Eevieivs—Palmieri and Mallet on Vesuvius. 121 



bombs, properly so called, are drops or masses of liquid and incan- 

 descent lava, launched from the surface of the molten mass in the 

 crater by its gaseous explosions, and rounded by the resistance of the 

 air as they ascend and descend again, just in the same way that drops 

 of molten lead are rounded into shot by their fall from a 'shot-towei'.' 

 But this mode of formation would not account "for spherical masses 

 of such vast size as Professor Palmieri describes, enveloped in the 

 flowing lava. The origin of these masses, which can hardly be 

 true ' bombs,' deserves more careful investigation. Perhaps they are 

 only spherical concretions, such as are not unusual in cooled lavas. 



Another interesting point connected with this eruption was the 

 quantity of sea-salt (chloride of sodium) evolved in the vapours and 

 brought down with the rains, so that "not only the Vesuvian cone, 

 but the whole adjacent country, appeared white for many days, as if 

 covered with snow when exposed to sunlight." (p. 97). "The de- 

 struction of land in occupation of buildings and of crops exce'eded 

 three million francs in value." (p. 98.) 



The five woodcut-plates of Vesuvius, copies of photographs of the 

 cone, — four of them taken from the same point of the Observatory, — 

 before and after the eruption, are too obscure and rude to tell much 

 as to the change of form and height in the mountain, which are 

 matters of some importance, and ought to have been verified by care- 

 ful and frequent barometrical and trigonometrical observations. If 

 Prof. Palmieri, with his single assistant, and the two Priests, " en- 

 trusted with the festive mass for the Observatory," cannot carry out 

 this simple work, surely there are sufficient learned and scientific 

 bodies interested in it who would willingly contribute the needful 

 additional funds, to record such changes in the cone as must have 

 been occasioned by so notable an eruption as that of 1872, 



Mr. Eobert Mallet's Introduction has really no connection with 

 Palmieri's Eeport. It is partly occupied with a statement of his 

 views on earthquakes and volcanoes, or, as he is pleased to call it, 

 " Vulcanicity," and partly is made up of an exposition of his theory 

 of the djmamics of volcanic energy, as set forth in his paper com- 

 municated to the Eoyal Society last ye^v. 



What we chiefly object to in this portion of the volume, is the 

 assumption on Mr. Mallet's part of a conscious superiority to others, 

 and a freely-expressed contempt for all previous observers, especially 

 for geologists, "few "of whom "even appear to realize how great 

 and important are the relations of Vulcanicity to their science viewed 

 as a whole." (p. 78.) 



We fear Mr. Mallet, in making this remark, forgot at the moment 

 the fact that Mr, Poulett Scrope and Dr. Daubeny — but especially the 

 former — wrote on Volcanoes and their connection with physical 

 geology so ]ong ago as 1824-5, and Mr. Scrope has since frequently 

 written thereon; many of his papers having appeared in this 

 Magazine. 



Nor can the charge of neglecting this subject be brought against 

 Lyell or Phillips, whose published works attest their full apprecia- 

 tion of its importance. 



