THE MEDITERRANEAN 'NATURALIST 
288 ' 
A 'ateeMike "grass : frctoii the volcanic slopes of ] 
Oran;, Alger®, is 1 - said tube so elastic that it can be I 
used instead of Springs in the manufacture of fur- ; 
nitur'e. 
After , the pye&ent year, , the Centigrade thermo- 
meter is to take the place of the Reamur as the 
official standard throughout -Germany. 
At present 150 species of plants are cultivated 
in Egypt, but Dr, Schweinfurth finds that only 
about 50 were grown before the Christian era. 
A remarkable continuance of an inherited prac- 
ticed that of migratory birds which are said to 
cross the Mediterranean at a point proved to have 
been once the narrowest part of the sea, but which 
is far from being so now. 
A solution for checking , potato disease-consist- 
ing, for. an acre, of 22 lbs. suphateof copper, 22 lbs. 
unslaked, lime, and . , 100 gallons of water — was 
lately Tried .on an English experimental farm. 
The. unsound tubers from. a treated plot weighed 
11 lbs.- those from an untreated plot, of exactly 
the, .same, size and number of plants, 686 lbs. 
Certain curious leaf-insects of the tropics have 
wings ’ that mimic leaves not only in color but in 
the veips, and on the; ground so closely resemble 
leaves that even , ants are deceived. Dr. Sharp 
tells the' London Linhean Society,' moreover, that 
this .resemblance ^mounts almost to identity of 
minute 1 structure, and the coloring matter cannot 
be distinguished' froin that of leaves. Even the 
eggs have a’ strikingly vegetable appearance. 
The popular belief that the increase in the size 
of glaciers recurs every seven years has not been 
confirmed by the studies of Prof. Forel, who 
finds that while definite figures cannot be given- 
the cycle of glacial variation must be as much as 
35 to 50 years. 
The glaciers of the Alps seem to have been at 
maximum in 1850 or 1855, and they continued 
steadily to diminish until 1870, when not one was 
known to be on the increase. In 1875 a glacier of 
Mont Blanc began to lengthen, two others began 
to increase' in 1878 and 1879, and this was soon 
followed by an increase of some 30 glaciers of 
different valleys of Le Valaisl Many large glaciers, 
however, are still decreasing or stationary, and it 
is probable that the maximum stage c: g! iciers 
will not be reached until the beginning of next 
century. 
From many observations and experiments Mons. 
Ph. Lenard finds that drops of water falling upon 
water or wet bodies generate electricity, the water 
becoming electrified positively, and the air escaping 
negatively electrified from the foot o: the fall, and 
light impurities in the water diminish the effect 
considerably. The essential conditions of electri- 
fication are the concussions among the drops them- 
selves and against the wet rock, no effect being 
due to the waters fall through the air and its 
dispersion by it. A jet of water falling, from an 
insulated tank to an insulated pail electrified the 
latter positively, while the negative electrification 
of the surrounding air grew to several hundred 
volts. Sparks were obtained from waterfalls. 
The strength of England and of the English 
race in North America, says Prof. N.S. Shaler, the 
dominance in the world of that peculiar kind of 
man, depends upon coal : and this in an immediate 
way hinges upon the peculiar conditions of geogra- 
phic development which caused the plain-lands of 
North America alternately to sink iuto and rise 
from the sea in perhaps a hundred oscillations in 
in the course of one geological period. 
In its life forms Australia is known to be stran- 
gely different from other lands, and reasons have 
appeared for looking upon it as a .survival of the 
Secondary and Tertiary periods- -a region that has 
grown old less rapidly than the rest of the world. 
“We know,” observes a writer in Science Gossip, 
“that within the period called Tertiary, gum-trees 
banksias, Moreton Bay pines, and other now 
distinctly native Australian trees, grew in England. 
During the Secondary period the only warm- 
blooded mammals in Europe were marsupials, 
resembling those peculiar to Australia. Every 
now and then some new fossil mammal turns up, 
but it is almost certain to be of the Australian 
type. For instance, a large number of fossil mam- 
malian bones have just been discovered in the' 
Tertiary strata in Patagonia, and they have been 
proved to be nearly related to the pouched or 
marsupial 'wolf f Thytacin\ *) of Tasmania,” 
