FEBRUARY 15, 1884.] 
Siemens machine, and the spring which it works, are 
arranged on a walnut cross-piece. In addition, it is 
held by stretched ropes, which may be tightened at 
pleasure by tension, and which connect the four 
extremities of the framework with the upper and 
lower cross-pieces of the car. 
When rotating with great 
velocity, the vibrations are 
avoided by this method of 
attachment. 
The use of such a machine 
in the car of a balloon is 
comparatively simple. When 
SCIENCE. 
199 
sixth the natural size, and showing clearly the char- 
acteristic features. It has two pairs of ante-orbital 
openings, the small front pair not having been seen 
before in dinosaurs. The brain inclines backward, 
and has a very large pituitary body, enclosed in a 
every thing has been pre- 
pared on the ground, there is 
nothing to do but to plunge 
a little copper fork into the 
mercury-cup of the commu- 
tator, and the screw begins 
to turn. 
From fear of fire, and from 
the change of position, which 
affects the altitude of the 
balloon when once poised in 
the air, the operator must 
have no manual work to do: electricity alone supplies 
all the fundamental conditions of the aerostatic mo- 
tor-force. After the winter, when favorable weather 
comes, the first electric balloon will again take its 
flight. GASTON TISSANDIER. 
A NEW AND STRANGE DINOSAUR. 
PROFESSOR MARSH continues his studies of the 
Jurassic dinosaurs of America by giving, in the last 
number of the American journal of science, an ac- 
count of a new fam- 
ily of Sauropoda 
founded upon the 
genus Diplodocus, 
which he places be- 
tween the Atlanto- 
sauridae and _ the 
Morosauridae. The 
chevrons of the 
caudal vertebrae, 
which have both an- 
terior and posterior 
branches, have sug- 
gested the name Di- 
plodocus; and the 
ischia of the pelvic 
girdle are interme- 
diate in form and po- 
sition between the 
families heretofore 
recognized, the shaft 
being straight, and 
not twisted nor api- 
cally expanded. 
But the best preserved portion is the skull, of 
which we reproduce Professor Marsh’s excellent fig- 
ures. It was of moderate size, the figures being one- 
¥ie. 2. — The same skull, front view. 
MM 
GY) 
Fie. 3. —Skull and brain cast of the same, seen from above. a, aperture in maxillary; 5, 
ante-orbital opening; c, nasal opening; c’, cerebral hemispheres; d, orbit; ¢, lower tem- 
poral fossa; 7, frontal bone; 7”, fontanelle; m, maxillary bone; m’, medulla; n, nasal 
opening; oc, occipital condyle; o/, olfactory lobes; op, optic lobe; p, parietal bone; p/, 
pre-frontal bone; pm, pre-maxillary bone; g, quadrate bone; gj, quadrato-jugal bone. 
capacious fossa below the main brain-case, —a very 
different condition from that holding in the other 
families of Sauropoda. The size of the skull indi- 
cates an animal probably forty or fifty feet long: the 
weak dentition shows that it was herbivorous, and 
its food was probably such succulent vegetation as 
an aquatic life would enable it to procure. 
In looking at these figures, and noting their strange 
resemblance to a horse’s skull, one finds it hard at 
first to recall the fact that the nearest living allies of 
Diplodocus are the crocodiles. 
THE FALSE PROPHET OF THE 
SUDAN. 
THE religious movement in the Sudan has a spe- 
cial interest for ethnologists on account of its paral- 
lelism with the events by which the faith of Islam 
was originally propagated. A recent letter from 
Khartum informs us that Mohamed Ahmed, the 
Mahdi, was born at Dongola in the year 1260 of the 
hegira. His parents, Abdellahi and Amina, were 
poor, and had two older sons. From the age of 
seven he was taught in a Mussulman school to read, 
write, and commit to memory the Koran. At the 
age of twelve he knew the latter perfectly. In 
the same year his father died; but his brothers con- 
tinued his education while he pursued studies of the 
Mussulman law, foreseeing eminence in store for 
him. After the death of his mother, having com- 
pleted his studies, he repaired to the Isle of Aba on 
the White Nile, to be near his brothers, who were 
boat-builders. For nearly fifteen years he inhabited 
the isle, venerated as a holy man by all who knew 
him, before making claim to the title of Mahdi or 
Mussulman Messiah. He then wrote to all sheiks 
and grand dervishes of the region, that the prophet 
