32-31. 
 
 39 1880. Sounding a Crater, Fusion Points, Pyrometers, and 
 
 Seismometers "Nature" Vol. XXXV, p. 197. 
 
 lo 1880. The Relationship of the Structure of Igneous Rocks 
 to the Conditions of their formation Sclent if. Proceed. 
 R. Lublin Soc. Vol.V, 'N.S., pp. 112-156. 
 
 H 1880. On the Fragmentary Ejectamenta of Volcanoes Pro- 
 ceed. Geol. Assoc. Vol. IX, pp. 421 to 432 with 3 fig, 
 
 12 1880. Krakatao, "Nature" Vol. XXXIII, p. 6. 
 
 13 1880. Vcsuvian Eruption of February 4 th 1880 , Ibid. 
 
 p. 367. 
 
 14 1880. Notes on Vesuvius from February 4 th to August 7 th 
 
 1880. Md. p. 557. 
 
 15 1880. The Eruption in New Zealand. Geol. Mag., Vol. HI, 
 
 Dsc. Ill, pp. 523-521. 
 
 If) 1880. The Relationship of the Activity of Vesuvius to Cer- 
 tain Meteorological and Astronomical Phenomena. Pro- 
 ceed. Royal. Soc. Lond. N. 243. p. 1. 
 
 17 1880. Second Report of the Committee for the Investigation 
 of the Volcanic Phenomena of Vesuvius and its Neigh- 
 bourhood. Brit. Assoc. Reports, pp. 3, also "Nature'' 
 Vol. XXXIV, p. 481. 
 
10 
 
 
 
 48 1887. L'Eruzioue del Vcsuvio ncl 2 Maggio 1885. Ann. 
 ft. Accad. 0. Costa d. Aspirant i Naturalisti. Era 3. Vol. 
 
 1, Naples, pp. 8 with 1 photo-engraving and i cromo- 
 lithograph. 
 
 19 IS87. Diario del t'ciioiiicui avvenuti al Vcsuvio da Luglio 1882 
 ad Agosto 1880. "Lo Spettatorc del Vesuvio e del C(imi>i 
 Flegrei." 1 Nuova serie pubbltcata a cura ea spese delict 
 Sezione Napoletana del Club Afpinv Ifaliano. Fiirchheiin 
 Napoli 1887 in 4., pp. 81 to 103 with 13 photo-en- 
 gravings. 
 
 30 1887. ( With Dr. G. C. V. Vosmacr ) On Cutting Sections 
 of Sponges and other Similar Structures with Soft and 
 Hard Tissues. Journ. R. Microscop. Soc. 1887, Part 
 
 2, pp. 200-205 with 1 woodcut. 
 
 51 1887. The Islands of Vulcano and Sfcromboli. "Nature" Vol. 
 
 XXXVI, pp. 13-14. 
 
 52 1887. Third Report of the Committee Appointed for the In- 
 
 vestigation of the Volcanic Phenomena of Vesuvius and 
 its Neighbourhood. Brit. Assoc. Reports 1887, pp. 3. 
 
 53 1888. On the Form of Vesuvius and Monte Somma. Geol. 
 
 Mag., Dec. Ill, Vol. V, pp. 443-451 with 1 woodcut. 
 
 54 1888. The Conservation of Heat in Volcanic Chimneys. 
 
 Brit. Assoc. Reports 1888, pp. '2. 
 
 55 1888. The Occurrence of Leucite at Etna Ibid. 
 
 56 1888. Not^ on a Mass Containing Metallic Iron Found on 
 
 Vesuvius IMd. pp. 2. 
 
 57 1888 Note on the Occurrence of Celestite Containing nearly 
 
 Fourteen per cent of Free Sulphur. Min. Mag. 1888, 
 
 58 1888. ( With Dr. T. Anderson ) Notes on the Recent Vol- 
 
 canic Irruption in the Island of Vulcano. Ibid, pp. 3. 
 
 59 1888. Fourth Report of the Committee for the Investigation 
 
 of the Volcanic Phenomena of Vesuvius and its Neigh- 
 bourhood. Ibid, pp, 7. 
 
 fj(J 1888. The Ejected Blocks of Monte Somma. Part I. Stratified 
 Limestones. Quart. Journ. Geol. Soc., Vol. XL IV 
 pp. 94-97. 
 
 fjl 1889. Further Notes on the Late Eruption of Vulcano Is- 
 land. "Nature," Vol. XXXIX, pp. 1O9-H1. 
 
