[3] (P. 96). There are strong grounds for the gravest doubts that there exists any real connection of a physical character between Volcanic Eruptions, and Earthquakes more or less _approximately_ coincident only, in time of occurrence; the respective sites being widely apart, and the less the probability as the intervening distance is greater. The discussions of the large number of records that are to be found of such coincidences--mostly but partial, and in but _very_ few instances complete coincidences--by Perrey, von Hoff, and others, as well as by myself, do not tend to sustain the view that such imperfect contemporaneity is based upon any causative connection. The seismic region of Greece appears to have no _direct_ connection with that of Southern Italy: the band of connection, if any, seems to lie between Northern Italy, across the Northern Adriatic, by Ragusa, and thence spreading into Asia Minor.
[4] (P. 97). The abundance of coleoptera and of various other forms of insect life about lava beds, both recent and old, is a very singular fact, and one worthy of the careful observation of entomologists. In the autumn of 1864, at mid-day, when sitting sketching upon the lava about the middle of the Val del Bove (Etna), I found it almost impossible to work, or even to remain for an instant still, in consequence of the continual cloud of insects, large and small, that struck against me in flight, endangered the eyes, and swarmed upon my clothes. It is quite possible that this local superabundance of insect life may arise merely from the general dryness and warmth of such places, and the plentiful _nidus_ that the innumerable cavities in lava afford for the eggs and earlier stages of insect life; still, this apparition of one form of life may also be connected with other circumstances not unimportant to discover.
[5] (P. 120). The _Crocella_ is a small wooden cross, erected several years ago, and which one passes to the right hand at the upper end of the path along the ridge of tufa and volcanic conglomerate upon which the Observatory stands, in ascending thence to the Atria del Cavallo.
[6] (P. 134). That the causes assigned by Professor Palmieri for the potent developments of electricity (positive or negative) which characterise the ascent of the issuing columns of (chiefly if not always) _dry_ steam, with a relatively small volume of various gases, and throwing up, in their blast, volumes of small solid particles in ashes and lapilli, etc., and the subsequent fall as a mineral or stony hail-shower of the latter, through the partially condensing vapours and the circumambient air, are the main causes of electrical development evidencing itself in lightning flashes, is no doubt true. We must not, however, lose sight of the many other and very effective agencies at work here to produce electric excitement. The actual _bocca_ of the volcanic vent whence the steam roars off constitute the cone a veritable hydro-electric machine. Mechanical energy in various forms is transformed into electric energy. Chemical action is going on both in the solid and in the vapourous and gaseous emanations as they rush into and remain in the air or descend from it, and chemical action is transformed in part into electric energy. Percussion between ascending and descending particles and fragments, fractures and breaking up of more or less of these, thus and by sudden changes of temperature in cooling, are likewise operative. In addition, great and violent movements in the atmosphere itself result from the large local accessions of temperature by the heated volume driven up into it, and which in turn give rise to electric disturbance of the same character as those produced in wind storms and whirlwinds, brought about by the natural causes which every day effect disturbances in our atmosphere all over the globe.