HARD WICKE 'S S CIENCE G OSS IP. 



ihe resupinate habit, that is, the plants are fixed by 

 the cap to the matrix, and consequently the gills are 

 uppermost. Agaricus (Pleurotus) septicus is common 

 during the autumn on dead twigs and dung, white, 

 three to four lines across, pileus or cap downy, margin 

 incurved, gills rather distant with a yellowish tinge, 

 stem thin, downy, sometimes absent. A. applicatus, 

 similar in size and habit, is known by its ashy-grey 

 colour and entire absence of stem. A white sub- 

 gelatinous, more or less club-shaped fungus, three to 

 four lines high, and sometimes slightly branched and 

 •compressed, is not unfrequent on dead fern-stems ; this 

 is Pistillaria quisquilaris. Typhula, an allied genus, 

 is distinguished by the slender thread-like stem, which 

 is distinct from the club-shaped head, bearing the 

 hymenium or surface from which the spores originate. 

 The species are all minute, and grow from dead stems 

 or leaves ; most have a tubercle at the base of the 

 stem. T. filiformis is half an inch in length ; stem 

 very slender, decumbent, brown, without a tubercle, 

 club-shaped, white. T. crythropns, somewhat similar 

 in habit and appearance, is known by the tubercle at 

 the base of the dark, nearly straight stem. 



( To be contained.) 



A VISIT TO VESUVIUS DURING AN 

 ERUPTION. 



By Dr. Johnston Lavis, F.G.S., &c. 



AMONGST the many natural phenomena none 

 perhaps are of more interest to the geologist 

 than those of active volcanoes. These, although 

 numerous, taken as a whole, are widely distributed, 

 and many are situated in somewhat obscure and 

 uncivilized parts of the world. 



Of all the known active volcanoes, Etna and 

 Vesuvius are the most celebrated by historic records 

 of their various eruptions, especially the latter, 

 which has destroyed whole towns, rendered desolate 

 vast acres of cultivated land, and by which thousands 

 have lost their lives. One would imagine that 

 such examples as the destruction of Herculaneum 

 and Pompeii, and in later years of Torre del Greco, 

 •would warn people from building in such close 

 proximity. On the very lava stream that swept away 

 Torre is now built the new town, and many feet 

 above Herculaneum stands Resina, with its busy 

 ■streets, shops, churches, under the dark, scowling 

 brow of the huge fiery cone. Over lava streams not 

 fifty years old are pretty villas, and fertile gardens. 

 Who knows but that in a few hours all may be swept 

 away by vast rivers of liquid fire ? 



On November 3, 1879, the mountain began to 

 show slight signs of disquietude, which in the course 

 of a day or two developed into a minor eruption ; a 

 condition most suitable for study. From Naples 

 were seen to issue clouds of smoke and vapour, and 



at night could be seen the streak of reddish light 

 which denoted the crater full and the lava running 

 over the edge and pouring down the northern side. 

 This condition continued until the evening of the 

 thirteenth, when it was observable that masses of 

 pumice and lava were being blown some hundred 

 feet into the air, and looking at a distance like the 

 falling sparks of an exploded rocket. We determined 

 therefore to make our visit on the following day. 



We started from Naples with a bright, sunny but 

 cold morning, driving along the margin of that mag- 

 nificent bay, and over the bridge of the Maddalena. 

 Here stands the statue of St. Januarius, holding out 

 his hand in a forbidding manner towards the moun- 

 tain, over which he is accredited with some special 

 power. Then on through Portici to Resina, built 

 upon the mud produced by the ashes swept down by 

 the rain derived from the condensed vapour of the 

 great eruption, eighteen centuries ago last August. 

 At Resina we added to our party the celebrated 

 guide known as Andrea Maccaroni, who knows as 

 much of Vesuvian minerals as he does of his own 

 relations. We now, by the aid of three horses, com- 

 menced the first part of the ascent, that is up to the 

 observatory. The road winds over the lava streams 

 of 1767, 1839, 1858, i860. In the course of two 

 hours we arrived at our first stopping-place, having 

 alighted at various roadside sections to break open 

 some old rejected blocks. The observatory is well 

 presided over by Professor Palmieri, who, although 

 not present in person, was able to offer us his 

 hospitality by means of a Morse telegraphic instru- 

 ment in connection with the Professor's laboratory in 

 the University of Naples. 



The observatory is a solidly constructed building of 

 three stories in height ; it contains instruments espe- 

 cially for the study of Vesuvius. It is built upon 

 a ridge probably part of the edge of the ancient 

 Monte di Somma, the ancestor of the modern moun- 

 tain. Within the building is a small local museum, 

 laboratory, private apartments, and the rooms for the 

 various meteorological instruments, the most in- 

 teresting among the latter being the seismographs for 

 the graphical registration of both the vertical and 

 horizontal movements of the subjacent land. They 

 are so arranged that they ring an alarm bell and stop 

 a clock at the exact moment of the very faintest 

 earthquake. There are also the aerial electrometer, 

 pluviometer and pluviograph, anemograph, baro- 

 meters, and the various other necessary instruments, 

 together with some for experiments on hot lava. The 

 microphone has also been employed by Professor 

 Palmieri, but I believe, with little advantage, using 

 it to detect subterranean sounds. 



Having made this interesting examination of the 

 observatory and its contents, and also fortified the 

 inner man, we commenced our second but by far the 

 most difficult part of the journey, on foot. 



Imagine a cone some 1000 feet high, composed 