 62 1889. The Recent Eruption at Vulcano. Ibid. p. 173. 
 
 63 1889. The Recent Activity of Vesuvius. Ibid. p. 184. 
 
 64 1889. The State of Vesuvius. Ibid, pp. 302-303. 
 
11 
 
 f>5 1889. The Present State of Seismology in Italy. Ibid, 
 pp. 329-331. 
 
 66 1889. Su una roccia contenciite leucitc trovata siill'Etna. 
 
 Boll. d. Soc. d. Microscopisti It., Vol. I. Fasc. 1-2, pp. 
 26, with one photo-engraving. 
 
 67 1889. On a Remarkable Sodalite Trachyte Lately Discovered 
 
 in Naples, Italy. Geol. Mag., Dec. III., Vol. VI., N.2, 
 pp. 74-77. 
 
 68 1889. L' Etat Actuel du Vcsuve. Bull. Soc. Beige de Geo- 
 
 logic, Hydrologie ef Paleontol., Vol. Ill, pp. 1-11 with 3 
 woodcuts. 
 
 69 1889. II Pozzo Artesiano di Ponticelli. Rend. d. R. Ac- 
 
 cad, d. Sc. Fis. e Mat. d. Napoli., Giugno 1889, pp. 7. 
 
 70 1889. Volcans et tremblements dc terre. A review of what 
 
 lias been published on these subjets during the year 1888. 
 U Annuaire Geologique Universe!. Paris 1889, Vol. V. 
 pp. 629-655. 
 
 71 1889. The New Eruption of Vesuvius. "Nature" Vol. XL. 
 
 p. 31. 
 
 72 1889. The Ponza Islands. -- Geol. Mag., Dec. Ill, Vol. VI, 
 
 pp. 529-535 with 3 woodcuts. 
 
 73 1889. Viaggio scientifico alle regioni vulcaniche italianc nella 
 
 ricorrenza pel centinario del Yiaggio alle due Sicilic 
 di Lazzaro Spallanzani. ( This is the programme of the 
 excursion of the cnglish geologists that visited the south 
 Italian volcanoes under the direction of the author. It is 
 here included as it contains various new and unpublished 
 observations ). Naples 1889 in 8., pp. 1-10 
 
 74 1889. Fifth Report Appointed for the Investigation of the Vol- 
 
 canic Phenomena of Vesuvius and its Neighbourhood. 
 Brit. Ass. Reports, 1889, pp. 12. with 5 woodcuts. 
 
 75 1890. The State of the Active Sicilian Volcanoes in Septem- 
 
 ber 1889. Scottish Geograph. Mag., Vol. VI, N.3, March 
 1890, pp. 145-150. 
 
 76 1890. Osservazioni geologichc lungo il tracciato del Grande 
 
 Emissario Fognonc di Napoli dalla Pictra sino a Pozzuo- 
 li. Rclazione alia Soclcta Napoletana degli Ingegneri 
 Costruttori di Napoli. Boll. R. Com. Geol., Vol. XXI, 
 N. 1 e 2., pp. 18-27 with 1 woodcut. 
 
 77 1890. Osservazioni geologichc sullc isole Veiitotcnc c Santo 
 
 Stefano ( Gruppo delle Isole Ponza ). Ibid. pp. 60-64. 
 
jo 
 
 78 1800. Nuovc osservazioni geologiche in Napoli e suoi diu- 
 torni ibid. pp. 65-68. (A curious error has been made 
 by the translator \vho seems to have been affected by a 
 mental Daltonism. ( On page 67, Hue 3, 6 and 9 for 
 "verdi" "read rossi" i.e. for " green " read " red. ") 
 
 ;<> J800. The Eruption of Vulcano Island. -- "Nature" Vol. 
 XLH, pp. 78-79. 
 
 .sv> 1HOO. The Extension of the Mellard Reade and C. Davison 
 Theory of Secular Straining of the Earth to the Expla- 
 nation of the Deep Phenomena of Volcanic Action. - 
 Oeol. Mag., Dec. Ill, I'ol. VII. June, pp. 246-249.