Revieivs — Dr. Tempest Anderson — Volcanic Studies. 161 



a similarly illustrated paper on the Volcanoes of the Two Sicilies. 

 He has also been in the habit of exhibiting at the soirees of the 

 Royal Society, and these exhibitions were systematized into four 

 lectures (the Tyndall lectures) delivered at the Eoyal Institution. 

 It is scarcely to be wondered at that, with such a- record, 

 Dr. Anderson was appointed a member of the commission sent 

 out last Summer by the Royal Society to investigate the results 

 of the eruptions in the Windward Islands. Oddly enough, he was 

 on the point of bringing out the present work when this journey 

 was commenced, so that the delay has enabled him to introduce 

 a few of his West Indian photographs. 



The first seventeen plates of the work, together with their 

 explanatory text, are devoted to Vesuvius and its vicinity, and in 

 this connection the eruption of 1898 occupies an important place. 

 The character of these lavas is strikingly exemplified, especially 

 where the picture is taken at close quarters, showing a coulee of 

 lava of the corded type (a slaggy lava). This stream is small and 

 narrow, whilst some of the loose blocks around approach the cindery 

 or scoriaceous type of lava. For comparison there is a photograph of 

 blast furnace slag from Seaton Carew. Here we perceive the effects 

 of a tip of molten slag down a spoil-bank, thus producing a flow of 

 artificial corded lava marvellously like the natural product. These 

 two types of structure, viz. the corded (slaggy) and the cindery 

 (scoriaceous), are mainly dependent on the amount of aqueous 

 vapour, which, if excessive, renders the cooling stone vesicular, so 

 that a lava-stream may be slaggy in one part and cindery in another. 



Next we are presented with the actual phenomena of eruption 

 as noticed in the middle of September, 1898. One of these pictures 

 shows the moving of lava on the steep slope in the act of solidifying 

 as a cascade of stones, in this case of the scoriaceous type. The 

 picture is so graphic that we might almost fancy we heard the 

 rattling. Then we are shown a part of the crater, as it existed 

 during a phase of the same eruption — a vast pit probably a quarter 

 of a mile in diameter, with almost vertical sides, the actual depth 

 being obscured by the vapours issuing therefrom : the quaquaversal 

 inclination of the strata of lava and tuff is well brought out. 

 Showers of red-hot stones were coming out of the bottom of the pit, 

 but the author was fortunate perhaps in not being able to photograph 

 any of these. Finally, we have in pi. x a picture of the explosion, 

 which occurred two days afterwards, as seen from the Observatory, 

 the magnificent cloud of vapour and ashes being intensified by the 

 slanting rays of the sun. 



These photographs of the phenomena of eruption more especially 

 appeal to the vulcanologist, but there are others likewise of great 

 geological interest. Ever since the days of Lyell the Phlegrsean 

 Fields have been classic ground for all those who seek to interpret 

 the past through the action of the present. There is probably no 

 more exquisite example of a crater, presumed to be extinct, than 

 that of Astroni (pi. xiii), whose picturesque and wooded interior 

 affords such a telling section of consolidated volcanic ash dipping 



DECADE IV. — VOL. X. — NO. IV. 11 



