54 
THE MEDITERRANEAN NATURALIST 
In the quarterly proceedings of the Manchester 
Geographical Society there is a most instructive 
article by Mr. Gustav Jacoby on '‘British trad. ■ 
with Algeria, Tunis, and the Sahara, the principal 
object of which is to direct the attention of Brit 
ish merchants to those markets in Northern Af- 
rica from which the French are, apparently, bent 
on ousting us, if we will allow them. 
The Archduke Ludwig Salvator of Austria 
has just issued a further instalment of his magni- 
ficent work on the Balearic Islands. The present 
volume contains an exhaustive descriptive account 
of Minorca. 
The Potato Disease.— Two forms of disease 
exist in potatoes. One is caused by a fungus 
known as Phytophora infestans. In this the lea- 
ves shew brown spots, which, if careful! exa- 
mined, exhibit a whitish border; this whitish 
down in the fungus in question. The leaf becomes 
flabby as the spot extends, and ultimately dies. 
The tuber itself remains hard, but shews brown 
spots and has a disagreeable taste when cooked. 
The other disease, in which the tuber softens, is 
caused by a bacterium known as Closteridium 
butyrieum , a species which is able to dissolve the 
cell walls, and to develop, butyric acid, by which, 
however, the starch contained in the tissue is not 
materially affected. After the potatoes are dug 
up this last disease may be arrested by putting 
the tubers in a dry, light, airy place. 
“La Neptunia ; ’ is the title of a new journal of 
natural history, that has lately been started at 
Venice. Among the many branches of natural 
science to which it is devoted, the following oc- 
cupy a prominent place. 
1. Physics of the sea, (bathymetrical, thermo- 
metrical <kc. 
2. Animals and plaits of the sea. 
3. Marine stations, laboratories, &c. 
4. The culture of fish, and Ocean expeditions. 
We strongly recommend this journal to all who 
take an interest in the natural and physical history 
of the Mediterranean and the adjoining seas. 
Subscribers should address Dr. D. Levi-Morenos. 
S, Samuele 3422,— Venice. 
An interesting discovery, consisting of a prehis- 
toric burial-ground, containing implements and 
other remains referable to the stone-age, has been 
made in Isnello, in the province of Palermo, 
Sicily. 
The general temperature of the Mediterranean 
from a depth of 50 fathoms down to the bottom is 
almost constantly 56' F. whatever may be the sur- 
face elevation of the bottom. This is a greater 
contrast to that of the Atlantic, which at a similar 
depth is at least 3° colder, and which at 1,000 
fathoms sinks to 40° Fall. 
Among the articles that will appear in our 
columns during the next six months are the fol- 
lowing: — The tarantula of the Mediterranean. The 
physiology of the Carobtree. Piecent foraminifera 
of the Mediterranean. The Natural history of 
Corsica. Plant resemblances. The Lepidoptera ( f 
the Maltese Islands. The Sirocco as an agent if 
denudation. 
The Eruption of Vesuvius 
of June 7th 1891. 
My suggestion that the second alternative type 
of eruptive activity would be that pursued by the 
volcano, which I published in several uewpapers, 
has been fully confirmed. Now for a period of 
over a month lava has continued to dribble forth, 
activity has returned to the central vent and no 
great changes have occurred. 
The throat of the volcano commenced to be 
cleared on June 9th, the vapour forcing its way 
up from the crater bottom at intervals through 
the choke of loose materials, and rose above as a 
column of dust; at the same time the powerful 
vapour blast issuing from the upper extremity of 
the lateral rift of which mention is made in my 
first letter. Each day I was kept informed of the 
state of the volcano by the kindness of Messrs 
Ferber and Treiber, the director and engineer res- 
pectively of the Vesuvian Railway. 
On June 15th I considered it right to again 
visit the mountain, and had the good fortune to 
be accompanied by Messrs Elliot, Lmden, Green, 
Newstead, and Treiber, several of whom are excel- 
