424 
POPULAR SCIENCE REVIEW. 
from the bark of the buckthorn] (Rhamnus franguda) by treating it with 
dilute soda solution (“ Ber. deut. Chem. Gesell.,” ix. 1775). An analysis 
of the purified substance gave numbers corresponding with the formula 
C 15 H 10 O 5 , which Liebermann has shown to be that of emodin, first obtained 
by Be La Rue and Muller from rhubarb root. The bark of the buckthorn 
contains about 0*2 per cent, of this substance. When distilled with zinc 
powder it yields a mixture of anthracene and methyl-anthracene. Whether 
frangulinic acid also exists in tbis bark has not yet been determined. 
The Phosphorescence of Organic Compounds. — Radziszewski finds that 
formic aldehyde and grape sugar, when mixed with an alcoholic solution of 
potash, and warmed in presence of air, become phosphorescent (“Beiblatter 
Ann. Physik und Chemie,” 1877, i. 242). As Duchemin has noticed that 
Noctiluca milicris can produce a burning sensation on the skin, it appears 
possible that it may secrete formic aldehyde, which changes in presence of 
oxygen to formic acid. The phosphorescence noticed in the case of grape 
sugar is a further indication of the probability of its being of the nature of 
an aldehyde. Neurine, which does not form aldehyde under similar circum- 
stances, is not phosphorescent. 
Action of Carbonic Acid . — Mohr has called attention (“ Annalen der 
Chemie,” clxxxv. 286) to a number of apparently anomalous decompositions 
produced by carbonic acid, in which stronger acids, such as phosphoric acid, 
acetic acid, and chromic acid, are expelled from their compounds by means 
of carbonic acid. 
GEOLOGA AND PALAEONTOLOGY. 
A Gigantic American Dinosaur . — The Cretaceous deposits of Colorado have 
lately yielded portions of a Dinosaur, which would appear to have exceeded 
in magnitude any terrestrial animal of which we have any knowledge. 
Professor Marsh descibes it (“ Sillimaus Journal,” July, 1877,) under the 
name of Titanosaurus montanus. The most characteristic parts preserved are 
the last two sacral vertebrae, with their transverse processes, and portions of 
the posterior limbs. The vertebrae are remarkable as having such deep con- 
cavities as materially to lessen their bulk, in which they somewhat agree with 
those of Eucamerotus or Streptospondylus , described by Mr. Hulke ; but in 
some of the vertebrae, at any rate, there are cavities in each side, which 
communicate with the surface of the vertebrae through a foramen opening 
below the base of the neural arch. These cavities the author believes to be 
pneumatic. From the measurements of the parts preserved Professor Marsh 
estimates the length of the entire animal at from 50 to 60 feet, and he be- 
lieves it to have been herbivorous, and a distant ally of the small Hadro- 
saurus agilis, the only Dinosaur hitherto found in the Cretaceous of Kansas. 
A Carboniferous Hexactinellid Sponge. — Mr. Carter has called attention 
(“Ann. Mag. Nat. Hist.,” Sept. 1877) to the occurrence in the lower 
Carboniferous Limestone of Dairy, Ayrshire, of fossilized portions of a 
sarco-hexactinellid sponge, allied to Hyalonema. The fossils consist of 
spicules and fragments of spicules, among which are “the hexactinellid 
spicules of the body in situ , the long linear anchoring spicules, in at least 
